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Optically transparent polyimide (PI) films with good atomic oxygen (AO) resistance have been paid extensive attention as thermal controls, optical substrates for solar cells or other components for low Earth orbit (LEO) space applications. However, for common PI films, it is usually quite difficult to achieve both high optical transparency and AO resistance and maintain the intrinsic thermal stability of the PI films at the same time. In the current work, we aimed to achieve the target by using the copolymerization methodology using the fluorinated dianhydride 9,9-bis(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride (6FCDA), the fluorinated diamine 2,2-bis [4-(4-aminophenoxy)phenyl]hexafluoropropane (BDAF) and the polyhedral oligomeric silsesquioxane (POSS)-containing diamine N-[(heptaisobutyl-POSS)propyl]-3,5-diaminobenzamide (DABA-POSS) as the starting materials. The fluoro-containing monomers were used to endow the PI films with good optical and thermal properties, while the silicon-containing monomer was used to improve the AO resistance of the afforded PI films. Thus, the 6FCDA-based PI copolymers, including 6FCPI-1, 6FCPI-2 and 6FCPI-3, were prepared using a two-step chemical imidization procedure, respectively. For comparison, the analogous PIs, including 6FPI-1, 6FPI-2 and 6FPI-3, were correspondingly developed according to the same procedure except that 6FCDA was replaced by 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). Two referenced PI homopolymers were prepared from BDAF and 6FDA (PI-ref1) and 6FCDA (PI-ref2), respectively. The experimental results indicated that a good balance among thermal stability, optical transparency, and AO resistance was achieved by the 6FCDA-PI films. For example, the 6FCDA-PI films exhibited good thermal stability with glass transition temperatures (Tg) up to 297.3 °C, good optical transparency with an optical transmittance at a wavelength of 450 nm (T450) higher than 62% and good AO resistance with the erosion yield (Ey) as low as 1.7 × 10−25 cm3/atom at an AO irradiation fluence of 5.0 × 1020 atoms/cm2. The developed 6FCDA-PI films might find various applications in aerospace as solar sails, thermal control blankets, optical components and other functional materials. [ABSTRACT FROM AUTHOR]

This study prepares a series of hollow‐structured CS/SA/POSS composite gel spheres with a diameter of ~2.5 mm by using hydrophilic Janus‐type polyhedral oligomeric silsesquioxane (AS‐POSS) as a crosslinking agent in combination with sodium alginate and chitosan via electrostatic adsorption/free radical polymerization. As the content of POSS increases, the wall thickness of the gel spheres also increases from 20 to 30 μm, leading to a more compact and smooth wall structure in the polymerized CS/SA/POSS composite gel spheres. Additionally, the introduction and polymerization of POSS significantly enhance the stability, drug loading rate, and entrapment rate of the gel spheres, providing them with improved drug release capabilities. For hydrophilic drug doxorubicin, the loading rate and encapsulation rate reach 41.2% and 79.9%, respectively, while for the hydrophobic drug ibuprofen, they are 14.7% and 76.3%. Compared to some previously reported drug‐loaded gel materials, the gels prepared in this study demonstrate relatively higher drug loading performance. Thus, these hollow‐structured CS/SA/POSS composite gel spheres hold promise as innovative drug carriers in the biomedical field. [ABSTRACT FROM AUTHOR]

The importance of biopolymer-based nanocomposites in food packaging is growing significantly. Therefore, in the present study, we aim to examine the impact of zinc oxide (ZnO), polyhedral oligomeric silsesquioxanes (POSS), and, for the first time, their hybrid on polycaprolactone (PCL) nanocomposites. For this matter, different concentrations of 1, 3, and 5 wt% of each nanoparticle and the hybrid were incorporated into the PCL nanocomposites via the solution casting method. Their chemical structures and interactions, crystalline structures, and morphology were investigated by FT-IR, WAXD, and SEM. Moreover, it was observed through contact angle and surface free energy experiments that an increase in the nanoparticle concentration corresponded to an increase in the contact angle values. The incorporation of hybrid POSS and ZnO equilibrated well between Young’s modulus, tensile strength, and elongation of the samples in their single status. Accordingly, the addition of the hybrid nanoparticles up to 3 wt% significantly increased the modulus and yield strength of PCL nanocomposites without any significant sacrifice in toughness. Also, PPZ3 (containing an optimal 3%wt. of hybrid nanoparticles) demonstrated the lowest permeability against both water vapor and O2 gas, exhibiting reductions of approximately 30 and 55% when compared to pristine PCL. Finally, the antibacterial properties of the nanocomposite films were investigated for S. aureus and E. coli bacteria and revealed. In addition to the antibacterial properties of ZnO and POSS nanoparticles, increasing the concentration of hybrid nanoparticles up to 5 wt% expanded S. aureus’s inhibitory zone. The balanced mechanical, and barrier characteristics, enhanced morphologies, and antibacterial effects of the novel hybrid nanocomposites present novel opportunities in the field of food packaging. [ABSTRACT FROM AUTHOR]

Efforts to develop and implement an increasing number of biodegradable polymers continue to grow worldwide; nevertheless, substantial obstacles must undoubtedly be surmounted in order to produce biodegradable polymers that exhibit exceptional properties and high performance. With the objective of enhancing the compatibility between the two intrinsically immiscible polymers, polybutylene adipate-co-terephthalate (PBAT) and poly(butylene adipate) (PLA), we employed epoxidized polyhedral oligomeric silsesquioxanes (epoxy-POSS) nanoparticles. A solution-casting method was employed to fabricate nanocomposites comprising a nanoparticle and two biocompatible polymers. This process proved to be highly effective. The distinctive morphology, high strength, toughness, and thermal stability of these nanocomposites were demonstrated by a variety of experiments at 1 wt% nanoparticle. The opposite effect was observed when nanoparticles were added exceeding 1 wt%; consequently, the degree of compatibility between the polymer phases diminished. The impact strength and elongation-at-break of the composite samples were significantly altered at 1% nanoparticle application, going from 57.04 MPa and 520% to about 400% and 62.4 MPa, respectively, as compared to pristine PLA. Microscopic observations showed that the dispersion of nanoparticles in all three phases was dispersed, continuous, and the interface was uniform, and the presence of nanoparticles prevented the melt crystallization of PLA. [ABSTRACT FROM AUTHOR]

Optically transparent polyimide (PI) films with good atomic oxygen (AO) resistance have been paid extensive attention as thermal controls, optical substrates for solar cells or other components for low Earth orbit (LEO) space applications. However, for common PI films, it is usually quite difficult to achieve both high optical transparency and AO resistance and maintain the intrinsic thermal stability of the PI films at the same time. In the current work, we aimed to achieve the target by using the copolymerization methodology using the fluorinated dianhydride 9,9-bis(trifluoromethyl)xanthene-2,3,6,7-tetracarboxylic dianhydride (6FCDA), the fluorinated diamine 2,2-bis [4-(4-aminophenoxy)phenyl]hexafluoropropane (BDAF) and the polyhedral oligomeric silsesquioxane (POSS)-containing diamine N-[(heptaisobutyl-POSS)propyl]-3,5-diaminobenzamide (DABA-POSS) as the starting materials. The fluoro-containing monomers were used to endow the PI films with good optical and thermal properties, while the silicon-containing monomer was used to improve the AO resistance of the afforded PI films. Thus, the 6FCDA-based PI copolymers, including 6FCPI-1, 6FCPI-2 and 6FCPI-3, were prepared using a two-step chemical imidization procedure, respectively. For comparison, the analogous PIs, including 6FPI-1, 6FPI-2 and 6FPI-3, were correspondingly developed according to the same procedure except that 6FCDA was replaced by 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). Two referenced PI homopolymers were prepared from BDAF and 6FDA (PI-ref1) and 6FCDA (PI-ref2), respectively. The experimental results indicated that a good balance among thermal stability, optical transparency, and AO resistance was achieved by the 6FCDA-PI films. For example, the 6FCDA-PI films exhibited good thermal stability with glass transition temperatures (Tg) up to 297.3 °C, good optical transparency with an optical transmittance at a wavelength of 450 nm (T450) higher than 62% and good AO resistance with the erosion yield (Ey) as low as 1.7 × 10−25 cm3/atom at an AO irradiation fluence of 5.0 × 1020 atoms/cm2. The developed 6FCDA-PI films might find various applications in aerospace as solar sails, thermal control blankets, optical components and other functional materials.

Recycling of polyolefins has become a on-demand route to avoid its environmental threats. Nevertheless, drop of properties after re-extrusion necessitates use of reinforcing agents to compensate for poor mechanical properties. The incorporation of nanoparticles into plastics can boost their mechanical and rheological properties due to the hard nanocrystalline phases. This study aims to promote and identify a polyolefin-based nanocomposite by combination of TiO2 and polyhedral oligomeric silsesquioxane (POSS) at concentration of 1, 3, and 6 wt% in a twin-screw extruder. The nanocomposites were characterized for mechanical and rheological properties. Overall, the results showed that the mechanical properties were improved by adding particles up to 6 wt% loadings. The magnitude of this effect was dependent on the nanofiller weight fraction and particle size. Well-dispersion and, as a result, enhancing the viscosity, modulus, and hardness in the sample containing 3 wt% TiO2 and 3 wt%. POSS was due to the presence of hydroxyl functional groups on its surface. Glass transition temperature and crystallinity of the samples did not show a significant change due to the neutral role of nanoparticle nucleation in the matrix. [ABSTRACT FROM AUTHOR]

Dielectric materials with superb thermal and electrical properties are highly desired for high-voltage electrical equipment and advanced electronics. Here, we propose a novel strategy to improve the performance of epoxy composites by employing boron nitride nanosheets (BNNSs) and γ-glycidyl ether oxypropyl sesimoxane (G-POSS) as functional fillers. The resultant ternary epoxy composites exhibit high electrical resistivity (1.63 × 1013 Ω·cm) and low dielectric loss (<0.01) due to the ultra-low dielectric constants of cage-structure of G-POSS. In addition, a high thermal conductivity of 0.3969 W·m−1·K−1 is achieved for the epoxy composites, which is 114.66% higher than that of pure epoxy resin. This can be attributed to the high aspect ratio and excellent thermally conductive characteristics of BNNSs, promoting phonon propagation in the composites. Moreover, the epoxy composite simultaneously possesses remarkable dynamic mechanical properties and thermal stability. It is believed that this work provides a universal strategy for designing and fabricating multifunctional composites using a combination of different functional fillers. [ABSTRACT FROM AUTHOR]

Phenyl polyhedral oligomeric silsesquioxane (POSS) is modified onto the GO surface by using the strong π–π coupling between a large number of benzene rings at the end of the phenyl POSS structure and the graphite structure in the GO sheet, realizing the non-covalent functionalization of GO (POSS-GO). The POSS-GO-reinforced EP (POSS-GO/EP) composite material is prepared using the casting molding process. The surface morphology of GO before and after modification and its peel dispersion in EP are examined. Furthermore, the mechanical properties, cross-sectional morphology, and reinforcement mechanism of POSS-GO/EP are thoroughly examined. The results show that the cage-like skeleton structure of POSS is embedded between the GO layers, increasing the spacing between the GO layers and leading to a steric hindrance effect, which effectively prevents their stacking and aggregation and improves the dispersion performance of GO. In particular, the 0.4 phr POSS-GO/EP sample shows the best mechanical properties. This is because, on the one hand, POSS-GO is uniformly dispersed in the EP matrix, which can more efficiently induce crack deflection and bifurcation and can also cause certain plastic deformations in the EP matrix. On the other hand, the POSS-GO/EP fracture cross-section with a stepped morphology of interlaced "canine teeth" shape is rougher and more uneven, leading to more complex crack propagation paths and greater energy consumption. Moreover, the mechanical meshing effect between the rough POSS-GO surface and the EP matrix is stronger, which is conducive to the transfer of interfacial stress and the strengthening and toughening effects of POSS-GO. [ABSTRACT FROM AUTHOR]

The synthesis of a low dielectric constant polyimide (PI) with a polyhedral oligomeric silsesquioxane (POSS) cross-linked structure is presented. A non-planar conjugated diamine monomer (FSNH2) with two -CH=CH2 reactive groups was first synthesised in a two-step process, and then two polyimides were synthesized by PSS-Octavinyl (OVPOSS) substituted, FSNH2 and dianhydride. OVPOSS cross-linked polyimides have good thermal stability and low dielectric constant. 6FDA-FSNH2-OVPOSS(6FPI-3) can reach a minimum dielectric constant of 2.08 (108 Hz) and a dielectric loss of 0.008 (108 Hz). In addition, the cross-linked structure of the OVPOSS and polyimide chains prevents the agglomeration of OVPOSS to a certain extent and improves the tensile strength and elongation at break of the polyimides, which has great application potential in large-scale integrated circuits. [ABSTRACT FROM AUTHOR]

Most toughening methods for epoxy resins are usually used at the expense of other properties. Some polyhedral oligomeric silsesquioxanes (POSSs) with both a rigid Si-O-Si structure and flexible organic chain segments could be expected to be effective toughening agents. In this study, three reactive polyhedral oligomeric silsesquioxanes with a thiol group (OMPPS), a carboxyl group (OCOPS), and an epoxy group (OGCPS) were synthesized and characterized. They were utilized as modifiers to toughen 3-(oxiran-2-ylmethoxy)-N,N-bis(oxiran-2-ylmethyl)aniline (AFG-90MH)/4,4′-methylenebis(2-ethylaniline) (MOEA) (epoxy resin) with different molar ratios to obtain hybrid resins named OMPPS-EP-i, OCOPS-EP-j, and OGCPS-EP-k. The effects of the amount of modifier added and the length of the organic chain on the cage structure on various properties of the hybrid resins were investigated. The results show that all three modifiers show good compatibility with the epoxy resin. The hybrid resins have a low viscosity at 45~85 °C and can be cured at a low temperature (110 °C). The cured hybrid resins display improved toughness. Typically, the critical stress intensity factor (KIC) and impact strength of OGCPS-EP-0.6-C are 2.54 MPa∙m−1/2 and 19.33 kJ∙m−2, respectively, which increased by 58.75% and 22.48% compared with the pristine epoxy resin, respectively. In addition, the glass transition temperature and flexural strength of the hybrid resins are basically unchanged.

Graphene encapsulation is an attractive surface‐coating technology that can simultaneously improve the rate capability and cycle stability of nickel‐rich LiNixCoyMn1−x−yO2 (NCM). Here, carbon encapsulation with the addition of polyethylenimine (PEI) and polyhedral oligomeric silsesquioxane (POSS), which can effectively suppress access to and generation of harmful factors in the electrolyte to maximize the rate performance and cycle stability of nickel‐rich NCM, is described. The PEI‐POSS/carbon layer not only facilitates electron and lithium‐ion transport on the NCM surface but also inhibits side reactions with the electrolyte during repeated electrochemical reactions. In addition, it provides mechanical support that suppresses the formation of microcracks related to anisotropic volume change of nickel‐rich NCM secondary particles and inhibits irreversible phase transitions on surface structures by mitigating electrolyte wettability. As a result, PEI‐POSS/carbon‐encapsulated NCM exhibits a higher rate capability (84 mAh g−1 at 5 C) and cycle stability (93.5% for 100 cycles at 1 C) compared with bare NCM (0 mAh g−1 at 5 C and 78.4% for 100 cycles at 1 C). In a cycle test at 45 °C, it achieves a capacity retention of 72.6% for 100 cycles at 1 C, which is a 323% improvement in performance over that of bare NCM (22.5%). [ABSTRACT FROM AUTHOR]

The direct incorporation of Sb(V) ions into a polycondensed silsesquioxane network based on heptaisobutyl POSS units (Sb(V)-POSSs) through a corner-capping reaction is reported for the first time in this work. As a reference sample, a completely condensed monomeric Sb(III)-POSS was prepared using a similar synthetic protocol. The chemical properties of both Sb-containing POSSs were investigated with different analytical and spectroscopic techniques. The analyses confirm the success of the corner-capping reaction for both samples and indicate that an Sb(V)-POSS sample is characterized by a heterogenous multimeric arrangement with an irregular organization of POSS cages linked to Sb(V) centers, and has a more complex structure with respect to the well-defined monomeric Sb(III)-POSS. [ABSTRACT FROM AUTHOR]

Polysilsesquioxanes are extensively studied as durable and anti-adherent coatings for medical devices due to their superhydrophobic properties. However, their particular influence on the thermo-mechanical properties and biocompatibility of poly(lactic acid) (PLA)-based materials obtained by melt compounding is scarce. Herein, a facile and promising method to improve the performances of PLA for biomedical applications via the incorporation of different mass proportions of POSS nanoparticles with allyl-heptaisobutyl (AH-POSS) substituent through a melt-blending technique is proposed. The thermal, morpho-structural, mechanical properties at room (RT) and body temperatures (BT), and in vitro biocompatibility of the developed PLA/AH-POSS nanohybrids were investigated. AH-POSS nanoparticles were found to have simultaneous nucleation and plasticizing effects on the PLA nanohybrids, inducing enhanced thermal resistance and easy control of crystallinity while preserving PLA's biocompatibility. An interesting effect of AH-POSS on the mechanical properties of PLA at body temperature was observed. These results indicate the considerable potential of the PLA/AH-POSS nanohybrids obtained by melt compounding in the fabrication of biomedical devices. [ABSTRACT FROM AUTHOR]

Side effects caused by bone fractures and restrictions on bone regeneration impose an enormous economic burden on the health system of society. To overcome these limitations, tissue engineering and cell-based therapies have been proposed as alternatives to induce and promote bone healing. Still, bone regeneration disadvantages, such as limited and painful surgery, the risk of infection, nerve injury, bleeding, and function damage, have led investigators to find an alternative therapy. In some studies, bone stimulants have prompted scientists to design scaffolds with appropriate physical structure with the possibility of cell adhesion and proliferation, which plays an influential role in the regeneration and repair of bone tissue. PCL nanofiber is an absorbing candidate for the formulation of biocompatible scaffolds used in tissue engineering. To overcome these negative aspects, improve the properties of PCL nanofibers, and based on the biocompatibility and superior mechanical properties of POSS, Polyhedral Oligomeric Silsesquioxane-Polycaprolactone-Zeolite (POSS-PCL-Zeolite) nanocomposite electrospun nanofiber scaffolds were fabricated in the present study. Nanohybrids and nanofibers structures were characterized by FTIR, HNMR, XRD, SEM, EDX, and DSC techniques. We used cellular and molecular assays, including DCFH ROS detection system, gene expression (RUNX-2, Osteocalcin, Nrf2, BAX, VEGF gens), and apoptotic to demonstrate the biocompatibility and induce bone differentiation of formulated POSS-PCL-Zeolite scaffolds. The results showed the biodegradability of POSS-PCL-Zeolite Nano-scaffold and supported the nesting of mesenchymal stem cells (MSCs) and induced bone differentiation by POSS-PCL-Zeolite Nano-scaffold. [ABSTRACT FROM AUTHOR]

Abstract Background According to recent studies, electrospun Poly (Ɛ-caprolactone) (PCL) is an absorbing candidate for the formulation of biocompatible scaffolds used in tissue engineering. Tissue engineering is a set of techniques for producing or reconstructing tissue, whose primary purpose is to restore or improve the function of tissues in the human body. Tissue engineering combines the principles of materials and cell transplantation to develop alternative tissues or promote endogenous regeneration. However, this electrospun scaffold, consisting of PCL, has disadvantages such as low cell adhesion, inactivity of the surface, osteoinduction, and acidic destruction of the scaffold that causes inflammation at the implant site, often making it unsuitable implant. This study aimed to improve PCL base cellular scaffolds with the formulation of polyhedral oligomeric silsesquioxane – Polycaprolactone (POSS-PCL) nanofiber scaffolds. The present research focuses on the synthesis of nanofibers for their cell interaction features, and application in bone tissue engineering and regeneration. Results POSS/ PCL Nanocomposites with 2, 5, and 10 wt.% of POSS were synthesized in the Trichloromethane, then POSS – PCL Nanofibers were prepared by the electrospinning technique. In this study, the structures of nanohybrids and nanofibers have been evaluated by FTIR, HNMR, XRD, SEM, EDX, and DSC. The biocompatibility of formulated POSS-PCL scaffolds was detected using mesenchymal stem cells (MSCs). Then several parameters were examined, involving DCFH ROS detection system, gene expression (cell viability/apoptosis, osteogenesis potentiality, and redox molecular homeostasis. Conclusions Based on our results, POSS-PCL nano-scaffolds in comparison with PCL have shown a robust potentiality in homing, growth, and differentiation of stem cells. Graphical Abstract Synthesis of POSS-PCL Nanofibers and their potential application in Bone Regeneration.

The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labelled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity of these two compounds revealed the higher antimicrobial performances of HQ-POSS against Gram-positive and Gram-negative microorganisms, proving its broad-spectrum activity. Due to its very viscous nature, HQ-POSS was adsorbed in variable amounts on the surface of biologically active oxides to gain advantages regarding the expendability of such formulations from an applicative perspective. Titania and 5 wt% Cu on titania were used as supports. The materials 10HQ-POSS/Ti and 15HQ-POSS/5CuTi strongly inhibited the ability of Pseudomonas PS27 cells—a bacterial strain described for its ability to handle very toxic organic solvents and perfluorinated compounds—to grow as planktonic cells. Moreover, the best formulations (i.e., 10HQ-POSS/Ti and 15HQ-POSS/5CuTi) could prevent Pseudomonas PS27 biofilm formation at a certain concentration (250 μg mL−1) which greatly impaired bacterial planktonic growth. Specifically, 15HQ-POSS/5CuTi completely impaired cell adhesion, thus successfully prejudicing biofilm formation and proving its suitability as a potential antifouling agent. Considering that most studies deal with quaternary ammonium salts (QASs) with long alkyl chains (>10 carbon atoms), the results reported here on hexylimidazolium-based POSS further deepen the knowledge of QAS formulations which can be used as antifouling compounds. [ABSTRACT FROM AUTHOR]

In this study, novel open‐tubular nano‐columns with highly hydrophobic stationary phase were prepared via the surface graft polymerization of polyhedral oligomeric silsesquioxane‐methacrylate and 2‐vinylnaphthalene in a narrow capillary (i.e., 20 μm i.d. In this preparation, polyhedral oligomeric silsesquioxane‐methacrylate was used as a reactive and stable monomer while 2‐vinylnaphthalene imparts hydrophobic character for the stationary phase. Toluene and dodecanol were used as the porogenic solvent. Scanning electron microscope images of the columns showed that polyhedral oligomeric silsesquioxane and 2‐vinylnaphthalene were bound to the surface of the capillary. The chromatographic characterization of the open‐tubular columns was performed using homologous alkylbenzenes, including toluene, ethylbenzene, propylbenzene, and butylbenzene. The satisfactory separation of alkylbenzenes could be obtained using the final open‐tubular column with 17.1% of 2‐ vinylnaphthalene. Theoretical plates number up to 34000 plates/m in the isocratic mode for ethylbenzene were achieved. The open‐tubular column with various lengths was used for the separation of intact proteins in nano‐liquid chromatography, allowing a notable change in the retention time of each intact protein, including ribonuclease A, Lysozyme, and α‐Chymotryp A. The final open‐tubular column was then applied to the peptide separation of trypsin‐digested cytochrome C. It was shown that the open‐tubular column yielded a high‐resolution analysis of peptides, providing a high peak capacity of up to 1000. [ABSTRACT FROM AUTHOR]

The effect of octaisobutyl-polyhedral oligomeric silsesquioxane (OIB-POSS) as a nanosized reinforcement on the cure kinetics, crosslinking density, and mechanical properties of styrene-butadiene rubber (SBR) nanocomposites was examined in this study. For this purpose, SBR compounds with various OIB-POSS nanoparticle loadings at 1, 3, and 5 phr were prepared and their results were compared with a reference compound without OIB-POSS. When 1 phr of OIB-POSS was added to the rubber matrix, the elongation at break values and tensile strength of the corresponding nanocomposite increased by 24.1% and 29.2% compared to the reference sample, respectively. The presence of OIB-POSS nanoparticles and their random distribution in the SBR matrix was confirmed by transmission electron microscopy. The crosslinking density of nanocomposites was calculated by the Flory-Rehner method and a decrease was observed with the addition of OIB-POSS nanoparticles. In addition, thermal aging process as 70 °C for 70 h was applied to vulcanized samples. It was noted that the mechanical properties of SBR/OIB-POSS nanocomposites remarkably improved, whereas their crosslinking densities gradually decreased after thermal aging. [ABSTRACT FROM AUTHOR]

Fluorosilicone rubber (F-LSR) is a promising material that can be applied in various cutting-edge industries. However, the slightly lower thermal resistance of F-LSR compared with that of conventional PDMS is difficult to overcome by applying nonreactive conventional fillers that readily agglomerate owing to their incompatible structure. Polyhedral oligomeric silsesquioxane with vinyl groups (POSS-V) is a suitable material that may satisfy this requirement. Herein, F-LSR-POSS was prepared using POSS-V as a chemical crosslinking agent chemically bonded with F-LSR through hydrosilylation. All F-LSR-POSSs were successfully prepared and most of the POSS-Vs were uniformly dispersed in the F-LSR-POSSs, as confirmed by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) measurements. The mechanical strength and crosslinking density of the F-LSR-POSSs were determined using a universal testing machine (UTM) and dynamic mechanical analysis (DMA), respectively. Finally, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements confirmed that the low-temperature thermal properties were maintained, and the heat resistance was significantly improved compared with conventional F-LSR. Eventually, the poor heat resistance of the F-LSR was overcome with three-dimensional high-density crosslinking by introducing POSS-V as a chemical crosslinking agent, thereby expanding the potential fluorosilicone applications. [ABSTRACT FROM AUTHOR]

Nanoparticles of zinc oxide (ZnO), polyhedral oligomeric silsesquioxane (POSS), and their hybrids were added to polylactic acid (PLA) using solution casting process at different weight percentages of the nanoparticles (1, 3, and 5 wt%) to form developed nanocomposites for food packaging applications. According to FTIR and XRD studies, both nanoparticles displayed fair chemical interactions with the PLA matrix. Furthermore, morphological investigations (SEM‐EDS) revealed that POSS, ZnO, and their hybrids were uniformly dispersed into the matrix despite some microaggregations at 5 wt% of nanoparticles, especially for those containing POSS. Moreover, adding 1 wt% of POSS to PLA increased its tensile strength and modulus by 20% and 149%, respectively, while decreasing the elongation‐at‐break by 54%. In addition, the tensile strength, tensile modulus, and elongation‐at‐break of PLA all increased by 7.5%, 28.7%, and 162%, respectively, with the addition of 1 wt% ZnO. Contact angle and surface free energy experiments demonstrated that after incorporating ZnO and POSS into the PLA matrix, the hydrophobicity of the samples increased, and POSS nanoparticles could minimize bacterial adherence effectively. In addition to the antibacterial properties of ZnO and POSS nanoparticles, increasing the concentration of hybrid nanoparticles up to 5 wt% expanded the bacteria's inhibitory zone, particularly in the case of Gram‐positive bacteria (Staphylococcus aureus). Finally, the hybrid nanocomposites exhibited both balanced mechanical characteristics and promising antibacterial activity compared with those with ZnO and POSS alone. [ABSTRACT FROM AUTHOR]

Low-dielectric-constant (low-k) materials are an indispensable part of microprocessors as they can alleviate electronic crosstalk, charge build-up, and signal propagation delay. However, existing low-k materials usually have k values higher than 2 and inferior thermo-mechanical properties, which restrict the development of microelectronic devices. Although we have recently discovered that larger polyhedral oligomeric silsesquioxanes (POSS) are useful building blocks for fabricating advanced ultra-low-k materials, it remains to be seen whether a POSS cage and linker could be leveraged to tune the structure-property of the materials and create ultra-low-k materials with improved comprehensive properties. Herein, we propose a series of POSS-based hybrid materials (i.e., c-TnPBn and c-TnFn, n = 8, 10, and 12) that consist of distinct POSS cages and linkers. When the linker is kept identical, the gradual enlargement of the POSS cage enhances the porosity/free volume fraction of materials, resulting in quasi-linearly reduced k values for the resulting materials (k = 1.93 for c-T12PB12, 2.14 for c-T12F12). Meanwhile, the materials’ comprehensive properties can be significantly improved by increasing the POSS cage size or varying the linker’s length and type. As a result, ultra-low-k materials with good processability, low surface roughness (< 0.40 nm), excellent thermostability (> 480 °C), mechanical properties (elastic modulus > 2.5 GPa), and hydrophobicity have been obtained, and the low-k values can be maintained under high temperature (e.g., 300 °C) and wet condition. This work reveals the critical contribution of POSS cage size and linker to the structure and properties of POSS-based low-k materials and offers promising materials for the future of the microelectronic industry.

Dielectric materials with superb thermal and electrical properties are highly desired for high-voltage electrical equipment and advanced electronics. Here, we propose a novel strategy to improve the performance of epoxy composites by employing boron nitride nanosheets (BNNSs) and γ-glycidyl ether oxypropyl sesimoxane (G-POSS) as functional fillers. The resultant ternary epoxy composites exhibit high electrical resistivity (1.63 × 1013 Ω·cm) and low dielectric loss (−1·K−1 is achieved for the epoxy composites, which is 114.66% higher than that of pure epoxy resin. This can be attributed to the high aspect ratio and excellent thermally conductive characteristics of BNNSs, promoting phonon propagation in the composites. Moreover, the epoxy composite simultaneously possesses remarkable dynamic mechanical properties and thermal stability. It is believed that this work provides a universal strategy for designing and fabricating multifunctional composites using a combination of different functional fillers.

Phenyl polyhedral oligomeric silsesquioxane (POSS) is modified onto the GO surface by using the strong π–π coupling between a large number of benzene rings at the end of the phenyl POSS structure and the graphite structure in the GO sheet, realizing the non-covalent functionalization of GO (POSS-GO). The POSS-GO-reinforced EP (POSS-GO/EP) composite material is prepared using the casting molding process. The surface morphology of GO before and after modification and its peel dispersion in EP are examined. Furthermore, the mechanical properties, cross-sectional morphology, and reinforcement mechanism of POSS-GO/EP are thoroughly examined. The results show that the cage-like skeleton structure of POSS is embedded between the GO layers, increasing the spacing between the GO layers and leading to a steric hindrance effect, which effectively prevents their stacking and aggregation and improves the dispersion performance of GO. In particular, the 0.4 phr POSS-GO/EP sample shows the best mechanical properties. This is because, on the one hand, POSS-GO is uniformly dispersed in the EP matrix, which can more efficiently induce crack deflection and bifurcation and can also cause certain plastic deformations in the EP matrix. On the other hand, the POSS-GO/EP fracture cross-section with a stepped morphology of interlaced “canine teeth” shape is rougher and more uneven, leading to more complex crack propagation paths and greater energy consumption. Moreover, the mechanical meshing effect between the rough POSS-GO surface and the EP matrix is stronger, which is conducive to the transfer of interfacial stress and the strengthening and toughening effects of POSS-GO.

Thermal analysis is an effective mean to study the crystallization of polymers. Fast scanning chip calorimetry (FSC) has ultra-high cooling and heating rate and plays an important role in the study of crystallization behavior. The crystallization kinetics of poly (l-lactic acid) (PLLA) with amino polyhedral oligomeric silsesquioxane (POSS-NH2) and polyethylene glycol-grafted POSS (POSS-PEG) was investigated by traditional differential scanning calorimetry (DSC) and FSC. The results show that the addition of POSS-PEG has a better promoting effect on the crystallization rate of PLLA than POSS-NH2. And there are two differences between the results of FSC and DSC: firstly, FSC can effectively avoid the nucleation and crystallization behavior in the cooling process and ensure that the crystallization process occurs completely in the isothermal stage, while DSC cannot; second, the measured crystallization rate by FSC is lower than the traditional DSC data. In a word, POSS plays a role of nucleation agent in PLLA crystallization, and PEG as nucleation accelerator further improves the crystallization rate; FSC can effectively avoid the nucleation and crystallization in the cooling and heating process. [ABSTRACT FROM AUTHOR]

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In this study, polyhedral oligomeric silsesquioxane (POSS) based giant triblock molecules with precisely defined regio‐configuration are modularly prepared through highly efficient coupling reactions. The length of the linker connecting neighboring nanoparticles is elaborately designed to regulate the geometric constraints. The triblock molecules adopt a folded packing during phase separation, and the regio‐configuration imparts direct influence on the self‐assembly behaviors. The ortho‐isomers form periodic structures with a larger domain size, larger interfacial curvature, and enhanced phase stability. The regio‐effect is closely related to the length and symmetry of the linker. As the linker extends, the neighboring particles gradually decouple, and the regio‐effect diminishes. The symmetry of the linker shows an even more profound impact. This work quantitatively scrutinized the role of the linker, opening an avenue for engineering the assembled structures with molecular precision. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: According to recent studies, electrospun Poly (Ɛ-caprolactone) (PCL) is an absorbing candidate for the formulation of biocompatible scaffolds used in tissue engineering. Tissue engineering is a set of techniques for producing or reconstructing tissue, whose primary purpose is to restore or improve the function of tissues in the human body. Tissue engineering combines the principles of materials and cell transplantation to develop alternative tissues or promote endogenous regeneration. However, this electrospun scaffold, consisting of PCL, has disadvantages such as low cell adhesion, inactivity of the surface, osteoinduction, and acidic destruction of the scaffold that causes inflammation at the implant site, often making it unsuitable implant. This study aimed to improve PCL base cellular scaffolds with the formulation of polyhedral oligomeric silsesquioxane – Polycaprolactone (POSS-PCL) nanofiber scaffolds. The present research focuses on the synthesis of nanofibers for their cell interaction features, and application in bone tissue engineering and regeneration. Results: POSS/ PCL Nanocomposites with 2, 5, and 10 wt.% of POSS were synthesized in the Trichloromethane, then POSS – PCL Nanofibers were prepared by the electrospinning technique. In this study, the structures of nanohybrids and nanofibers have been evaluated by FTIR, HNMR, XRD, SEM, EDX, and DSC. The biocompatibility of formulated POSS-PCL scaffolds was detected using mesenchymal stem cells (MSCs). Then several parameters were examined, involving DCFH ROS detection system, gene expression (cell viability/apoptosis, osteogenesis potentiality, and redox molecular homeostasis. Conclusions: Based on our results, POSS-PCL nano-scaffolds in comparison with PCL have shown a robust potentiality in homing, growth, and differentiation of stem cells. Synthesis of POSS-PCL Nanofibers and their potential application in Bone Regeneration. [ABSTRACT FROM AUTHOR]

In this work, carboxymethyl cellulose (CMC)/montmorillonite (MMT) bio-nanocomposite films were prepared by intercalating MMT with polyhedral oligomeric silsesquioxane (POSS) to promote the interfacial interactions between CMC and MMT and overcome limitations of CMC such as its moisture barrier property, thermal, and mechanical properties with maintaining its transparency, biocompatibility, and film-forming ability, etc. POSS combined with ammonium and imidazolium groups (POSS-ammonium and POSS-imidazolium) were prepared by the hydrolysis of organic silane compounds and intercalated into MMT via an ion-exchange reaction. MMT intercalated with POSS-ammonium and POSS-imidazolium are designated as MOAP and MOIP, respectively. MMT modified with POSS-imidazolium (MOIP) was adequately dispersed in the polymer matrix owing to the increased gap between the MMT layers and electrostatic interaction between POSS at the MMT edge and carboxylate moieties on CMC chain. The good compatibility and interaction between MOIP and CMC as well as higher thermal stability of heterocyclic compound in POSS-imidazolium endowed the bionanocomposite films with excellent mechanical properties and thermal stability. Furthermore, UV-barrier, moisture barrier, antibacterial, and antioxidant properties of the CMC bionanocomposite films were effectively improved with the introduction of MOIP. [ABSTRACT FROM AUTHOR]

Poly (l-lactic acid) (PLLA) and polycarbonate (PCL) grafted Monoamino-Polyhedral oligomeric silsesquioxane (POSS-NH2) (POSS-PLLA and POSS-PCL) by ring-opening polymerization of L-lactide (L-LA) and caprolactone (ε-CL) from POSS-NH2 were obtained in this work. The fourier transform infrared spectrometer (FTIR) results show that the stretching vibration peaks of -C(O)-NH- of POSS-PLLA and POSS-PCL appears at 1650 cm−1 and 1645 cm−1. The crystal diffraction peaks of POSS-PLLA at 22°, 16.7° and 19° are same as the peak positions of PLLA; POSS-PCL at 21.7° 23.7° are same as the peak positions of PCL by X-Ray diffraction (XRD). Both FTIR and XRD results indicate that the grafted products are synthesized successfully. Then, the different contents of POSS-PLLA, POSS-PCL and purchased POSS-polyethylene glycol (POSS-PEG) were blended with PLLA/Poly (d-lactic acid) (PDLA) (with the mass ratio of 1:1) to prepare ternary blends with different contents of polymer grafted POSS. The effects of POSS-PLLA, POSS-PCL and POSS-PEG on the crystallization behavior of PLLA/PDLA were investigated. The results show that compared with POSS-PCL and POSS-PLLA, POSS-PEG enhances the crystallization ability of PLLA/PDLA, and promotes the formation of stereocomplex (SC); on the contrary, POSS-PCL and POSS-PLLA inhibit the formation of SC. [ABSTRACT FROM AUTHOR]

Dry eye is a common ocular disease that results in discomfort and impaired vision, impacting an individual's quality of life. A great number of drugs administered in eye drops to treat dry eye are poorly soluble in water and are rapidly eliminated from the ocular surface, which limits their therapeutic effects. Therefore, it is imperative to design a novel drug delivery system that not only improves the water solubility of the drug but also prolongs its retention time on the ocular surface. Herein, we develop a copolymer from mono-functional POSS, PEG, and PPG (MPOSS-PEG-PPG, MPEP) that exhibits temperature-sensitive sol-gel transition behavior. This thermo-responsive hydrogel improves the water solubility of FK506 and simultaneously provides a mucoadhesive, long-acting ocular delivery system. In addition, the FK506-loaded POSS hydrogel possesses good biocompatibility and significantly improves adhesion to the ocular surface. In comparison with other FK506 formulations and the PEG-PPG-FK506 (F127-FK506) hydrogel, this novel MPOSS-PEG-PPG-FK506 (MPEP-FK506) hydrogel is a more effective treatment of dry eye in the murine dry eye model. Therefore, delivery of FK506 in this POSS hydrogel has the potential to prolong drug retention time on the ocular surface, which will improve its therapeutic efficacy in the management of dry eye.

Polyimide (PI) is considered one of the most promising candidate materials for the microelectronics and wireless communication industries. Nevertheless, the relatively high dielectric constant of PI has become a significant obstacle, constraining its utilization in the realm of microelectronics. Herein, novel PI nanocomposite films were fabricated by incorporating covalent organic frameworks (COFs) and their functionalized counterparts (COF@POSS and COF@DTF) through post-synthetic modification. Among all PI nanocomposites films, PI/COF@POSS nanocomposite film including 2 wt% COF@POSS achieved the lowest dielectric constant (2.41) and dielectric loss (0.0076). These values represented a reduction of 22.5 % and 24 % compared to pure PI, respectively. The decrease in dielectric constant is ascribed to the combined influence of the porous structure of COF and the augmentation in free volume fraction caused by the steric hindrance of POSS. Additionally, the tensile strength of the PI/COF@POSS and PI/COF@DTF nanocomposite films increased up to 121.1 MPa and 112.0 MPa, representing a 95 % and 80 % improvement over pure PI, respectively. Furthermore, the introduction of COFs functionalized with POSS and DTF significantly enhanced the hydrophobicity of PI nanocomposite films. The combination of porous organic nanofillers with surface functionalization offers a feasible route to create low-k PI nanocomposite films with improved mechanical properties and hydrophobicity. The PI nanocomposite films with functional covalent organic frameworks exhibited the decreased dielectric constant and dielectric loss with improved mechanical performance. [Display omitted] • The novel low dielectric PI films were obtained by adding functional COFs. • PI/COF@POSS films achieved the lowest dielectric constant of 2.41. • The maximum tensile strength of PI/COF@POSS films reaches 121.1 MPa. • The hydrophobicity of PI/COF@DTF films is greatly improved. [ABSTRACT FROM AUTHOR]

• A novel POSS antioxidant based on amide-linked hindered phenols (HPAm-POSS) was synthesized. • The novel antioxidant has a molecular weight of 2962.7 and contains 2.70 mmol/g of hindered phenolic groups. • HPAm-POSS significantly improves the thermal-oxidative stability of PA66 in thermal aging and processing. • HPAm-POSS exhibits higher anti-extraction performance than Irganox 1098 due to its high molecular weight. A novel polyhedral oligomeric sesquisiloxane (POSS) antioxidant based on amide-linked hindered phenols (HPAm-POSS) was successfully synthesized via a nucleophilic substitution reaction. The chemical structure of HPAm-POSS was characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), MALDI-TOF mass spectrometry (MS), and thermogravimetric analysis (TGA). The antioxidative efficiency of HPAm-POSS in polyamide 6,6 (PA66) was investigated by accelerated thermal aging tests, processing experiments, and extraction experiments and compared with a commercial hindered phenol antioxidant, Irganox 1098, at an equivalent concentration of active hindered phenolic stabilizer groups. The results showed that the thermal-oxidative stability of PA66 materials was significantly improved by the incorporation of either HPAm-POSS or Irganox 1098. Although the antioxidant efficiency of HPAm-POSS in the long-term accelerated thermal aging of PA66 at 150 °C in an air oven is slightly lower than that of Irganox 1098, HPAm-POSS is slightly more effective than Irganox 1098 in inhibiting the degradation of PA66 during multiple processing. Notably, HPAm-POSS exhibited higher anti-extraction properties in PA66 due to its higher molecular weight and lower migration ratio. Consequently, PA66/0.35 %HPAm maintains thermo-oxidative stability even after being extracted with organic media such as ethanol, toluene, or ethylene glycol, whereas PA66/0.30 %1098 is highly susceptible to thermo-oxidative degradation due to the physical loss of Irganox 1098 by extraction. [ABSTRACT FROM AUTHOR]

• Cost-effective disc-shaped supramolecular nanosheets are successfully constructed. • POM(W)-POSS(ibu-Li) supramolecular nanosheets enhance thermal properties of EP. • Trace POM(W)-POSS(ibu-Li) supramolecular apparently mitigates fire hazards of EP. • The nano-multielement nanosheets extend the application scope of EP in aerospace. Obtaining maximum comprehensive performance enhancement at the least-cost has always been the core goal of additive modification to solve engineering application problems. Intended to tackle industrial practical application puzzles that it is challenging to simultaneously achieve efficient flame retardant and smoke suppression epoxy resin (EP). Herein, unique two-dimensional disc-shaped polyhedral oligomeric silsesquioxane/polyoxometalate (POM(W)-POSS(ibu-Li)) Janus supramolecular nanosheets were synthesized via simple one-pot method adopting laboratory-made lithium-containing hepta-isobutyl-POSS (ibu-Li-POSS) and low-cost H 3 PW 12 O 40 as raw materials. The synthesized POM(W)-POSS(ibu-Li) contained various flame retardant and smoke suppression elements such as P, W and Si. Incorporating 2 wt% POM(W)-POSS(ibu-Li) into EP distinctly decreased the total heat release (THR), peak of smoke production rate (p-SPR) and CO production rate (p-COP) by 28.1 %, 51.6 % and 28.9 %, respectively. The dilemmas of inherent flammability of EP were completely penetrated. The successful application of two-dimensional disc-shaped POM(W)-POSS(ibu-Li) supramolecular nanosheets will inevitably resulted in the frontier upsurge in the development of cost-effective POSS derivatives as superior nano-scale flame retardants and smoke suppressants. [Display omitted] [ABSTRACT FROM AUTHOR]

Rare earth luminescent complexes encounter defects such as poor thermal stability, poor dispersibility, and easy quenching of fluorescence emission by water in practical applications. To improve these defects, we innovatively propose using polyhedral oligomeric silsesquioxane (POSS) to enhance the performance of rare earth complexes. We designed and prepared POSS-MAA-EuL composite materials. POSS is modified with long chains containing -COOH functional groups, allowing it to bind with rare earth complexes through coordination interactions. Experimental results have shown that the combination of POSS not only improves the dispersibility of rare earth complexes, but also enhances their thermal stability. It is worth noting that the binding of POSS endows rare earth complexes with the ability of resisting fluorescence emission quenching by water. When the same volume of deionized water is added (2000 μL), the fluorescence of rare earth complex is almost completely quenched, with a quenching efficiency of 99.0 %, while the quenching efficiency of POSS-MAA-EuL is only 39.2 %. There are few reports on improving the water quenching resistance of rare earth luminescent complexes by combining with POSS. Therefore, this work provides a new way to improve the performance of rare earth complexes. [Display omitted] • The EuL complex modified by POSS-MAA exhibits a layered cubic morphology. • The composite of POSS-MAA enhances the dispersibility and thermal stability of EuL complexes. • POSS-MAA-EuL composite material exhibits resistance to water luminescent quenching. [ABSTRACT FROM AUTHOR]

The direct incorporation of Sb(V) ions into a polycondensed silsesquioxane network based on heptaisobutyl POSS units (Sb(V)-POSSs) through a corner-capping reaction is reported for the first time in this work. As a reference sample, a completely condensed monomeric Sb(III)-POSS was prepared using a similar synthetic protocol. The chemical properties of both Sb-containing POSSs were investigated with different analytical and spectroscopic techniques. The analyses confirm the success of the corner-capping reaction for both samples and indicate that an Sb(V)-POSS sample is characterized by a heterogenous multimeric arrangement with an irregular organization of POSS cages linked to Sb(V) centers, and has a more complex structure with respect to the well-defined monomeric Sb(III)-POSS.

Development of artificial biomaterials by mimicking extracellular matrix of bone tissue is a promising strategy for bone regeneration. Hydrogel has emerged as a type of viable substitute, but its inhomogeneous networks and weak mechanics greatly impede clinical applications. Here, a dual crosslinked gelling system is developed with tunable architectures and mechanics to promote osteogenic capacity. Polyhedral oligomeric silsesquioxane (POSS) is designated as a rigid core surrounded by six disulfide‐linked PEG shells and two 2‐ureido‐4[1H]‐pyrimidinone (UPy) groups. Thiol‐disulfide exchange is employed to fabricate chemical network because of the pH‐responsive "on/off" function. While self‐complementary UPy motif is capable of optimizing local microstructure to enhance mechanical properties. Taking the merits of biocompatibility and high‐mechanics in periodontal ligament stem cells (PDLSCs) proliferation, attachment, and osteogenesis, hybrid hydrogel exhibits outstanding osteogenic potential both in vitro and in vivo. Importantly, it is the first time that a key epigenetic regulator of ten‐eleven translocation 2 (Tet2) is discovered to significantly elevate the continuously active the WNT/β‐catenin through Tet2/HDAC1/E‐cadherin/β‐catenin signaling cascade, thereby promoting PDLSCs osteogenesis. This work represents a general strategy to design the hydrogels with customized networks and biomimetic mechanics, and illustrates underlying osteogenic mechanisms that will extend the design rationales for high‐functional biomaterials in tissue engineering. [ABSTRACT FROM AUTHOR]

The common disease of articular cartilage is osteoarthritis, which can be diagnosed with the degradation of the articular cartilage a well as formation of osteophytes, subchondral sclerosis, synovial inflammation and ultimate loss of joint function. Due to the lack of articular cartilage regeneration as well as shortage of appropriate treatment, tissue engineering has been widely used to fabricate hybrid scaffolds for supporting cartilage tissue regeneration using 3D fabrication and design techniques. In this study a 3D scaffold was designed using polycaprolactone (PCL)/poly(lactic‐co‐glycolic acid) (PLGA) biomaterial inks. Moreover, in order to achieve mechanical consistency and optimize the printing process, different concentrations of polyhedral oligomeric silsesquioxane (POSS) nanoparticles including 0, 3 and 5 (% w/v) were added. The cartilage derived extracellular matrix (ECM) particles were used as the filler to improve hydrophilicity, optimal porosity formation, optimal mechanical properties and print resolution. The samples were evaluated in terms of morphology, thermal properties, physicochemical structure, hydrophilicity, mechanical properties, biodegradation as well as thermal and cell culture study. Results showed that the compressive modulus of the PCL/PLGA/20%ECM/3%POSS 3D printed scaffolds was higher than other scaffolds. By adding 20% (w/w) ECM to the basic biomaterial ink viscosity of the biomaterial ink, porosity and water uptake were increased significantly. The 3D printed scaffold containing PCL/PLGA/5%POSS/20%ECM components demonstrated high biocompatibility as well as cell viability. Therefore, it was concluded that 3% POSS accompanying 20% ECM addition was the most suitable bioink composition for fabricating the most biocompatible and applicable scaffold for cartilage tissue engineering applications. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxane (POSS) is commonly used to lower the dielectric constant of polyimide (PI), but the toughness generally deteriorates. In this paper, trifluoropropyl POSS (FPOSS) is surprisingly found to impart superior dielectric constant and toughness to PI, even though the phase separation and aggregation of FPOSS are observed due to the thermodynamical immiscibility between FPOSS and PI. The dielectric constant of FPOSS/PI with 2.0 wt% FPOSS is reduced to 2.47 from 3.17. Furthermore, the tensile energy to break of FPOSS/PI is unexpectedly increased to 10.2 MJ/m3 from 3.3 MJ/m3, indicating the great improvement in toughness. The toughening mechanism is ascribed to the debonding of FPOSS aggregates from PI matrix with a void growth during tensile test. Meanwhile, lateral coalescence of the voids is avoided due to the adequate inter‐aggregate distance when the width of the ligaments between the aggregates decreases with elongation of matrix. [ABSTRACT FROM AUTHOR]

The efficient and accurate separation of immunoglobulin G (IgG) plays a vital role for disease diagnosis and therapy, but it is always hampered by the huge geometric size and complex structure of IgG. In this work, an amorphous Fe/Co bimetallic organic framework (denoted as PMOF-Fe/Co) is fabricated for IgG separation, with octa-carboxyl polyhedral oligomeric silsesquioxane (OCPOSS) as modulator for the first time. Benefiting from the rigid nanostructure and competitive coordination of OCPOSS, the aperture of PMOF-Fe/Co is enlarged to ∼20 nm along with the generation of enormous structural defects, which enables the accommodation of protein species with high molecular weights and large sizes. OCPOSS is also found exerting a positive impact on mediating the specific recognition and adsorption ability of PMOF-Fe/Co towards IgG through metal affinity, hydrophilic and hydrophobic interactions. Consequently, the multimode and multivalent affinity of PMOF-Fe/Co gives rise to an extraordinary adsorption capacity (2691.7 mg g -1 ) and satisfactory practical application performance. This study is convinced to provide a simple avenue for the efficient separation of specific large-sized proteins, as well as the engineering of abiotic affinity reagents with compositional and architectural complexity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Polyhedral oligomeric silsesquioxane (POSS) is a 3D, cage-like nanoparticle with an inorganic Si-O-Si core and eight tunable corner functional groups. Its well-defined structure grants it distinctive physical, chemical, and biological properties and has been widely used for preparing high-performance materials. Recently, click chemistry has enabled the synthesis of various functional POSS-based materials for diverse biomedical applications. This article reviews the recent applications of POSS-based materials in the biomedical field, including cancer treatment, tissue engineering, antibacterial use, and biomedical imaging. Representative examples are discussed in detail. Among the various POSS-based applications, cancer treatment and tissue engineering are the most important. Finally, this review presents the current limitations of POSS-based materials and provides guidance for future research., (© 2024 Wiley‐VCH GmbH.)

In recent years, fluorescent organic–inorganic hybrid nanomaterials have received much interest as potential fluorescent sensor materials. In this study, fluorescent organic–inorganic hybrid nanomaterials (POSS@ANT) were created using polyhedral oligomeric silsesquioxane as the precursor and 9,10‐bromoanthracene as the monomer. The morphology and composition of POSS@ANT, as well as its pore characteristics and fluorescence properties were studied. POSS@ANT displayed steady fluorescence emission at an excitation wavelength of 374 nm. Next, a β‐carotene fluorescence sensor was developed using the capacity of β‐carotene to quench the fluorescence of POSS@ANT. The quenching process is linked to acceptor electron transfer and energy transfer, and the sensor has a high selectivity for β‐carotene. This β‐carotene fluorescence analysis method that we established has a linear range of 0.2–4.3 mg/L and a detection limit of 0.081 mg/L. Finally, it was used to quantify β‐carotene in health products, the recovery rate was 91.1–109.9%, the relative standard deviation (RSD) was 2.2–4.3%, and the results were comparable with the results of high‐performance liquid chromatography. The approach is reliable and can be used to determine β‐carotene in health products. [ABSTRACT FROM AUTHOR]

[Display omitted] High-capacity and rapid adsorption of organic micropollutants (OMPs) from water by adsorbents remain a great significance in water treatment. Recently, porous organic polymers with high surface areas, tunable nanopores and easy-to-modify skeletons are promising new generation of adsorbents. Here, a series of silsesquioxane-crosslinked conjugated microporous polymers (PcCMPs) with high surface areas and well-defined nanopores are developed via a molecular expansion strategy for removing OMPs from water. Among these PcCMPs , PcCMP-2E exhibited the highest Brunauer–Emmett–Teller surface area up to 2518 m2 g−1. The maximum adsorption capacities of bisphenol A (BPA) of PcCMPs are ranging from 485.44 to 628.93 mg g−1. Specially, >93.5% of BPA could be removed even through a thin layer filtration device composed of PcCMPs , which can be regenerated well using a mild washing procedure. PcCMPs also exhibit extraordinary adsorption to a variety of OMPs, such as tetracycline (226.99 mg g−1), 1-naphthylamine (290.07 mg g−1), 2-naphthol (213.87 mg g−1), 2,4-dichlorophenol (183.85 mg g−1) and p -nitrophenol (360.24 mg g−1). This work provides a new strategy to design porous adsorbents with high adsorption capacity and fast adsorption rate for water treatment. [ABSTRACT FROM AUTHOR]

Perfluoropolyethers (PFPE) are commercially available non-flammable short chain polymeric liquids. End-functionalized PFPE chains solvate lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and these mixtures can be used as electrolytes for lithium (Li) batteries. Here we synthesize and characterize a new class of solid PFPE electrolytes. The electrolytes are made by either thermal or UV crosslinking PFPE chains with urethane methacrylate end-groups. For the synthesis of thermally crosslinked electrolytes, polyhedral oligomeric silsesquioxane (POSS) with organic acrylopropyl groups was used as crosslinker agent, while for UV cured electrolytes a photoinitiatior was used. We present thermal, morphological, and electrical data of the solid electrolytes. We compare these properties with those of the two parent liquids (PFPE with urethane methacrylate end-groups and POSS with acrylopropyl groups) mixed with LiTFSI. The solubility limit of LiTFSI in the PFPE-based solids is higher than that in the liquids. The conductivity data are analyzed using the Vogel–Tamman–Fulcher equation. The concentration of effective charge carriers is a strong function of the nature of the solvent (solid versus liquid) whereas the activation energy is neither a strong function of the nature of the solvent nor salt concentration.

Perfluoropolyethers (PFPE) are commercially available non-flammable short chain polymeric liquids. End-functionalized PFPE chains solvate lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and these mixtures can be used as electrolytes for lithium (Li) batteries. Here we synthesize and characterize a new class of solid PFPE electrolytes. The electrolytes are made by either thermal or UV crosslinking PFPE chains with urethane methacrylate end-groups. For the synthesis of thermally crosslinked electrolytes, polyhedral oligomeric silsesquioxane (POSS) with organic acrylopropyl groups was used as crosslinker agent, while for UV cured electrolytes a photoinitiatior was used. We present thermal, morphological, and electrical data of the solid electrolytes. We compare these properties with those of the two parent liquids (PFPE with urethane methacrylate end-groups and POSS with acrylopropyl groups) mixed with LiTFSI. The solubility limit of LiTFSI in the PFPE-based solids is higher than that in the liquids. The conductivity data are analyzed using the Vogel–Tamman–Fulcher equation. The concentration of effective charge carriers is a strong function of the nature of the solvent (solid versus liquid) whereas the activation energy is neither a strong function of the nature of the solvent nor salt concentration.

In this work, octamercapto polyhedral oligomeric silsesquioxane (POSS-8SH) and octaphenol polyhedral oligomeric silsesquioxane (POSS-8Phenol) were successfully synthetized. POSS-8Phenol was added into the synthesis process of liquid thermoset phenolic resin (PR) to obtain POSS-modified phenolic resin (POSS-PR). Chemical structures of POSS-8SH, POSS-8Phenol, and POSS-PR were confirmed by FTIR and 1H-NMR. TG and DTG analysis under different atmosphere showed that char yield of POSS-PR at 1,000°C increased from 58.6% to 65.2% in N2, which in air increased from 2.3% to 26.9% at 700°C. The maximum pyrolysis temperature in air increased from 543°C to 680°C, which meant better anti-oxidation properties. XRD results confirmed both POSS-8Phenol and POSS-PR-generated crystalline SiO2 in air, which could explain the improvement of anti-oxidation properties. SEM showed that the POSS-PR had phase separation during curing process. Finally, carbon fiber fabric-reinforced POSS-PR (C-POSS-PR) was prepared to verify the anti-oxidation properties of POSS-PR.

Chemical reactions based on the characteristics of silicon-oxygen bonds and different conditions are important methods to construct new organic/inorganic siloxane functional materials with very different structures and unique properties, which have aroused widespread attention in the academic community. The new silicon-oxygen functional materials have both organic/inorganic compound properties, and are widely used in many fields for their good biocompatibility, high and low temperature resistance, and electrical insulation properties. The research fields and development status of the design, synthesis and application of siloxane compounds were reviewed in this paper, focusing on the design and synthesis methods of linear structure (one-dimensional structure), nonlinear structure (two-dimensional structure), polyhedral oligomeric silsesquioxane compounds (three-dimensional structure) and organic/inorganic hybrid siloxane compounds, and the application progress of siloxane compounds in biomedicine, aerospace, functional materials and tertiary oil recovery will be promoted by studying stretchable polysiloxane elastomer, siloxane compound coating, new silicone functional materials for oil displacement and so on.

[Display omitted] • The effect of molecular structure on the dispersion of POSS in EVA was investigated. • Effect of POSS dispersion on the mechanical properties of EVA. • Influence of POSS dispersibility on flame retardant properties of EVA. • The reasons for the differences in EVA performance are explored. Improving the flame retardancy of ethylene–vinyl acetate copolymer (EVA) while maintaining its mechanical properties is critical for EVA applications. Polyhedral oligomeric silsesquioxane (POSS) can be a molecular structure designed to improve the flame retardancy of polymers while minimizing damage to the mechanical properties of polymers. In this study, two types of POSS with the same chemical structure but different spatial structures, which are named cage octaphenyl POSS (OPS) and ladder polyphenyl silsesquioxane (PPSQ) are prepared. The miscibility and dispersibility of these two types of POSS in the EVA matrix and their effects on mechanical properties, dielectric properties, and fire behaviors are also investigated. Compared to OPS-based EVA composite, the PPSQ with ladder structure has good miscibility and dispersion state in EVA matrix, obtaining better toughness, dielectric properties, and flame retardancy under cone calorimeter test. However, OPS-based EVA composite obtains superior flame retardancy than that of PPSQ-based EVA composite under small fire test (limiting oxygen index and UL-94 vertical burning tests). The mechanism of these two separate flame-retardant performances under various scenarios is explored. A novel flame-retardant model is proposed, as well as a new understanding of the role of POSS in EVA combustion. This study provides powerful guidance for obtaining EVA composites with excellent flame retardant and mechanical properties. [ABSTRACT FROM AUTHOR]

The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labelled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity of these two compounds revealed the higher antimicrobial performances of HQ-POSS against Gram-positive and Gram-negative microorganisms, proving its broad-spectrum activity. Due to its very viscous nature, HQ-POSS was adsorbed in variable amounts on the surface of biologically active oxides to gain advantages regarding the expendability of such formulations from an applicative perspective. Titania and 5 wt% Cu on titania were used as supports. The materials 10HQ-POSS/Ti and 15HQ-POSS/5CuTi strongly inhibited the ability of Pseudomonas PS27 cells—a bacterial strain described for its ability to handle very toxic organic solvents and perfluorinated compounds—to grow as planktonic cells. Moreover, the best formulations (i.e., 10HQ-POSS/Ti and 15HQ-POSS/5CuTi) could prevent Pseudomonas PS27 biofilm formation at a certain concentration (250 μg mL−1) which greatly impaired bacterial planktonic growth. Specifically, 15HQ-POSS/5CuTi completely impaired cell adhesion, thus successfully prejudicing biofilm formation and proving its suitability as a potential antifouling agent. Considering that most studies deal with quaternary ammonium salts (QASs) with long alkyl chains (>10 carbon atoms), the results reported here on hexylimidazolium-based POSS further deepen the knowledge of QAS formulations which can be used as antifouling compounds.

Fluorosilicone rubber (F-LSR) is a promising material that can be applied in various cutting-edge industries. However, the slightly lower thermal resistance of F-LSR compared with that of conventional PDMS is difficult to overcome by applying nonreactive conventional fillers that readily agglomerate owing to their incompatible structure. Polyhedral oligomeric silsesquioxane with vinyl groups (POSS-V) is a suitable material that may satisfy this requirement. Herein, F-LSR-POSS was prepared using POSS-V as a chemical crosslinking agent chemically bonded with F-LSR through hydrosilylation. All F-LSR-POSSs were successfully prepared and most of the POSS-Vs were uniformly dispersed in the F-LSR-POSSs, as confirmed by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) measurements. The mechanical strength and crosslinking density of the F-LSR-POSSs were determined using a universal testing machine (UTM) and dynamic mechanical analysis (DMA), respectively. Finally, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements confirmed that the low-temperature thermal properties were maintained, and the heat resistance was significantly improved compared with conventional F-LSR. Eventually, the poor heat resistance of the F-LSR was overcome with three-dimensional high-density crosslinking by introducing POSS-V as a chemical crosslinking agent, thereby expanding the potential fluorosilicone applications.