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Design of high energy density lithium storage materials is one of the everlasting issues in energy storage systems to realize a fully clean and sustainable energy grid. Here, 2,9-dimethyl quinacridone was selected as a precursor to prepare carbon-based electrode via low temperature heat-treatment process from 750 °C to 1050 °C. The pyro-polymerization of 2,9-dimethyl quinacridone induced a distinctive morphological transformation from rice husk-shaped 2,9-dimethyl quinacridone to carbon nanofibers. Electrode fabricated from pigment derived carbon nanofibers (PCNF) pyrolyzed at 750 °C maintained 878 mAh g-1 at a current density of 1 A g-1 and good Coulombic efficiency up to 98% after 1000 cycles. Furthermore, it delivered 337 mAh g-1 at a high current density of 25 A g-1. The superior performance was attributed to the stable structure of pristine 2,9-dimethyl quinacridone giving high thermal stability and crystallinity owing to well-defined π-π and hydrogen bonding interactions, thus rendering a stable microstructure with a large d-spacing of (002) plane of 3.580 A, as well as efficient surface redox reactions. Density functional theory calculations indicated that the large interlayer distance could facilitate fast lithium ion insertion/extraction because of a ∼38% lower energy barrier for lithium ion insertion than compared with graphite.

Non-aqueous lithium-ion redox flow batteries (Li-RFBs) have recently garnered much interest because of their high operating voltage and energy density. Albeit these outstanding advantages, challenges, such as poor cyclability and efficiency, still remain in employing the practical application. In an attempt to address these problems, a series of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and TEMPO derivatives catholytes were prepared and investigated as redox-active materials. Electrochemical evaluation exhibited that the introduction of polar and electron-withdrawing substituents to TEMPO was able to enhance the rate capability and cycling stability, when compared to those with the neat TEMPO. Extensive analysis of the electrochemical properties revealed that the electrophilic heteroatom stabilized the radical as well as alleviated the catholyte degradation. Overall, a careful selection of redox-active species demonstrates great promise in improving the current redox flow battery technology.

Poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/Nylon 66 blends have been considered as the potential heat resistant engineering plastics with high mechanical toughness and flame retardancy, suitable for high temperature applications. However, incompatibility between PPE and Nylon 66 and poor thermal stability of Nylon 66 degrade mechanical toughness and flame retardancy. In this work, for the first time, the PPE/Nylon 66 blends with high mechanical toughness and flame retardancy simultaneously have been prepared through newly synthesized compatibilizer of PPE grafted with fumaric acid (PPE-g-FA) and environmental-friendly non-halogen organic phosphinate flame retardant. The PPE/Nylon 66 blend achieved not only V0 grade flame retardancy with the help of improved fire resistance through the solid phase reaction of non-halogenic flame retardant, but also large impact strength larger than 10 kJ/m2 due to the strong compatibility of PPE-g-FA.

Fuel cells operating at above 100 °C under anhydrous conditions provide an ideal solution for the heat rejection problem of heavy-duty vehicle applications. Here, we report protonated phosphonic acid electrodes that remarkably improve fuel cell performance. The protonated phosphonic acids are comprised of tetrafluorostyrene phosphonic acid and perfluorosulfonic acid polymers in which a proton of the perfluorosulfonic acid is transferred to the phosphonic acid to enhance the anhydrous proton conduction of fuel cell electrodes. By implementing this material into fuel cell electrodes, we obtained a fuel cell exhibiting a rated power density of 780 milliwatts per square centimeter at 160 °C, with minimal degradation during 2,500 hours of operation, and 700 thermal cycles from 40 to 160 °C under load.

Silica nanoparticles were chemically grafted onto a porous polyethylene separator to improve the adhesion strength, thermal stability, and electrochemical performance of a polyolefin separator. A surface activation via UVO plasma treatment, followed by silane hybridization yielded a polymeric binder-free, thin coating of SiO2 nanoparticles onto the separator. The chemical grafting provided a much stronger adhesive strength (> 2.5 N/cm), reduced thermal shrinkage (

Anode ionomers of alkaline membrane fuel cells (AMFCs) play a critical role in hydrogen and water transport thus affecting cell performance and durability. Here, we modified a quaternized poly(biphenyl alkylene) ionomer with two chemical structural variations to increase hydrogen access to the AMFC anode: first, we introduced the symmetric dimethyl groups in the polymer backbone to increase polymer fractional free volume. Second, we replaced hydroxide-conducting alkyl trimethylammonium with alkyl triethylammonium to reduce cation–hydroxide–water co-adsorption on the hydrogen oxidation catalyst to increase hydrogen access to the co-adsorbed layer. We compared the performance benefits of the two structural variations through operating AMFCs under H2/O2 conditions. The membrane electrode assembly employing the modified poly(biphenyl alkylene) ionomer at the anode exhibited >1500 mW cm−2 peak power density at 80 °C with stable short-term durability (>100 h) under a constant current density of 0.6 A cm−2. This study provides an essential insight into designing anode ionomer of highly performing AMFCs.

Carbon molecular sieve (CMS) membranes are a promising candidate for natural gas processing due to their peculiar pore structure-induced excellent separation performance. Formulating ultrathin, defect-free CMS hollow fiber membranes is, however, still challenging due to damage on porous sub-structures induced by thermal relaxation of polymer chains during pyrolysis. Herein, we report a new methodology enabling high separation performance and good plasticization resistance in CMS fiber membranes by uniform integration of double-stranded polysilsesquioxanes into the polyimide matrix. Our polyimide/ladder-structured polysilsesquioxane CMS fibers substantially enhanced CO2 permeance by as much as 546% compared to the precursor fiber analogues due to the thin molecular sieve selective layer. Also, poly(dimethylsiloxane) coating delayed physical aging, still showing a high CO2 permeance of 354 GPU with CO2/CH4 selectivity of 56 after 72 days of aging. Furthermore, they exhibited excellent plasticization resistance up to a CO2 partial pressure of 13.2 bar with CO2/CH4 separation factor of 74 for an equimolar CO2/CH4 feed mixture.

A series of UV-curable hybrid composite blends containing a carboxylic acid functionalized polyimidewith varying amounts of high molecular weight (~1 K) PEG-grafted ladder-structured polysilsesquioxanes copolymerized with methacryl groups were fabricated and their structural, thermal, mechanical, and surface properties characterized. At a composite weight ratio of polyimide above 50 wt.%, a stark shift from amorphous to crystalline polyethylene glycol (PEG) phases were observed, accompanied by a drastic increase in both surface moduli and brittleness index. Moreover, fabricated composites were shown to have a wide range water contact angle, 9.8&deg, &ndash, 73.8&deg, attesting to the tunable surface properties of these amphiphilic hybrid polymer composites. The enhanced mechanical properties, combined with the utility of tunable surface hydrophilicity allows for the possible use of these hybrid polymer composites to be utilized as photosensitive polyimide negative photoresists for a myriad of semiconductor patterning processes.

Modern electrochemical energy conversion devices require more advanced proton conductors for their broad applications. Phosphonated polymers have been proposed as anhydrous proton conductors for fuel cells. However, the anhydride formation of phosphonic acid functional groups lowers proton conductivity and this prevents the use of phosphonated polymers in fuel cell applications. Here, we report a poly(2,3,5,6-tetrafluorostyrene-4-phosphonic acid) that does not undergo anhydride formation and thus maintains protonic conductivity above 200 °C. We use the phosphonated polymer in fuel cell electrodes with an ion-pair coordinated membrane in a membrane electrode assembly. This synergistically integrated fuel cell reached peak power densities of 1,130 mW cm−2 at 160 °C and 1,740 mW cm−2 at 240 °C under H2/O2 conditions, substantially outperforming polybenzimidazole- and metal phosphate-based fuel cells. Our result indicates a pathway towards using phosphonated polymers in high-performance fuel cells under hot and dry operating conditions. Phosphonated polymers have been proposed as anhydrous proton conductors for fuel cells but anhydride formation of phosphonic acid functional groups lowers conductivity. A synergistically integrated phosphonated poly(pentafluorostyrene) is shown to maintain high protonic conductivity above 200 °C.

A series of ladder-like polysilsesquioxanes (LPSQs) containing the UV-curable methacryoxypropyl (MA) and different organic functional (R) groups (propyl, hexyl, cyclohexyl, phenyl or naphthyl) at the fixed MA/R molar ratio were synthesized as hard coating materials. The LPSQ hard coating films prepared by a simple UV curing process exhibited excellent optical transparency in the visible light range. X-ray diffraction analysis of the LPSQ films characterized how their intermolecular chain-to-chain distance and thus chain packing density varied according to the organic functional group. In addition, the hardness, elastic modulus and scratch resistance of the LPSQ films were evaluated by nanoindentation and nanoscratch tests. Although the mechanical properties of the LPSQ films were affected by both the chain rigidity of the organic functional group and the chain packing density of the siloxane backbones, chain rigidity played the dominant role in determining their mechanical robustness. Hence, despite its lowest chain packing density, the LPSQ film with the naphthyl group exhibited the best mechanical properties due to its high chain rigidity derived from the increased aromaticity of the naphthyl group. This study suggests the key factor when designing mechanically durable, scratch resistant hard coating films is the chain rigidity of the film network.

An effective method to enhance the durability of polymer electrolyte membrane fuel cells (PEMFCs) is reported. PEMFC performance loss is mitigated by exposing the electrodes of fuel cells to dry nitrogen gas periodically at high temperature. This method extends the lifetime of fuel cells significantly compared to their non-treated counterparts. The impact of treatment temperature and exposure time on PEMFC durability is reported, using potential cycling accelerated stress tests. The enhanced durability is attributed to the suppression of “ionomer relaxation” that occurs under the nearly water saturated operating conditions of a PEMFC cathode.

This paper reports the recycling of flexible printed circuit board (FPCB) waste through carbonization of polyimide by dual pyrolysis processes. The organic matter was recovered as pyrolyzed oil at low temperatures, while valuable metals and polyimide-derived carbon were effectively recovered through secondary high temperature pyrolysis. The major component of organics extracted from FPCB waste comprised of epoxy resins were identified as pyrolysis oils containing bisphenol-A. The valuable metals (Cu, Ni, Ag, Sn, Au, Pd) in waste FPCB were recovered as granular shape and quantitatively analyzed via ICP-OES. In attempt to produce carbonaceous material with increased degree of graphitization at low heat-treatment conditions, the catalytic effect of transition metals within FPCB waste was investigated for the efficient carbonization of polyimide films. The morphology of the carbon powder was observed by scanning electron microscopy and graphitic carbonization was investigated with X-ray analysis. The protocols outlined in this study may allow for propitious opportunities to salvage both organic and inorganic materials from FPCB waste products for a sustainable future.

Pourable and room temperature flowable ladder-structured polysilsesquioxanes were synthesized and applied as functional optical hard coatings. Organic functional group type (propyl, hexyl, octyl, dodecyl) and their copolymer composition with UV-curable methylacryloxypropyl group were selected as to control both pre-cured viscosity and final mechanical properties independent of molecular weight. Ladder-structured polysilsesquioxanes with longer alkyl side chains exhibited higher fluidity and flexibility while maintaining its optical property and mechanical strength. The solvent-free processability of our synthesized materials along with their superior optical and mechanical properties over commercial solvent-based hard coatings suggest the high value of our hybrid materials for the coatings industry.

To data, combination of Pt-based bimetallic nanocrysatals and the graphene support have significantly contributed to enhance the oxygen reduction reaction (ORR) performance relative to electrocatalysts based on monometallic Pt nanoparticles (NPs) primarily due to the unique ligand effects and benefits of the carbon support. In this study, we propose a new structure of bimetallic electrocatalysts to realize the synergistic effects on the ORR performance through effective integration of the fine-sized Pt NPs, PdPt bimetallic nanocrystals, and non-covalently functionalized graphene with ionic polymers. The facile wet-chemical methods were applied to synthesize fine-sized (2–5 nm) spherical Pt NPs doped large-sized (20–50 nm) non-spherical PdPt bimetallic NPs on the electronically negative ionic polymer-functionalized graphene support (Pt-on-PdPt/fG). This Pt-on-PdPt/fG with synergistic effects based on enlarged active surface area, ligand, and interfacial linking effects, exhibits substantially enhanced ORR activity (specific activity: 1.89 mA c m Pt − 2 at 0.9 VRHE) and durability in comparison to the commercial Pt/C (specific activity: 0.23 mA c m Pt − 2 at 0.9 VRHE). To this end, the effective integration of newly designed fine-sized Pt NPs doped bimetallic nanocrystals and unique graphene supports with the well-interactive ability could be a good platform to develop the advanced electrocatalysts for the efficient ORR.

Thermally curable hybrid ionogel electrolytes consisting of epoxy-functionalized POSS, amine-terminated polypropylene glycol, and ionic liquid electrolyte, 1 M LiTFSI in BMPTFSI were fabricated to give ionic conducting epoxy networks with cubic inorganic star networks crosslinked with lithium ion dissociating polypropylene glycol linkers. Characterization of these hybrid ionogels revealed high ion conduction, exceptional thermal stability, and electrochemical stability. Lithium ion capacitors fabricated with these hybrid ionogels revealed exceptional performance on par with the neat liquid ionic liquid electrolyte, and far superior over ionogels fabricated with conventional organic crosslinkers, due to the mechanical robustness and lithium ion dissociative character imparted by the POSS and PPG functionalities.

Developing polymeric membranes with propylene/propane separation performance surpassing the upper bound has been received much attention. Herein, a highly controlled thermal treatment process yielding microporous polyimide membranes made from dense brominated-polyimide membrane precursor via thermal debromination/cross-linking approach is demonstrated. We showed that facile thermal treatment could generate a narrow size distribution of micro-voids as well as covalent linkages between inter/intra polymer chains while the polyimide backbone structure remained intact. The thermally treated membranes were well-characterized by FTIR, TGA, WAXD, solid-state 13C NMR and N2 adsorption/desorption isotherm. Single gas propylene/propane (C3H6/C3H8) separation performance greatly improved in terms of both selectivity and permeability, surpassing the trade-off line while maintaining flexible membrane properties. A thermal cross-linking treatment at 380 °C for 5 h exhibited the best C3H6 permeability of 84.70 barrer and C3H6/C3H8 selectivity of 14.6 with high plasticization resistance.

In this study, a liquid state sulfur polymer (LSP) was employed as asphalt pavement materials. The LSP/epoxy asphalt (LSPA) was easily fabricated by mixing LSP and epoxy resin at room temperature. The workability of as-mixed LSP/epoxy mixture was explored by controlling the ratio of epoxy. The asphalt mixture with the epoxy content below 50 wt% exhibited reliable flowability above approximately 12.5 cm. The solidification of LSP was successfully accompanied by simultaneous curing of epoxy. For practical application of pavement on road, the Marshall stability, indirect tensile strength and wheel tracking test were performed. The Marshall stability and indirect tensile strength of the LSPA exhibited an approximate 2-fold increase compared to neat asphalt. Moreover, exceptional durability of the LSPA was achieved through the controllable crushed depth of the pavement under wheel passes of 25,000 cycles. For practical repairing test on the road, the LSPA was cast on a pothole prepared on asphalt road. Our as-cast asphalt materials were suitable to heal potholes with seamless interface and the hardening was accomplished within a very short time of 1 h. The hardened LSPA exhibited excellent adhesion strength of approximately 1.95 MPa, enabling the elimination of gaps arising from traffic cycles and climate variation.

A series of multi-crosslinkable, self-healing, ladder-structured polysilsesquioxane inorganic-organic hybrid materials were developed to enhance the mechanical properties through tandem UV-curing and Diels-Alder chemistry. The introduction of UV-curable acryl- or epoxy groups allowed for a higher degree of crosslink density while bringing the inorganic backbones closer together for highly efficient self-healing properties, all with a singular material as the ternary organic functional groups consisting of UV-curable function, diene, and dienophile were tethered to the well-defined inorganic backbone. Exceptional thermal stability (>400 °C), optical transparency (>95%), solution processability, as well as robust surface mechanical properties in both bulk (pencil hardness 6H) and nanoscale (elastic modulus > 9 GPa), properties which can be adroitly recovered through mild and rapid thermal treatment hold great promise for next generation hybrid smart coating materials for application in optoelectronic devices.

Most inorganic nucleating agents for poly(ethylene terephthalate) (PET) have limited nucleating ability due to poor compatibility with PET. Polyhedral oligomeric silsesquioxanes (POSS) is a type of cage-shaped organic/inorganic hybrid nanoparticles with three different particle sizes: octameric (T8), decameric (T10), and dodecameric (T12). POSS is considered as a promising nucleating agent for PET because the inorganic moieties contribute to high thermal stability and nucleation and the organic moieties can be tethered to PET chains. In contrast to T8 POSS, the nucleation ability of T12 POSS for PET has been poorly reported. In this study, our newly synthesized aminopropyl functionalized T12 POSS (A-POSS) is proposed as a potential nucleating agent for PET. The amine group of A-POSS is able to be chemically conjugated to PET chains, thereby giving a more homogeneous dispersion of T12 POSS in PET than non-functional T12 Phenyl POSS (N-POSS). Its PET composites gave a ∼1.2 fold higher crystallization temperature and ∼2.7 fold higher shear-induced crystallization rate over pristine PET. Such nucleating effects for PET is more effective than those of non-functional T12 POSS and the more widely studied T8 POSS. This strategy is potentially beneficial for the high-shear melt processes of PET such as spinning and film extrusion.

Heteroleptic ruthenium-complexed ladder-like structured polysilsesquioxane (LPSQ-Ru) was synthesized by post coordination reaction of bidentate ligand side chains in LPSQ with reactive Ru(II) complexes, which was well characterized by 1H and 29Si NMR, FT-IR, and spectroscopic techniques. The photophysical properties of LPSQ-Ru were examined by UV and PL analyses in both solution and solid states, comparing to analogous polymers of ruthenium-complexed polystyrene (PS-Ru). Obtained absorptions of LPSQ-Ru and PS-Ru were broadened ranging from 390-490 nm regardless of the states. However, LPSQ-Ru exhibited higher and shaper PL emission spectrum in comparison to that of PS-Ru, particularly in the solid state, because Ru-complexes in LPSQ were much effectively isolated, preventing their aggregations due to the rigid double strained siloxane backbone. This extinguished photophysical property in LPSQ-Ru kept after intensive thermal treatment at 250 °C for 90 min, which was not achieved in PS-Ru (~5-fold decrease). These differences originated from the backbone structures were also appeared in electrochemical properties in the solid states.

A multifunctional crosslinkable and ionic-group functionalized ladder-like polysilsesquioxane was synthesized and utilized for the fabrication of hybrid ionogels for lithium ion batteries. The ionic-group functionalized ladder-like polysilsesquioxane combined the synergistic effects of hybrid materials in improving the thermal stability of conventional battery electrolytes, whilst maintain facile solution processability and chemically crosslinkable function in ionic conducting ionic liquid electrolyte media. Fabricated iongel electrolytes exhibiting exceptional thermal stability, mechanical properties, high ionic conductivity, and electrochemical stability. Lithium ion batteries fabricated with the hybrid ionic ladder-like polysilsesquioxane ionogels exhibited initial discharge capacities on par with neat liquid electrolytes, good rate performance, as well as stable cyclability and excellent Coulombic efficiency.

A new methodology for fabrication of inorganic–organic hybrid ionogels and scaffolds is developed through facile cross-linking and solution extraction of a newly developed ionic polyhedral oligomeric silsesquioxane with inorganic core. Through design of various cationic tertiary amines, as well as cross-linkable functional groups on each arm of the inorganic core, high-performance ionogels are fabricated with excellent electrochemical stability and unique ion conduction behavior, giving superior lithium ion battery performance. Moreover, through solvent extraction of the liquid components, hybrid scaffolds with well-defined, interconnected mesopores are utilized as heterogeneous catalysts for the CO2-catalyzed cycloaddition of epoxides. Excellent catalytic performance, as well as highly efficient recyclability are observed when compared to other previous literature materials.

A series of trimethylsilyl-capped hybrid ladder-like polysilsesquioxane (LPSQ-TMS) derivatives were synthesized comprising an inorganic backbone functionalized with various organic side moieties and compositional ratios with application towards gate dielectrics or surface modifying materials. The surface energy (γ) and roughness (Rq) values of the LPSQ-TMS coated SiO2 dielectrics were considerably affected by the side moieties of the polymer series; methyl, n-propyl, phenyl (P), naphthyl (N), methacryloxypropyl (MA), and fluorooctyl moieties. The γ values varied from 17.0 to 42.0 mJ m−2, while the Rq values also ranged from 0.34 to 1.10 nm. On polymer-treated SiO2 dielectrics possessing smooth and semiconductor-compatible surface properties, pentacene developed terrace-like crystallites formed through layer-by-island growth modes, a stark contrast to the three-dimensionally grown crystal islands formed on rough or extremely hydrophobic surfaces, which led to unfavorable conduction pathways. Depending on the order of conjugation and interconnections between the pentacene domains, the average mobility (μFET) values of the resulting 50 nm thick pentacene organic field-effect transistors were varied by two orders of magnitude and reached 0.8 cm2 V−1 s−1, specifically, for both the P- and MA-substituted LPSQ-TMS treated SiO2 dielectrics (γ = 37.0 mJ m−2 and Rq = 0.40 nm). Moreover, we were able to demonstrate that a thermally cured 500 nm thick LPSQ-TMS layer on an Au gate-patterned flexible polyimide substrate could yield pentacene OFETs with μFET values as high as 0.60 cm2 V−1 s−1, comparable to that of the LPSQ-TMS treated SiO2 system. Also, the proper introduction of organic substituents to LPSQ improved the gate-bias stress stability for high performance OFETs.

Boron containing ionogels were fabricated through chemical crosslinking of boron allyloxide with polyethylene glycol dimethacrylate in an ionic liquid electrolyte solution to obtain mechanically robust gels. Because of the relatively small concentration of crosslinking agent required to fully solidify the ionic liquid electrolyte, good characters of high ionic conductivity, high thermal stability, and good electrochemical stability were observed. A spectroscopic investigation of the boronic ionogels revealed that the lithium mobility was noticeably enhanced compared with ionogels fabricated without the boronic crosslinker, leading to promising Li-ion battery performance at elevated temperatures.

The durability of alkaline anion exchange membrane (AEM) electrolyzers is a critical requirement for implementing this technology in cost-effective hydrogen production. Here, we report that the electrochemical oxidation of the adsorbed phenyl group (found in the ionomer) on oxygen evolution catalysts produces phenol, which may cause performance deterioration in AEM electrolyzers. In-line 1H NMR kinetic analyses of phenyl oxidation in a model organic cation electrolyte shows that catalyst type significantly impacts the phenyl oxidation rate at an oxygen evolution potential. Density functional theory calculations show that the phenyl adsorption is a critical factor determining the phenyl oxidation. This research provides a path for the development of more durable AEM electrolyzers with components that can minimize the adverse impact induced by the phenyl group oxidation, such as the development of novel ionomers with fewer phenyl moieties or catalysts with less phenyl-adsorbing character.

Membrane-based separation technology is attractive for upgrading small-scale natural gas due to the benefits of the pressure-driven process with a small footprint. Very few carbon molecular sieve (CMS) membranes with high N2/CH4 separation efficiency have been reported since the relationship between CMS structure and separation performance has not been fully elucidated. Here, we report the significance of controlling the effective pore size in our newly developed hybrid CMS matrix for enhanced N2/CH4 selectivity based on experimental characterizations and density functional theory (DFT) calculations. A new class of CMS membranes with an excellent N2/CH4 selectivity is demonstrated by pyrolysis of a homogeneous, hydrogen-bonded blend of BTDA-Durene:DABA (3:2) polyimide and ladder-structured poly(phenyl-co-3-(2-aminoethylamino)propyl)silsesquioxane (LPDA64). DFT calculations suggest that electron accumulation at SiOx phases of hybrid CMS membranes strongly hinders the diffusion of CH4 compared to N2 due to a larger electron overlap, resulting in a smaller effective pore size. Moreover, elevating the pyrolysis temperatures enhanced the N2/CH4 solubility selectivity due to the strong repulsive interaction between the newly formed ultramicropores with CH4. As a result, the hybrid CMS membranes showed an excellent single gas and N2/CH4/C2H6 (20/76/4) mixed gas N2/CH4 selectivity (28 and 16, respectively).

A photosensitive ladder-structured polysilsesquioxane was synthesized for the development of flexible copper clad laminates through electroless plating of Cu. The developed ladder-structured polysilsesquioxane with controlled structure enabled easy introduction of protected thiol and allyl functional group, which under acidic conditions, the thiol group becomes deprotected. This deprotected thiol group enables UV-initiated thiol-ene curing of the exposed regions, while the unexposed regions containing free thiol groups act as seed initiators for Cu electroless plating, and the corresponding negative pattern fabrication process also possible. Through this facile method, we were able to develop flexible copper clad laminates of tunable Cu interconnect width size of high electrical conductivity according to photomask pattern and the insulating dielectric surrounding layer exhibiting low dielectric constant and low loss behavior without any corrosive Cu etching steps.

A novel inorganic–organic hybrid crosslinker was prepared through synthesis of a fully condensed, high molecular weight ladder-like poly(methacryloxypropyl)silsesquioxane (LPMASQ) in one pot with a facile, base-catalysed system. The fully condensed LPMASQ revealed good thermal (∼380 °C) and electrochemical stability (∼5.0 V) due to the absence of uncondensed silanol groups. LPMASQ also revealed good solubility in various organic solvents and fully gelated 1 M LiPF6 in ethyl carbonate–diethyl carbonate (EC–DEC, 3/7, v/v) electrolyte solution through fast thermal and photocuring even at a very low concentration of 2 wt%. These observations were attributed to the polymeric nature of LPMASQ containing over one hundred methacryl moieties on the rigid double-stranded siloxane backbone. To the best of our knowledge, formation of a gel polymer electrolyte with 2 wt% gelator is the smallest gelation concentration that has ever been reported. This leads to high ionic conductivity (∼6.0 mS cm−1), excellent Coulombic efficiency and battery cell performance, comparable with those of the neat liquid electrolyte. The small crosslinker content, thermal and electrochemical stability, fast thermal and photocuring and facile processing of the LPMASQ based GPEs, as well as excellent Li battery cell performances strongly hold great promise for future industrial battery applications.

The incorporation of pyrene-functionalized poly(methyl methacrylate)-b-poly(dimethylaminoethyl methacrylate) (PMMA-b-PDMAEMA) ionic block copolymer-wrapped carbon nanotubes (PBCNTs) with graphene oxide (GO) allows compact decoration of metal nanoparticles (NP) for use as robust catalysts. This well-tailored concept of the PBCNT-GO functional carbon support provides various features, including a two-dimensional (2D) structure, dimensional stability, versatile solubility (from toluene to water), enhanced diffusion of reagents, and recyclability. Among the various compositions of GO and PBCNT, 50 wt% of the PBCNT additive-containing support (PBCGO55) showed great hybridization potential for Ag, Au, and Pd NPs. In particular, the hybridization of PBCGO55 with Pd NPs (Pd-PBCGO55) displayed superior morphological features with compact decoration of ultra-fine NPs (1–3 nm), larger surface area, higher density of edge and corner atoms, better dispersion stability, and lesser aggregation of the decorated Pd NPs in comparison with the other hybrid catalysts. In the catalytic reduction of 4-nitrophenol (4-NP), the Pd-PBCGO55 hybrid catalyst exhibited the best catalytic performance, resulting in highly enhanced reaction rate constant (k) of 9.73 min−1 and catalytic activity of 141.8 mol mol−1 min−1, exhibiting a 50-fold increased rate constant and 30-fold increased catalytic activity in comparison to Ag-GO without PBCNT (k = 0.19 min−1, catalytic activity = 4.58 mol mol−1 min−1).

Supercritical methanol is a popular fluid as a supercritical medium for decrosslinking reaction of crosslinked polyethylene. However, due to its toxicity, a safe alternative medium is much to be desired. In this work, various sub- and supercritical fluids with different polarity characters were investigated to find a safe alternative medium for continuous decrosslinking of silane-crosslinked polyethylene (S-XLPE). Like methanol, all examined fluids, including ethanol, propanol, and water, exhibited first-order reaction kinetics regarding the gel content in the continuous decrosslinking process. The reaction rate constant values were observed as 2.806, 2.569, 2.383, and 2.130 min −1 in supercritical methanol, supercritical ethanol, supercritical 2-propanol, and subcritical water at 380 °C, respectively. As a non-toxic fluid with reaction kinetics very comparable to that of methanol, ethanol was found to be the best alternative medium for the continuous decrosslinking reaction of S-XLPE.

For the first time, an inorganic-organic hybrid polymer binder was used for the coating of hybrid composites on separators to enhance thermal stability and to prevent formation of lithium dendrite in lithium metal batteries. The fabricated hybrid-composite-coated separators exhibited minimal thermal shrinkage compared with the previous composite separators (5% change in dimension), maintenance of porosity (Gurley number ∼400 s/100 cm(3)), and high ionic conductivity (0.82 mS/cm). Lithium metal battery cell examinations with our hybrid-composite-coated separators revealed excellent C-rate and cyclability performance due to the prevention of lithium dendrite growth on the lithium anode even after 200 cycles under 0.2-5C (charge-discharge) conditions. The mechanism for lithium dendrite prevention was attributed to exceptional nanoscale surface mechanical properties of the hybrid composite coating layer compared with the lithium metal anode, as the elastic modulus of the hybrid-composite-coated separator far exceeded those of both the lithium metal anode and the required threshold for lithium metal dendrite prevention.

We present a new polyethylene glycol-functionalized polysilsesquioxane, a ladder-like structured poly(poly(ethylene oxide)-co-methacryloxypropyl)silsesquioxane) (PEO-SQ) hybrid-type polymer gelator to fabricate hybrid ionogel electrolytes for lithium ion capacitors. The organic-inorganic hybrid polymer gelator contains not only an inorganic ladder-like polysilsesquioxane backbone for the thermal and electrochemical stability, but also dual organic pendant groups consisting of free-dangling PEO chains and unsaturated methacryloxypropyl groups for enhanced lithium ion dissociation and thermal curing function, respectively. The successful crosslinking of 1 M LiTFSI in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI) ionic liquid with only a small amount of PEO-SQ hybrid crosslinker (5 wt%) gave non-leaking ionogels with high thermal stability (⿼400 °C), large ionic conductivities, and excellent lithium ion capacitor C-rate performance and cyclability, comparable to those of neat ionic liquid electrolyte and superior over conventional organic ionogels fabricated with organic crosslinkers without PEO-moeities.

Compatible hybrid composites (PVLPMA) comprising of poly(vinylidene fluoride) (PVDF) and UV-curable ladder-like polysilsesquioxane (LPMASQ) were investigated for maximizing synergetic effects in various properties. The PVDF fluoropolymer was found to be well-incorporated with the LPMASQ inorganic filler because of good hydrogen-bonding, and the compatibility rigorously investigated by FT-IR, DSC, and WAXS studies. In addition, the crosslinkable function arising from the methacryl-group of the LPMASQ inorganic filler with the aid of the radical source was evaluated from the analysis of various properties. After UV-crosslinking, PVLPMA hybrid composites showcased enhanced mechanical properties such as elastic modulus, surface modulus, and surface hardness with accordance to the increasing the LPMASQ quantity. In addition, hydrophobicity was observed through the increase in the water contact angle up to 115°, a value much larger than that of neat PVDF and cured LPMASQ. Furthermore, the enhanced electrical stability of PVLPMA hybrid composites was obtained through examination of dielectric properties and breakdown strength in comparison to neat PVDF. These PVDF-LPMASQ organic-inorganic compatible hybrid composites with enhanced properties arising from the good compatibility and synergetic effects can be applicable in the various fields supplanting neat PVDF.

We present a capacitive humidity sensor with molecularly engineered polyimide (PI) sensing layer. Molecularly engineered PIs were successfully prepared by synthesizing polyamic acids (PAAs) through blending of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), pyromellitic dianhydride (PMDA), and 4,4-(hexafluoroisopropylidene) diphthalic anhydride (6-FDA) as monomer, followed by thermal imidization, respectively. The molecularly engineered PIs exhibited high thermal stability as well as controllable water uptake properties. Capacitive performances of the humidity sensor with PIs were efficiently increased via simple molecular blending.

Herein, we investigated the effect of thermo-oxidative crosslinking of siloxanes on the C3H6/C3H8 separation performance of carbon molecular sieve (CMS) membranes derived from polymer blends of a fluorine-containing polyimide and a ladder-structured polysilsesquioxane (PI/LPSQ). The PI/LPSQ precursors self-generated fluorinated gases, which possibly lead to the cleavage of double-stranded siloxanes during pyrolysis. At the same time, residual siloxanes underwent thermo-oxidative crosslinking, which resulted in densification into nonporous inorganic SiO2 phases. Such impermeable SiO2 phases adversely affected the gas diffusion, decreasing C3H6 permeability but contributed to the significant enhancement in the C3H6/C3H8 selectivity up to as much as 67, because of the substantially enhanced diffusivity selectivity. Density functional theory-based pore size distribution analysis exhibited that the narrower pores in the range of 5.0–5.5 A emerged for the PI/LPSQ (80/20 w/w) CMS, supporting the enhancement in C3H6/C3H8 selectivity. Also, PI/LPSQ (80/20 w/w) CMS fibers aged for 30 days showed C3H6 permeance of 2.9 GPU and a C3H6/C3H8 selectivity of 57. Furthermore, the techno-economic analysis verified the economic feasibility of the proposed membrane for the C3H6/C3H8 separation process. It reflected that higher C3H6 permeability plays a significant role in reducing the total cost of C3H6/C3H8 separation process as long as the C3H6/C3H8 selectivity is above 30, implying the significance of anti-aging in CMS hollow fiber membranes.

A series of thiol-ene UV-curable inorganic–organic hybrid polysilsesquioxanes of various phenyl:methacryloxypropyl and phenyl:mercaptopropyl copolymer compositions were synthesized in one-batch using a base-catalyzed system. These thermoplastic photocurable ladder-like structured materials were examined as scratch-resistant, hard-coating materials on both glass and PET substrates. The unique fully condensed structure of the hybrid polymers allowed for simplified processing and through variation of the organic functional group, films with high transparency, tunable refractive indices in the range of 1.467–1.546, pencil hardness values of 9H, and high nanoindentation modulus were obtained (7 GPa). These scratch-resistant polysilsesquioxanes may provide insight into the different organic functional group compositions which allow for optimal mechanical properties.

Polysilsesquioxanes (PSSQs) are composite materials consisting of inorganic framework and organic functional groups. Their inherent dual characteristics offer various applications including microelectronics, optics and biosciences. For the first time, free standing ladder-like PSSQ films were successfully prepared for gas separations, allowing practical applications in the membrane area. In order to fabricate a free-standing PSSQ film, a novel ladder-like poly(phenyl-co-glycidoxypropyl) silsesquioxanes with phenyl:glycidoxypropyl copolymer ratio of 6:4 (LPG64) were synthesized by a base-catalyzed sol–gel reaction. Moreover, the LPG64 films were thermally crosslinked with octa(aminophenyl)-T8-silsesquioxane (OAPS) with different concentrations of OAPS. Single gas (i.e. He, H2, CO2, O2, N2, and CH4) transport measurements were performed for the LPG64 as well as LPG64/OAPS composite membranes. The LPG64 membrane exhibited a relatively high CO2 permeability of 47.88 Barrer compared to other gases with CO2/N2 permselectivity of 30.5. The annealing effect on the transport results of the LPG64 membrane was negligible due to its rigid inorganic framework. Combination of our transport analysis and XRD characterization demonstrated that the addition of OAPS led to more dense chain packing, reducing permeability for all the gases tested in this work with increase in permselectivities. Especially, the LPG64/OAPS (80/20 wt/wt) membrane improved He/N2 and H2/N2 permselectivities by 98% and 80%, respectively, compared to those for neat LPG64 membranes.

We synthesized an ultra-fine Pd nanocatalyst supported by ionic block copolymer doped reduced graphene oxide (Pd-PIBrGO) for ultra-accelerated nanocatalysis. This hybrid catalyst exhibited exceptionally advanced catalytic performance for the reduction of methylene blue using miniscule quantities of Pd-PIBrGO due to facilitated diffusion of reagents, resulting in full reduction within a few seconds and showing a 280-fold increase of the rate constant over Pd-rGO without ionic block copolymers.

A series of PEO-functionalized, ladder-like structured polysilsesquioxane copolymers were synthesized and utilized for the fabrication of PEGylated hybrid ionogels through chemical crosslinking of the ionic liquid, 1 M LiTFSI in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide. Through systematic variance of the copolymer concentration of methacryloxypropyl- and PEG groups, we were able to demonstrate enhanced ionic conductivity and lithium ion dissociation as the PEO content increased. Through an in-depth spectroscopic investigation of the ion conduction behavior of these PEGylated hybrid ionogels and comparison with hybrid ionogels without PEG groups, we were able to demonstrate how the enhancement in lithium ion battery performance for PEGylated hybrid iongels could be achieved at identical crosslinker concentrations.

A series of organic–inorganic hybrid spin-on-glass polymethylsilsesquioxanes were synthesized utilizing a cyclic siloxane precursor, 1,3,5,7-tetramethyl-1,3,5,7-tetrahydroxyl cyclosiloxane (MT4-OH), copolymerized with methyltriethoxysilane (MTES) at various comonomer ratios. By selectively introducing this 2-D cyclic crosslinker, we were able to obtain spin-on-glass hybrimers with low dielectric constant (2.5–2.7), high nanoindentation modulus (5–10.5 GPa), with high thermal stability (>700 °C) without the use of porogens or additives. The use of the cyclic monomer MT4-OH greatly increased the mechanical properties, which allowed for impeccable reliability of a variety of patterns obtained through etching and chemical mechanical planarization processes, while maintaining optimal gap-filling properties. Due to the superior dielectric, mechanical, and integrated processing of these materials, these hybrids derived from MT4-OH may be utilized as next generation spin-on-glass low-dielectric constant materials.

Hybrid ionogels fabricated using 1 M LiTFSI in N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPTFSI) crosslinked with ladder-like structured poly(methacryloxypropyl)silsesquioxane (LPMASQ) were investigated as high temperature ionogel electrolytes for lithium ion batteries. In addition to the exceedingly low crosslinker concentration (∼2 wt%) required to completely solidify the ionic liquids, which provided high ionic conductivities comparable to the liquid state ionic liquid, these hybrid ionogels exhibited superior thermal stabilities (>400 °C). Rigorous lithium ion battery cells fabricated using these hybrid ionogels revealed excellent cell performance at various C-rates at a variety of temperatures, comparable with those of neat liquid electrolytes. Moreover, these hybrid ionogels exhibited excellent cycling performance during 50 cycles at 90 °C, sustaining over 98% coulombic efficiency. Highly advantageous properties of these hybrid ionogels, such as high ionic conductivity in the gel state, thermal stability, excellent C-rate performance, cyclability and non-flammability, offer opportunities for applications as high temperature electrolytes.

Poly(methyl)silsesquioxane-based spin-on-glass resins incorporating both a cyclic precursor, 1,3,5,7-tetramethyl 1,3,5,7-tetrahydroxyl cyclosiloxane, and incompletely condensed methyl-substituted POSS were synthesized and their thermal, mechanical, and electrical properties were investigated as a function of the POSS loading content. By introducing incompletely condensed methyl-substituted POSS compounds at the molecular level as sol–gel precursors, exceptional thermal stability (>700 °C), good mechanical properties (elastic modulus >4.0 GPa), and an ultra-low dielectric constant (k = 1.8) were obtained. In addition to providing a new route towards fully poly(methyl)silsesquioxane-based spin-on-glass resins with the above properties, the realization of the application of integration circuits was evaluated to show that the ultra low-k, mechanically robust spin-on-glass materials were able to withstand harsh wet chemical and dry etching, as well as chemical mechanical planarization (CMP) processing.

A ladder-like structured poly(mercaptopropyl)silsesquioxane (LPMPSQ) was synthesized in one-bath, under mildly basic conditions at room temperature. Obtained LPMPSQ was utilized as a macroinitiator for thiol-ene graft photopolymerization of various vinyl monomers to give hard, soft, hydrophobic, and hydrophilic graft copolymers with low PDI (

A series of azido-functionalized ladder-like structures was prepared by direct azidation of ladder-like structured poly(p-chloromethylphenyl)silsesquioxane (LPCMPSQ) and poly(chloropropyl)silsesquioxane (LPAPSQ) in excellent yields with perfect substitution of the chloro-compounds. The azido-functionalized silsesquioxanes obtained were then photocured without additional photoinitiator to give highly cross-linked thin films with an exceptionally high modulus (> 12 GPa). Furthermore, these materials were shown to be patterned through photolithography to give impeccable micropatterned microstructures.

Designing topographic clusters is of significant interest, yet it remains challenging as they often lack mobility or deformability. Here we exploit the huge volumetric expansion (up to 3000%) of a new type of building block, thermally expandable microbombs. They consist of a viscoelastic polymeric shell and a volatile gas core, which, within structural confinement, create micro-clusters via inverse jamming and topographical close-packing. Upon heating, microbombs anchored in rigid confinement underwent balloon-like blowing up, allowing for dense clusters via soft interplay between viscoelastic shells. Importantly, the confinement is unyielding against the internal pressure of the microbombs, thereby enabling self-assembled clusters, which can be coupled with topographic inscription to introduce structural hierarchy on the clusters. Our strategy provides densely packed yet ultralight clusters with a variety of complex shapes, cleavages, curvatures, and hierarchy. In turn, these clusters will enrich our ability to explore the assemblies of the ever-increasing range of microparticle systems., Self-assembled systems are normally composed of incompressible building blocks, which constrain their space filling efficiency. Yu et al. show programmable, densely packed clusters using thermally expandable soft microparticles, whereby the self-assembling process is realized via a jamming transition.

UV-curable polysilsesquioxane materials were used to incorporate moth-eye structures on photovoltaic (PV) protective glass. These patterns were formed using a hybrid nanoimprint lithography technique and annealed at 100 °C to evaporate the solvent (xylene). Compared to the bare, un-patterned PV protective glass, the PV protective glass patterned on both sides had superior optical properties. Transmittance of the PV protective glass patterned on both sides increased by up to 3.13% and reflectance decreased by up to 3.42%, and the transmittance was increased for all angles of incidence. Furthermore, the JSC of devices with the PV protective glass patterned on both sides increased by up to 3.15%. Finally, a monitoring system was set up to measure electricity generated by PV modules. The efficiency of the PV module with PV protective glass patterned on both sides was enhanced by up to 12.16% compared with that of the PV module with un-patterned PV protective glass.