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There is currently limited research on the structure-property relationship of reduction stimuli-responsive polymeric crosslinked micelles using mesoscopic simulations. Herein, dissipative particle dynamics (DPD) simulations were used to simulate the self-assembly process of the blank non-crosslinked micelle, the structure and doxorubicin (DOX) distribution of diselenide crosslinked micelle with different crosslinker contents (CCs) based on the nearest-neighbor bonding principle. The results revealed that the formation of a three-layer spherical micelle and the loaded DOX mainly distributed in the polycaprolactone (PCL) core and hydroxyethyl methacrylate (HEMA) mesosphere. The larger the dosage of DOX, the more DOX encapsulated, but the encapsulation of DOX in the hydrophobic domain would reach saturation when the dosage increased to 6.0 %. In micelles with lower CCs or crosslinking levels (CLs), DOX entered the middle layer and the inner core faster. Then, based on the nearest media-bead bond breaking principle and subsequently DPD simulation, the effects of different CCs on the micelle structure and DOX release properties were investigated. Low CC could cause fast drug release. With the increase of CCs, the micelle showed a slower DOX release trend. The multilayer crosslinked network system also affected the DOX release rate. Hence, this work can provide some mesoscale guidance for the structural design and structure-property relationship of stimuli-responsive reversible crosslinked micelles for drug delivery.

Developing a shape memory polyurethane with high mechanical properties, excellent self-healing has become a huge challenge for the development of smart materials. Herein, we report the design and fabrication of a shape memory polyurethane network terminated with coumarin units (HEOMC-PU) to address this conundrum. The synthesized HEOMC-PU exhibits exceptional mechanical performance with a breaking elongation of 746% and toughness of 55.5 MJ·m

A novel hybrid hydrogel system composed of CdTe QDs and SiO2 PCs was developed for optical anti-counterfeiting and information encoding–decoding.

In this work, Au nanoparticle (AuNP) arrays on shape memory polyurethane (SMPU) substrates serve as flexible materials for tunable localized surface plasmon resonance (LSPR). AuNP arrays prepared by diblock copolymer self-assembly are transferred from rigid silicon wafers onto flexible SMPU substrates with ultrasonic treatment rather than peeling off directly. The resultant AuNP array SMPU films have excellent mechanical properties and stable thermodynamic properties. The LSPR arising from AuNP arrays is increased by negative bending on SMPU substrates, whereas the LSPR is decreased by positive bending. Besides, upon uniaxial tension, the vertical LSPR is increased first then decreased, whereas the parallel LSPR is similar, resulting in the overall LSPR of AuNP arrays being increased first and then decreased with the mechanical uniaxial tension of SMPU. Moreover, the resultant AuNP array SMPU films exhibit excellent flexibility, stability, and homogeneity in practical surface-enhanced Raman scattering (SERS) application. This approach of incorporating AuNP arrays on SMPU substrates for tuning plasmonic properties have great potential applications in SERS, fluorescence enhancement, and newly optoelectronic materials.

A hyperbranched polyester with carboxyl end group (HPC) was synthesized by using trimellitic anhydride and neopentyl glycol as raw materials via A2 + B3 polycondensation. Then, waterborne hyperbranched polyester acrylate (WHPC) was synthesized by partially modifying the carboxylic groups of HPC with glycidyl methacrylate. In order to explore the influence of molecular weight, acrylate groups content, and ion groups content on performances, a series of WHPC films with different molecular weight, acrylate groups content, and ion groups content were prepared. The dynamic light scattering spectrometer analysis shows that the higher ionic groups content and the lower molecular weight cause the smaller particle size. The ionic group content has a positive effect on the solubility. The smaller molecular weight and particle size cause the lower viscosity. The Fourier-transform IR spectrophotometer reveals that the double bond final conversion increased with increasing acrylate groups content. The final conversion is between 69 and 86%. The curing speed is fast, and the curing time is about 70 s due to the numerous end groups owned by the hyperbranched structure. The dynamic mechanical thermal analysis coupled with end-use mechanical property tests illustrates that the crosslink density has a positive effect on the storage modulus and a negative effect on the flexibility. It is also found that glass transition temperature and pencil hardness are determined by the balance between crosslink segment and hyperbranched polyester segment. The thermogravimetric analysis proves that increased crosslink density and molecular weight promote the heat resistance of films. This work utilizes a novel hyperbranched structure that excels in viscosity, flexibility, and water solubility. Furthermore, the preparation process is convenient.

Developing high-performance perovskite solar cells (PSCs) with all of the functional layers fabricated at low temperature (

The four-arm star copolymers poly(methacrylic acid)-poly(2-hydroxyethyl methacrylate-disulfide~)-poly(poly(ethylene glycol) methyl ether methacrylate) (4AS-PMAAx-(PHEMA-SS~)y-PPEGMAz) with four different block ratios were synthesized and could self-assembled into cross-linked polymer micelles for the exploration of the structure-property relationship. The cross-linked polymer micelles in aqueous solution had low critical micelle concentration (CMC) values (1.9-4.6 mg/L), which exhibited better stability than non-cross-linked micelles. The CMC value decreased with the increase of the length of inner PMAA core and hydrophobic PHEMA cross-linked middle layer. The blank and doxorubicin (DOX)-loaded micelles with different block ratios were prepared by dialysis with the particle sizes of 120-240 nm. The longer inner PMAA core and cross-linked middle layer enhanced the drug loading content (DLC) results and led to relatively bigger particle sizes of polymer micelles. The in vitro DOX release data revealed that DOX-loaded micelles had low DOX cumulative release percentages of 18-37% after 110 h at pH 7.4, but up to 83-90% when introducing reductant GSH at pH 5.0. The 4AS-PMAA21.2-(PHEMASS≈)13.1-PPEGMA5.1 micelles with the longest PMAA core had the largest cumulative release of 90.1%. The DOX release process and mechanism of the micelles at different conditions fitted well with the semi-empirical equation. Overall, the results demonstrated that the block ratios and pH/redox-responsiveness of these four-arm star copolymers could be well-controlled and their self-assembled cross-linked micelles as anticancer drug carrier system could be improved by optimizing the different ratios.

Shape memory polymeric actuators containing interfacial self-assembled silver nanowires (AgNWs) were fabricated. The morphology and electrothermal effect of the aligned AgNWs were investigated. Voltages as low as less than 2 V enabled rapid shape recovery, in which the speeds as well as nonlinearity of the shape memory-based actuation were comparatively studied. Two distinct actuation stages and the underlying mechanism were disclosed. The findings may greatly benefit the application of self assembly of nano building blocks in flexible electronics and soft robot fields.

Inspired by the formation of random sparkling microcrystallines in naturally precious opals, we develop a new strategy to produce a class of unclonable photonic crystal hydrogels (UPCHs) induced by the electrostatic interaction effect, which further achieve unclonable encoding/decoding and random high-encrypted patterns along with an ultrahigh and controllable encoding capacity up to ca. 2 × 10

A new substrate, aligned Ag nanowires decorated with silver nanoparticle composite structure (AgNWs@AgNPs), was fabricated to investigate metal-enhanced fluorescence (MEF) and its mechanism. The new composite structure was fabricated via a three-phase interface assembly method followed by SnCl2 sensitization and AgNO3 reduction process. The size and distribution of the nanoparticles on silver nanowires increased with the sensitization and reduction cycles. The formation of AgNPs on the surfaces of AgNWs was confirmed by multiple characterization methods including scanning electron microscopy (SEM), transmission electron microscope (TEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that the fluorescence intensity of the poly(3-hexylthiophene) (P3HT) on the composite structure was greatly enhanced compared with that on bare glass substrate, and the intensity increased with the increase in particle sizes and density. The mechanism was based on the increase in excitation rate and the radiation decay rate. The new type of substrate could serve as a good and efficient MEF substrate for high-performance fluorescence-based devices.

Herein, benefiting from effective energy-dissipation mechanism, the high-performance thermoplastic elastomers (ZASM/SEBS composites) with excellent mechanical strength-toughness combination were prepared by blending 3-Amino-1,2,4-triazole (ATA), maleic anhydride grafted styrene-ethylene/butadiene-styrene triblock copolymer (SEBS-g-MA), zinc acetate and styrene-ethylene/butadiene-styrene triblock copolymer (SEBS) successively. The Zn2+-carboxyl coordination and hydrogen bonding dual-dynamic network of composites was proved by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The mechanical performance of ZASM/SEBS composites was investigated by tensile test. With the decreasing mass ratio of ZASM in ZASM/SEBS composites, the tensile strength and elongation at break increased firstly and then decreased. When the mass ratio of ZASM in composites was 30%, the tensile strength reached 32.1 MPa along with the elongation at break of 1383%, attaining the best mechanical strength-toughness combination. It is demonstrated that the ZASM/SEBS composites could be a promising substitute for traditional vulcanized rubber.

Novel approach has been constructed for preparing the amphiphilic star copolymer pH/reduction stimuli-responsive cross-linked micelles (SCMs) as a smart drug delivery system for the well-controlled anti-tumor drug doxorubicin (DOX) release. The SCMs had a low CMC value of 5.3 mg/L. The blank and DOX-loaded SCMs both had a spherical shape with sizes around 100&ndash, 180 nm. In addition, the good stability and well pH/reduction-sensitivity of the SCMs were determined by dynamic light scattering (DLS) as well. The SCMs owned a low release of DOX in bloodstream and normal tissues while it had a fast release in tumor higher glutathione (GSH) concentration and/or lower pH value conditions, which demonstrates their pH/reduction dual-responsiveness. Furthermore, we conducted the thermodynamic analysis to study the interactions between the DOX and polymer micelles in the DOX release process. The values of the thermodynamic parameters at pH 7.4 and at pH 5.0 conditions indicated that the DOX release was endothermic and controlled mainly by the forces of an electrostatic interaction. At pH 5.0 with 10 mM GSH condition, electrostatic interaction, chemical bond, and hydrophobic interactions contributed together on DOX release. With the low cytotoxicity of blank SCMs and well cytotoxicity of DOX-loaded SCMs, the results indicated that the SCMs could form a smart cancer microenvironment-responsive drug delivery system. The release kinetic and thermodynamic analysis offer a theoretical foundation for the interaction between drug molecules and polymer matrices, which helps provide a roadmap for the oriented design and control of anti-cancer drug release for cancer therapy.

Here, a novel and low cost redox flow fuel cell that directly converts raw biomass to electricity at low temperature without utilizing any noble metal catalyst is reported. In this cell, Fe3+ ion, which has strong oxidizing power and is chemical stable, was directly utilized as an oxidant for biomass in anolyte. The reduced Fe2+ acted as charge carriers, transferring the electrons to the anode of the cell and being converted back to Fe3+ simultaneously. The degradation chemistry of the biomass from the oxidation reaction and the apparent oxidation kinetics were investigated using glucose as the biomass model compound. The results showed that glucose was decomposed to small organic molecules and even CO2, and the reaction rate was significantly affected by temperature and content of reactant. The apparent activation energy of the redox reaction is 127.85 kJ·mol−1 based on the linear relation equation at the initial stage of the reaction. And the preference conditions of the redox reaction are 100–110 °C, 0.2–0.5 mol·L−1 glucose and the mol ratio of C6H12O6/FeCl3 from 1:10 to 1:12. Meantime, a high potential (VO2)2SO4 solution was synthesized as catholyte which was regenerated by O2 in the present of small amount of HNO3. The power density and discharge current density of the biomass redox flow fuel cell could reach 125.7 mW·cm−2 and 314.2 mA·cm−2, respectively, which was about 755 times higher than the reported microbial fuel cell by utilizing glucose as substrate. This work provides a promising way for converting abundant natural biomasses, such as crop straws and bagasse, into electricity at low temperature (80–110 °C).

Although flexible conductive polymeric sensors responding to different stimulus have been extensively explored, it remains challenge to integrate high multi-stimuli sensitivity into one material. Herein, novel electromechanical sensors were fabricated, exhibiting dramatically enhanced strain- and water/moisture-sensitivity. The hybridized nano carbons of graphene and carbon nanotubes (CNTs) were regulated with cellulose nanocrystals (CNCs), followed by embedding into the polymeric elastomer via transfer process. The CNCs not only fragmentized the electromechanical networks under external stress, but also amplified the swelling effect on the conductivity variation as exposed upon water/moisture due to the mechanical reinforcement and amphiphilic nature. Micro/nano cracks were generated on the conductive surface layer, enabling dramatic enhancement on the sensitivity and reversibility in the strain sensing. The gauge factor was up to 1129 within 20% of the strain, which was higher by 182 times compared to that of the control sample without the CNCs content. Moreover, the electromechanical sensors improved the water/moisture sensing whose sensitivity was enhanced by 65 times due to the micro/nano cracks in the fragmentized carbon architecture. The findings extend the application of natural cellulose to exploit multi-stimuli responsive electronics and provide a facial strategy to optimize the sensory performance, which may greatly benefit the developments of the flexible and wearable electronics.

A high-quality 2-inch-diameter Nd3+, Ce3+ co-doped Y3Al5O12 (YAG) crystal was successfully grown by the Czochralski (CZ) method. During crystal growth, a modified temperature field was applied to prevent defects in the crystal. The spectrum of the sample showed strong absorption peaks corresponding to Nd3+ and Ce3+ ions. The effect of Ce3+ codoping on the photoluminescence of Nd3+ was investigated in detail. Strong 1066 nm emission of Nd3+ 4F3/2–4I11/2 was observed upon the 5d excitation of Ce3+. The energy transfer from Ce3+ to Nd3+ consists of nonradiative and radiative components. Compared to Nd:YAG, the double-doped Nd,Ce:YAG crystal realizes better utilization of the pump energy and higher laser energy output. Moreover, the laser threshold value is also significantly reduced. These results imply that Ce3+ doped into the YAG crystal acts as a good sensitizing ion for Nd3+. Hence, this double-doped Nd,Ce:YAG crystal is expected to be of industrial significance for manufacturing high-energy, low-volume solid-state lasers.

In this study, the galvanic displacement reaction between silver and AuCl4− was carried out to synthesize a series of silver nanowire (Ag NW) @ gold nanoparticle (Au NP) hybrid nanowires. The influence of Ag NW @ Au NP hybrid nanowires on the fluorescence properties of the poly (3-hexylthiophene) (P3HT) was investigated. The particle sizes of Au NPs on the hybrid nanowires could be adjusted by varying the reaction time and the concentration of the HAuCl4 solution. Furthermore, steady-state fluorescence measurements showed that the fluorescence intensity of the P3HT films was higher on various Ag NW @ Au NP hybrid nanowires compared to that on a bare silicon substrate. This was due to the increase in the intensity of electromagnetic field by the localized surface plasmon resonances of Au NPs and surface plasmon polaritons of Ag NWs from the hybrid nanowires. The results were further confirmed by the Raman spectra of the P3HT films on different substrates.

In this study, Cu@Ag core–shell nanoparticles (NPs) with highly environmental stability were synthesized successfully by combining the NaBH4 reduction method with the transmetallation reaction, and the Cu@Ag nano-ink was prepared for direct writing flexible electronics. The structure, component, thermal stability and oxidation resistance of Cu NPs and Cu@Ag core–shell nanoparticles were characterized and discussed systematically. The results showed that Cu NPs could be obtained via the reduction of Cu2+ ions by using cetyltrimethylammonium bromide (CTAB) as a dispersing agent under an excess of sodium hydroxide (NaOH) and sodium borohydride (NaBH4) in aqueous solution. And the Cu@Ag core–shell nanoparticles with uniform Ag shell and Cu core can be fabricated with the transmetallation reaction that Ag+ ions were reduced by the copper atoms on the surface of Cu NPs at pH 7, and the Cu core were kept from oxidation from the Ag shell. Besides, Cu@Ag nano ink were fabricated by dispersing Cu@Ag core–shell nanoparticles in ethylene glycol, and Cu@Ag conductive pattern were directly drawn on ordinary photo paper using a roller pen filled with 30 wt% Cu@Ag nano ink. The electrical resistivity of the conductive Cu@Ag pattern obtained from the nano ink was as low as 13.8 μΩ cm−1 due to the continuous interconnections between the nanoparticles established when thermal sintered at 150 °C for 1 h under N2. When the conductive wires of a lamp were connected to the two ends of the written conductive line, the lamp was illuminated immediately. It demonstrated that the complicated Cu@Ag nano-ink pattern had very good conductivity and applicability. This work provides an effective approach to prepare Cu@Ag core–shell nano-ink for direct writing flexible electronics.

Electrically conductive polymer composites were exploited to response stimuli based on multi-shape memory effect. Silver nanowires (AgNWs) network was embedded into a shape memory polymer blend possessing two discrete melting transition temperatures. The composites exhibited sequential triple shape recovery behaviors under the heat stimulation. Electro-mechanical measurements disclosed that the conduction varied along with the shape changes. Particularly, the influence of the compositions and stretching percentages on the electric/shape recovery was disclosed. The underlying morphology and microstructure evolutions were investigated. It is unprecedented to achieve the different temperatures sensing by one conductive polymer composite. The findings may greatly benefit the intelligent polymers in the multi-functional flexible electronics.

Hybrid nano-carbons of the reduced graphene oxide (rGO) and carbon nanotubes (CNTs) were utilized to fabricate the electrically conductive polymeric composites which exhibited superior flexibility, conductivity and tunable sensitivity to water exposure. Besides the conduction, morphologies and microstructure of the nanocarbon networks, the static and dynamic wetting behaviors as well as the absorption properties of the hybrid nanocarbons and the polymer composites were investigated. The emphasis was put on the influence of the composition on the sensory properties. The synergistic rGO-CNTs were found to magnify the water sensing, which may attribute to the swelling effect on the CNTs entanglement segregated by the rGO sheets. The findings may greatly benefit the exploration of nanocarbons in the field of the flexible sensory materials.

In this study, a Schottky-type ultraviolet (UV) photodetector based on double-layered nanostructured TiO 2 /Au films was fabricated. Double-layered titanium dioxide (TiO 2 ) nanostructures composed of one layer of TiO 2 nano-flowers on one layer of TiO 2 nanorods on fluorine-doped tin oxide (FTO) pre-coated glass substrates were synthesized via a convenient hydrothermal method using titanium butoxide and hydrochloric acid as the starting precursor, without involving the use of any other surfactants and catalysts. A granular-shaped thin-layer of Au film using vacuum sputter coating technique was subsequently deposited on TiO 2 for the formation of Schottky-type photodetector. The as-fabricated Schottky device showed various photocurrent responses when irradiated with different wavelength of UV light. This suggests that the newly-developed photodetectors have promising potential for identifying different UV light wavelengths.

A novel gap-plasmon of Fe3O4@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B (RB) was developed. Fe3O4@Ag core-shell nanostructures with Ag shell and Fe3O4 core were synthetized by self-assembled method with the assistance of 3-mercaptopropyl trimethoxy silane (MPTS). To study the RB fluorescence enhanced by gap-plasmon, the fluorescence properties of RB on the substrates with different nanogap densities were systematically investigated, and the results showed that the fluorescence intensity of RB on Fe3O4@Ag core-shell NPs substrate was much stronger than that on bare glass substrate, and the fluorescence intensity was further improved by using multilayer Fe3O4@Ag core-shell NPs substrate which had higher nanogap density. Different from the mechanism that is based on the maximum overlap of the surface plasmon resonance (SPR) band and emission band, the mechanism of the fluorescence enhancement in our work is based on the localized surface plasmon (LSP) and the gap plasmon near-field coupling with the Fe3O4@Ag core-shell NPs. Besides, the detection limit obtained was as low as 1×10-7 mol/L, and the Fe3O4@Ag core-shell NPs substrate had high selectivity for RB fluorophores. It was demonstrated that the Fe3O4@Ag core-shell NPs substrate had activity, good stability, and selectivity for fluorescence detection of RB. And the detection of RB by the surface plasmon enhanced fluorescence was more convenient and rapid than the traditional detection methods in previous works.