A theoretical model for impact protection of flexible polymer material

The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is obtained.Based on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is obtained.The feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by formula.The model is discretized and the relationship between local impact response andmaterial parameters is analyzed.The discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.

Flexible polymeric patch based nanotherapeutics against non-cancer therapy

Flexible polymeric patches find widespread applications in biomedicine because of their biological and tunable features including excellent patient compliance,superior biocompatibility and biodegradation,as well as high loading capability and permeability of drug.Such polymeric patches are classified into microneedles(MNs),hydrogel,microcapsule,microsphere and fiber depending on the formed morphology.The combination of nanomaterials with polymeric patches allows for improved advantages of increased curative efficacy and lowered systemic toxicity,promoting on-demand and regulated drug administration,thus providing the great potential to their clinic translation.In this review,the category of flexible polymeric patches that are utilized to integrate with nanomaterials is briefly presented and their advantages in bioapplications are further discussed.The applications of nanomaterials embedded polymeric patches in non-cancerous diseases were also systematically reviewed,including diabetes therapy,wound healing,dermatological disease therapy,bone regeneration,cardiac repair,hair repair,obesity therapy and some immune disease therapy.Alternatively,the limitations,latest challenges and future perspectives of such biomedical therapeutic devices are addressed.

Copper nanowire-TiO2-polyacrylate composite electrodes with high conductivity and smoothness for flexible polymer solar cells

Copper nanowire （Cu NW） transparent electrodes have attracted considerable attention due to their outstanding electrical properties, flexibility and low cost. However, complicated post-treatment techniques are needed to obtain good electrical conductivity, because of the organic residues and oxide layers on the surface of the Cu NWs. In addition, commonly used methods such as thermal annealing and acid treatment often lead to nanowire damage. Herein, a TiO2 sol treatment was introduced to obtain Cu NW transparent electrodes with superb performance （13 Ω/sq @ 82% T） at room temperature within one minute. Polymer solar ceils with excellent flexibility were then fabricated on the copper nanowire- TiO2-polyacrylate composite electrode. The power conversion efficiency （PCE） of the cells based on a blend of poly（3-hexylthiophene） （P3HT） and phenyl-C61- butyric acid methyl ester （PC61BM） reached 3.11%, which was better than the control devices that used indium tin oxide （ITO）-PET electrodes, and outperforms other Cu NW based organic solar cells previously reported. The PCE of the solar cells based on Cu NW electrodes remained at 90% after 500 cycles of bending, while the PET/ITO solar cells failed after 20 and 200 cycles, with sheet resistance of 35 and 15 Ω/sq, respectively.

Incorporation of flexible ionic polymers into a Lewis acid-functionalized mesoporous silica for cooperative conversion of CO2 to cyclic carbonates

A rational integration of multiple reactive centers into a combined unit to facilitate their cooperative effects is a smart approach for accelerating the catalytic activity.Here,to achieve this goal,linear imidazolium-based ionic polymers were confined into the nanopores of mesoporous silica nanospheres anchored with homogeneously distributed zinc salts.Owing to the flexible character and the reinforced cooperative effects of the ionic liquid(nucleophile)and zinc species(Lewis acid)in the confined mesoporous structure,the resultant composite exhibited dramatically improved catalytic performance in the cycloaddition of CO2 with epoxides to form cyclic carbonates.This was in contrast to that observed for the individual catalytic components.Moreover,such a solid catalyst could be easily recovered and reused four times without a significant loss of activity.

Syntheses,Structures,and Properties of Three New Polymers Based on Flexible and Rigid Ligands

Three new supramolecular polymers, [（IP）（H2SO4）（H2O）]（1）, [（H2SDC）（BPA）]（2） and [Mn（SDC）（IP）2]n （3）, have been constructed by three modes（rigid IP, rigid SDC ＋ flexible BPA, rigid IP ＋ rigid SDC）. Polymers 1 and 2 are supramolecular structures, assembled by hydrogen bonds and π···π interactions. X-ray structure analysis of 3 shows waved 1D chains which form a 3D supramolecular network by hydrogen bonds and π···π interactions. Solid-state properties of thermal stability, luminescent properties, and X-ray powder diffractions for these crystalline materials have also been investigated, and polymer 3 is considered to be a good stable luminescence material.

Syntheses,Structures and Properties of Two New Coordination Polymers with Flexible Ligands as Linkers

Two new coordination polymers,[ZnL1]n（1,H2L1 = 5-（4-pyridyl）-methoxyl isophthalic acid） and[Ni（L2）2（H2O）4]n（2,HL2 = 4-（pyridin-4-ylmethoxy）benzolic acid）,have been synthesized and characterized by elemental analysis,PXRD,IR spectra,and single-crystal X-ray diffraction.Compound 1 has a three-dimensional framework constructed by 6-bridged L1^2- anions connecting the Zn2（O2C）4 paddlewheel-like units.Compound 2 contains a mononuclear molecular unit,and the central nickel atom adopts a slightly distorted octahedral geometry by two nitrogen atoms from different L2^- ligands and four oxygen atoms from water molecules.These molecular units link each other via four types of O-H…O hydrogen bonds to form an extended three-dimensional（3D） supramolecular network.The thermal and photoluminescent properties of 1 and 2 have also been investigated.

Flexible Polydimethylsiloxane Composite with Multi-Scale Conductive Network for Ultra-Strong Electromagnetic Interference Protection

Highly conductive polymer composites(CPCs) with excellent mechanical flexibility are ideal materials for designing excellent electromagnetic interference(EMI) shielding materials,which can be used for the electromagnetic interference protection of flexible electronic devices.It is extremely urgent to fabricate ultra-strong EMI shielding CPCs with efficient conductive networks.In this paper,a novel silver-plated polylactide short fiber(Ag@PL ASF,AAF) was fabricated and was integrated with carbon nanotubes(CNT) to construct a multi-scale conductive network in polydimethylsiloxane(PDMS) matrix.The multi-scale conductive network endowed the flexible PDMS/AAF/CNT composite with excellent electrical conductivity of 440 S m-1and ultra-strong EMI shielding effectiveness(EMI SE) of up to 113 dB,containing only 5.0 vol% of AAF and 3.0 vol% of CNT(11.1wt% conductive filler content).Due to its excellent flexibility,the composite still showed 94% and 90% retention rates of EMI SE even after subjected to a simulated aging strategy(60℃ for 7 days) and 10,000 bending-releasing cycles.This strategy provides an important guidance for designing excellent EMI shielding materials to protect the workspace,environment and sensitive circuits against radiation for flexible electronic devices.

Flexible conductive polymer composites for smart wearable strain sensors

Wearable strain sensors based on flexible conductive polymer composites(FCPCs)have attracted great attention due to their applications in the fields of human–machine interaction,disease diagnostics,human motion detection,and soft robotic skin.In recent decades,FCPC‐based strain sensors with high stretchability and sensitivity,short response time,and excellent stability have been developed,which are expected to be more versatile and intelligent.Smart strain sensors are required to provide wearable comfort,such as breathability,selfcooling ability,and so forth.To adapt to the harsh environment,wearable strain sensors should also be highly adaptive to protect the skin and the sensor itself.In addition,portable power supply system,multisite sensing capability,and multifunctionality are crucial for the next generation of FCPC‐based strain sensor.

Electrochemical performance of all-solid lithium ion batteries with a polyaniline film cathode

We have prepared a high-density polyaniline（PANI） paste（50 mg/m L）, with similar physical properties to those of paints or pigments. The synthesis of PANI is confirmed by Fourier transform infrared（FT-IR） spectroscopy. The morphologies of PANI, doped PANI, and doped PANI paste are confirmed by scanning electron microscopy（SEM）. Particles of doped PANI paste are approximately 40–50 nm in diameter, with a uniform and cubic shape. The electrochemical performances of doped PANI paste using both liquid and solid polymer electrolytes have been measured by galvanostatic charge and discharge process. The cell fabricated with doped PANI paste and the solid polymer electrolyte exhibits a discharge capacity of ～87 μAh/cm2（64.0 m Ah/g） at the second cycle and～67 μAh/cm2（50.1 m Ah/g） at the 100 th cycle.