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The combination of nitric oxide (NO) and siRNA is highly desirable for cancer therapy. Here, the furoxans-grafted PEI polymer (FDP) with caspase-3 responsive cleavable DEVD linker was synthesized, and used to bind siRNAs via electrostatic interaction and self-assembled into FDP/siRNA nanoplexes by hydrophobic force. After cellular uptake and lysosomal escape, the FDP/siRNA nanoplexes could achieve GSH-triggered NO release, and then increase the activity of caspase-3. The activated caspase-3 could specifically cleave the DEVD peptide sequence and enhance cell apoptosis. With the cleavage of DEVD peptide sequence, the disassembly of FDP/siRNA nanoplexes was further promoted, thereby resulting in increased siRNAs of ~40% were released at 48 h compared with the caspase-3 non-responsive FDnP/siRNA nanoplexes. By this way, cell apoptosis promotion and cell proliferation inhibition was achieved by siRNA-based downregulation of EGFR protein and the upregulated activity of caspase-3, followed by the enhanced cascade release of NO from FDP/siRNA nanoplexes. Furthermore, in vivo results demonstrated the improved anti-cancer efficiency of FDP/siEGFR nanoplexes without any detectable side effects. Therefore, it is believed that the caspase-3 responsive cleavable furoxans-grafted PEI polymers could provide a potential and efficient enhancement for cancer therapeutic efficiency by the co-delivery of nitric oxide and siRNA. The FDP/siRNA nanoplexes formed by the electrostatic interaction of furoxans-grafted PEI polymer (FDP) and siRNA could achieve the promoted release of NO and siRNA with the caspase-3 responsive cleavage of DEVD linker, and thereby exhibited the improved combination effects of NO and siEGFR on cancer therapy. [Display omitted] • The caspase-3 responsive furoxans-grafted PEI polymer (FDP) was used for improving the co-delivery of siRNA and nitric oxide. • The FDP/siRNA nanoplexes achieved the promoted release of NO and siRNA with the caspase-3 responsive cleavage of DEVD linker. • The FDP/siEGFR nanoplexes exhibited the improved combination biological effects of NO and siEGFR on cancer therapy. [ABSTRACT FROM AUTHOR]

Interfaces between donor and acceptor semiconducting polymers are critical to the performance of polymer light-emitting diodes and organic solar cells. Similarly, interfaces between a conjugated polymer and a dielectric play a critical role in organic thin-film transistors. Often, these interfaces are difficult to characterize with conventional methods. Resonant soft x-ray reflectivity (R-SoXR) is a unique and relatively simple method to investigate such interfaces. R-SoXR capabilities are exemplified by presenting or discussing results from systems spanning all three device categories. We also demonstrate that the interfacial widths between active layers can be controlled by annealing at elevated temperature, pre-annealing of the bottom layer, or casting from different solvent mixtures. The extension of R-SoXR to the fluorine K absorption edge near 698 eV is also demonstrated. [ABSTRACT FROM AUTHOR]

Rather than a comprehensive review, the aim here is to provide a selection of examples showcasing the applications of synchrotron radiation in polymer and soft materials research, as well as highlighting a range of unique capabilities of each facility. This special issue will feature polymer and soft material research from a small selection of synchrotron facilities across the globe. Polymers and soft materials have a wide range of applications in different fields, including industrial, pharmaceutical, energy, and electronics. [Extracted from the article]

Two new donor (D)-acceptor (A) copolymers, poly({4,4′-[4,4′-(9 H-fluorene-9,9-diyl)bis(4,1-phenylene)]bis(oxy)diphthalonitrile}- alt-[dithieno [3,2- b:2′,3′- d]pyrrole]) (P1) and poly({4,4′-[4,4′-(9 H-fluorene-9,9-diyl)bis(4,1-phenylene)]bis(oxy)diphthalonitrile}- alt-([1,2- b:4,5-b′]dithiophene)) (P2), have been designed and synthesized by the Stille coupling reaction. The dipole moment of P1 (10.71 Debye) is larger than that of P2 (6.59 Debye). A strong dipole moment helps to sustain the conductive charge-transfer state. To evaluate the nonvolatile memristive performance of P1 and P2, the corresponding memory device can be fabricated with the configuration of platinum (50 nm)/polymer (100 nm)/platinum (150 nm)/silicon. In contrast with the P2-based device with almost negligible switching and memristive behavior, the P1-based memristor exhibits a maximum ILRS/ IHRS ratio of about 10 ( ILRS and IHRS are the current values in the low-resistance state (LRS) and high-resistance state (HRS), respectively) at ±2.0 V. Distinguishable from the bistable resistive switching, showing abrupt resistance or conductance jumps, the electrical transition observed in the memristor demonstrates a smoother tuning of the sample conductance during the voltage sweeping processes. In addition, changes in the surface morphology of P1 and P2 are also observed under an applied bias voltage of 100 mV. [ABSTRACT FROM AUTHOR]

Conjugated polymers (CPs) with low crystallinity are promising candidates for application in organic thermoelectrics (OTEs), particularly in flexible devices, because the disordered structures of these CPs can effectively accommodate dopants and ensure robust resistance to bending. However, n‐doped CPs usually exhibit poor thermoelectric performance, which hinders the development of high‐performance thermoelectric generators. Herein, we report an n‐type CP (ThDPP‐CNBTz) comprising two acceptor units: a thiophene‐flanked diketopyrrolopyrrole and a cyano‐functionalized benzothiadiazole. ThDPP‐CNBTz shows a low LUMO energy level of below −4.20 eV and features low crystallinity, enabling high doping efficiency. Moreover, the dual‐acceptor design enhances polaron delocalization, resulting in good thermoelectric performance. After n‐doping, ThDPP‐CNBTz exhibits an average electrical conductivity (σ) of 50.6 S cm−1 and a maximum power factor (PF) of 126.8 μW m−1 K−2, which is among the highest values reported for solution‐processed n‐type CPs to date. Additionally, a solution‐processed flexible OTE device based on doped ThDPP‐CNBTz exhibits a maximum PF of 70 μW m−1 K−2; the flexible device also shows remarkable resistance to bending strain, with only a marginal change in σ after 600 bending cycles. The findings presented in this work will advance the development of n‐type CPs for OTE devices, and flexible devices in particular. [ABSTRACT FROM AUTHOR]

Conjugated polymers (CPs) with low crystallinity are promising candidates for application in organic thermoelectrics (OTEs), particularly in flexible devices, because the disordered structures of these CPs can effectively accommodate dopants and ensure robust resistance to bending. However, n‐doped CPs usually exhibit poor thermoelectric performance, which hinders the development of high‐performance thermoelectric generators. Herein, we report an n‐type CP (ThDPP‐CNBTz) comprising two acceptor units: a thiophene‐flanked diketopyrrolopyrrole and a cyano‐functionalized benzothiadiazole. ThDPP‐CNBTz shows a low LUMO energy level of below −4.20 eV and features low crystallinity, enabling high doping efficiency. Moreover, the dual‐acceptor design enhances polaron delocalization, resulting in good thermoelectric performance. After n‐doping, ThDPP‐CNBTz exhibits an average electrical conductivity (σ) of 50.6 S cm−1 and a maximum power factor (PF) of 126.8 μW m−1 K−2, which is among the highest values reported for solution‐processed n‐type CPs to date. Additionally, a solution‐processed flexible OTE device based on doped ThDPP‐CNBTz exhibits a maximum PF of 70 μW m−1 K−2; the flexible device also shows remarkable resistance to bending strain, with only a marginal change in σ after 600 bending cycles. The findings presented in this work will advance the development of n‐type CPs for OTE devices, and flexible devices in particular. [ABSTRACT FROM AUTHOR]

L-glutamic acid (LA) is a bio-based, non-toxic, environmentally friendly material derived from biomass. The present study reports the application of Passerini three-component polymerization (P-3CP) for the straightforward preparation of LA-based light-responsive polyesters (PLTDs) under mild conditions. PLTDs with molar masses up to 8500 g/mol and high yields exceeding 90% are obtained. The chemical structures and light-responsive self-immolative behavior of PLTDs are comprehensively characterized by employing ultraviolet-visible (UV-Vis) spectroscopy, size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy, and liquid chromatography mass spectrometry (LC-MS). Meanwhile, monodisperse PLTD-based doxorubicin-loaded nanoparticles (PLTD-DOX-NP) (size=193 nm, PDI=0.018) are formulated by nanoprecipitation method. Upon light-induced depolymerization, the PLTD-DOX-NP undergoes rapid decomposition, resulting in a burst release of 80% cargo within 13 s. Furthermore, according to biological toxicity tests, the PLTD-NP possesses adequate biosafety, both before and after irradiation. Overall, the incorporation of P-3CP with biorenewable LA-based monomer adheres to the principles of green chemistry, significantly simplifying the synthetic pathway of light-responsive polymers. [ABSTRACT FROM AUTHOR]

ABSTRACT A polystyrene- block-poly(methyl methacrylate) (PS- b-PMMA) exhibiting a well-defined structure was prepared combining anionic polymerization and mercaptan/ε-caprolactam living polymerization. To evaluate how this block copolymer affected the crystallization of polylactide (PLA), 0.5 wt % thiol-terminated PS homopolymer (PSSH), PMMA, and PS- b-PMMA was melt-blended with PLA. The calorimetric characterization of the nonisothermal and isothermal crystallization behavior was analyzed according to Avrami's theory, indicating that PS- b-PMMA more effectively increased the crystallization kinetics of the PLA matrix than did PSSH or PMMA. The results revealed that the synergistic effect of the PS and PMMA blocks appeared only when they were simultaneously presented in the PLA matrix. The PS block increased the number of nucleation sites and decreased the spherulite size, whereas the PMMA block facilitated the excellent dispersion of PS- b-PMMA in the PLA matrix as shown in polarizing optical microscope experiments. Incorporating PS- b-PMMA improved the PLA crystallization rate by promoting heterogeneous nucleation. In addition, incorporating 0.5 wt % PS- b-PMMA increased the relative crystallinity of PLA to 43.5%, and decreased the crystallization half-time to 2.4 min when the blend was isothermal at 105 °C. The PLA crystal structure was unchanged by the presence of PS- b-PMMA; however, the crystallization rate was enhanced as probed by SEM and X-ray diffraction. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 823-832 [ABSTRACT FROM AUTHOR]

Significant progress has been achieved for all-polymer solar cells (APSCs) in the last few years by the use of polymerized small molecular acceptors (PSMAs). Developing high electron mobility polymer acceptors has been considered a feasible solution to further improve the photovoltaic performance of APSCs and fabricate thick film devices, which contributed to roll-to-roll printing techniques. In this work, we designed and synthesized PSV, an A-DA'D-A small molecule acceptor-based PSMA with the vinyl group as a bridged linkage to reduce the steric hindrance between the 1,1-dicyanomethylene-3-indanone (IC) terminal group. In comparison with the C-C bond linked polymer acceptor PS, PSV exhibits an almost planar conjugated framework and well-ordered molecular stacking in the thin film. Moreover, PSV exhibits superior n-type semiconducting properties with high electron mobility of up to 0.54 cm2·V−1·s−1, which is the highest value among reported PSMAs. By utilizing PM6 as a polymer donor, PSV-based blend forms a favorable nanomorphology and exhibits high and well-balanced hole/electron mobilities, which is beneficial for exciton separation and charge transport. Consequently, APSCs based on PM6:PSV achieved high power conversion efficiencies of up to 15.73%, with a simultaneously realized high Voc of 0.923 V, Jsc of 23.2 mA·cm−2, and FF of 0.734. Such superior features enable PSV with excellent thickness-insensitive properties and over 13% PCE was obtained at 300 nm. To the best of our knowledge, the high PCE of 15.73% with excellent electron mobility of 0.54 cm2·V−1·s−1 is the highest values reported for APSCs. These results point to the great significance of developing polymer acceptors with a high electron mobility for boosting the performance of APSCs. [ABSTRACT FROM AUTHOR]

Abstract: Coaxial heterojunction polymer solar cells consisting of vertical aligned crystalline TiO2 nanotube arrays transferred onto FTO-coated glass and ordered interpenetrating poly(3-hexylthiophene-2,5-diyl) (P3HT) have been fabricated through interface sensitization of CdS quantum dots on TiO2 nanotube walls. The performances of structurally identical polymer solar cells with and without CdS quantum dots sensitization were investigated and compared. The sensitized P3HT/CdS-TiO2 cell demonstrated an open-circuit photovoltage of 0.72V and a short-circuit current of 8.29mA/cm2 while the P3HT/TiO2 cell was 0.41V and 5.64mA/cm2. The efficiency of this sensitized cell represents a more than four-fold improvement compared to the non-sensitized cell. By probing the charge transport characteristics at interfaces and the mechanism of photoelectric conversion, it is found the moderately interfacial CdS QDs plays the role of assisting charge separation and suppression of back recombination at interfaces, which accounts for the observed enhanced J sc and V oc in photovoltaic performance. [Copyright &y& Elsevier]

Abstract: Preparation of Ag dendrites on the surface of chelating copolymer membranes (PBAGI), which was synthesized by using the soap-free emulsion copolymerization of n-butylacrylate (BA) and acrylonitrile (AN), as well as 2-methacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester (GMA-IDA) that was used as a chelating group, is presented in this study. The characteristics of polymer membranes were investigated by Fourier transform infrared (FTIR) spectroscopy and elementary analysis (EA). The weight fraction of GMA-IDA in the polymer was 4.2wt% as revealed by elemental analysis. The chelating group, –N(CH2COO−Na+)2 on the polymer was used to coordinate different amounts of Ni(II), controlled by different chelating times and subsequently reduced to Ni nanoparticles, as templates for growing Ag nanocrystals from 1.67wt% AgNO3 aqueous solution with 55.7 ppm poly(vinyl pyrrolidone) (PVP) added. In addition, the effect of Ni2+ concentration on the growth of the Ag dendrites was studied. Crystallinity and morphology of Ag dendrites were examined with X-ray diffraction (XRD) and scanning electronic microscopy (SEM), respectively. Amount of Ag dendrites increased with the increasing of Ni nanoparticles on the PBAGI membrane or the dose of Ni2+ present in the aqueous solution. Notable, under higher amount of Ni nanoparticles (over 200mmol Ni2+/g PBAGI membrane), Ag dendrites could be successful grown on the membrane. However, higher dose of Ni2+ (over 41.3ppm) might inhibit the growth of Ag dendrites. [Copyright &y& Elsevier]

Abstract: An electrospinning process was used to fabricate cobalt ferrite (CoFe2O4)-embedded polyacrylonitrile (PAN) nanofibers. Oleic acid-modified CoFe2O4 nanoparticles were dispersed in the PAN before spinning. The surface morphologies and structures of the nanofibers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and TEM observation showed that the average diameter of the CoFe2O4/PAN nanofibers was 110nm, and the magnetic CoFe2O4 nanoparticles were embedded in the PAN nanofibers. X-ray photoelectron spectroscopy was used to characterize the CoFe2O4/PAN and CoFe2O4/carbon nanofibers. Fiber magnetic properties were measured by vibrating sample magnetometry, showing that the saturation magnetization of the CoFe2O4/PAN nanofibers was 45emu/g and that the fibers demonstrated superparamagnetic behavior. [Copyright &y& Elsevier]

Abstract: A series of polyimide-based nanocomposites containing modified multi-walled carbon nanotubes (mCNT) has been prepared. The multi-walled carbon nanotubes (CNT) were modified by plasma treatment and maleic anhydride was grafted onto them. After plasma modification, the mCNT showed good dispersal in the polyimide matrix and imparted excellent mechanical properties. The mechanical properties, including Young’s modulus, tensile strength, and elongation, were improved with increasing added mCNT content in the range 0.01–0.5wt.%. DMA measurements clearly showed that the glass transfer transition temperature (T g) increased with increasing mCNT content. In addition, the electrical conductivities of the mCNT/polyimide nanocomposites exceeded 10−4 S/cm. These results indicate that the mCNTs incorporated into the polyimide matrix not only provided a path for electron transfer, but also effectively reinforced the polyimide matrix. [Copyright &y& Elsevier]

Abstract: One-dimensional TiO2 nanoparticles within polyvinylpyrrolidone (PVP) fiber matrices were prepared via coupling sol–gel method and electrospinning. TEM analysis indicated that TiO2 nanoparticles chain was in the middle of PVP fiber and dispersed linearly along the fiber direction, which originated from the effect of polarization and orientation caused by high electric field. With the increase of the concentration of sol–gel precursor in the electrospinning solution, the diameter of nanoparticles in resulting fibers decreased from 60 to 13 nm. This composite nanomaterial will have potential applications in photoluminescent (PL), electroluminescent (EL) and non-linear optical devices, flat panel displays, photocathodes for solar and so on. [Copyright &y& Elsevier]

Abstract: A new double bitrack Cu–N coordination polymeric chain-modified Wells–Dawson POMs, [Cu(4,4′-bipy)]2[H4P2W18O62]·2H2O (1), has been synthesized and characterized by IR, TG and single crystal X-ray diffraction. It represents the first example that saturated Wells–Dawson POMs are covalently linked by transition metal coordination polymers into a 3D structure. Additionally, its electrochemical property has been studied, undergoing three two-electron reversible redox processes. [Copyright &y& Elsevier]

Abstract: A block copolymer polyacrylonitrile-b-polyethylene glycol was synthesized by the macroinitiator method. The copolymer mixed with a plasticizer—propylene carbonate (PC) and LiClO4 to form plasticized polymer electrolytes. FT-IR spectra show that the lithium ion interacts with the groups that contain the un-bonded electrons. The results of FT-IR also indicate that the EO segment can improve the dissociation of lithium salt. The differential scanning calorimeter (DSC) used to study the thermal behaviors of different compositions. In this study, the conductivity increases with the content of PEG. Additionally, the plasticized polymer electrolyte based on the block copolymer has a good conductivity and can retain good mechanical strength. [Copyright &y& Elsevier]

Abstract: A series of PAN-based pre-carbonized fibers were prepared in pilot carbonization line at gradient temperature of 350–600°C. DSC, FTIR, X-ray diffraction, EPR and elemental analysis were used to study the evolution of chemical structures in these pre-carbonized fibers. At the same time, the reaction mechanism during the pre-carbonization was also explored. According to the chemical structural changes, the process of pre-carbonization below 600°C can be divided into three stages. Below 450°C, cross-linking and aromatization are the main reactions accompanied by heat liberation and rearrangement of oxygen-containing groups. But around 500°C the pyrolysis reactions acquire the priority and the aromatization structure is dominant in the fibers. Until 600°C the ladder polymers cross-link to form the carbon basal planes, resulting in the growth of aromatization structures. Based on the dependence of fiber structure on temperature, the pre-carbonization technology was optimized. [Copyright &y& Elsevier]

Carbohydrates are involved in a wide range of biological processes. These structurally diverse compounds are more complex than other biological polymers, and are often present as heterogeneous mixtures in nature. The chemical synthesis of carbohydrates is one way to obtain pure oligosaccharides, but it is hampered by difficulties associated with the regioselective protection of polyhydroxyls and challenges related to the stereoselective assembly of glycosidic linkages. Here we describe a combinatorial, and highly-regioselective, method that can be used to protect individual hydroxy groups of a monosaccharide. This approach can be used to install an orthogonal protecting group pattern in a single reaction vessel (a ‘one-pot’ reaction), which removes the need to carry out the time-consuming isolation and purification of intermediates. Hundreds of building blocks have been efficiently prepared starting from d-glucose, and the iterative coupling of these building blocks enabled us to assemble β-1,6-glucans and a library of oligosaccharides based on the influenza-virus-binding trisaccharide. [ABSTRACT FROM AUTHOR]

Abstract: Two kinds of polymer–metal compounds, heterogeneous complexes (metal-chelating copolymer microspheres, MCP) and homogeneous complexes (water-soluble metal-chelating polymers, WSMCP), were synthesized to act as nucleation agents for YIG precursor preparation in this text. Both of the metal-chelating polymers have the same chelating group and high metal ion adsorption ability from the FTIR and ICP measurement. Furthermore, good YIG crystals can be obtained by treating the MCP precursor with a low calcination temperature at 600 °C from the XRD spectra and TEM micrograph. However, the YIG crystal obtained using a WSMCP precursor should be synthesized at a higher calcination temperature (>900 °C) due to the different components of the YIG precursor. In addition, the YIG crystal obtained by using the MCP precursor had nearly superparamagnetic behavior after VSM examination. [Copyright &y& Elsevier]

Abstract: Chelating poly(acrylates-co-2-methylacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester) microspheres of diameter 250–310 nm were prepared by the soap-free emulsion polymerization method for varying amounts of GMA-IDA. Then CdS/copolymer composite was generated by chemical deposition on the surface of the copolymer microspheres. By XRD analysis it is found that the chelated CdS nanoparticles are a pure cubic zinc blende structure. The CdS/copolymer composite is examined by UV–vis absorbance, photoluminescence, and TEM observation. Average CdS nanoparticle size calculated from Henglein''s empirical curve is in the range of 3.0–8.0 nm and varies according to the GMA-IDA molar ratio during polymerization, pH value during chelation, and postchelation annealing temperature. Higher ratio of chelating group, pH value, and annealing temperature produce larger CdS nanoparticles. As GMA-IDA ratio increases, photoluminescence exhibits a red shift from 510 to 520 nm, photoluminescence increases, and bandwidth decreases. Photoluminescence of the CdS nanoparticle becomes negligible when diameter exceeds 5 nm. [Copyright &y& Elsevier]

Abstract: The effects of gel polymer with chelating groups on polymer matrix were been characterized by differential scanning calorimeter (DSC) and Fourier transform infrared spectroscopy (FT-IR). The mechanical properties were elucidated using an Instron instrument. The gel polymer, poly(AN-co-GMA-IDA), was made by the copolymerizing acrylonitrile (AN) and (2-methylacrylic acid 3-(bis-carboxymethylamino-2-hydroxy-propyl ester) (GMA-IDA), mixing the product with a plasticizer—propylene carbonate (PC). In a study on gel-type polymer electrolytes, lithium perchloride was doped into the gel polymer. FT-IR and 7Li solid-state NMR spectra elucidate the interactions between lithium ions and the unpaired electrons on the groups based on the gel polymer. Additionally, the 7Li solid-state NMR reveals that lithium ions are preferentially coordinated with the GMA-IDA segments. The glassy transition temperature (T g) of the gel-type polymer electrolyte increases with the doping of LiClO4, indicating interactions among lithium ions, the plasticizer (PC) and the copolymer. The Arrhenius-like behavior of the conductivity reveals that the charge carries move in a liquid-like environment. The maximum conductivity in this investigation is 2.17×10−3 Scm−1. The GMA-IDA unit in the gel-type polymer electrolytes improves the dissociation of the lithium salt and the mechanical strength and conductivity of the electrolytes. [Copyright &y& Elsevier]

Abstract: This study proposes new method for preparing hybrid CdS nanoparticles in poly(BA-co-GMA-co-GMA-IDA) (PBGM) copolymer membranes with controllable size. PBGM membranes were prepared by soap-free emulsion copolymerization of n-butylacrylate (BA), glycidyl methacrylate (GMA) and 2-methacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester (GMA-IDA). GMA-IDA chelating groups within the copolymer were the coordination sites for chelating Cd2+, at which nano-sized CdS nanoparticles were grown. The GMA-IDA mole fractions in PBGM1, PBGM2, and PBGM3 were 3.97%, 6.41%, and 8.79%, respectively, as determined by elemental analysis. Fourier transform infrared spectroscopy spectra were used to elucidate the characteristics of GMA-IDA in PBGM membranes. The size distribution, morphology, and structure of CdS nanoparticles were measured by transmission electron microscopy (TEM) and X-ray diffraction. TEM observations reveal that the mean diameters of CdS nanoparticles can be controlled between 3nm and 6nm inside the matrix of the PBGM membranes. The UV–vis absorption spectra provide information on the absorption edges, band-gaps and mean diameters, the results of which are consistence with the TEM observations. Photoluminescence spectra show the characteristics of excitation absorption of the hybrid membranes. Scanning electron microscopy images reveal the different sizes distributions of CdS nanoparticles on the surfaces. [Copyright &y& Elsevier]

The kinetics of suspended emulsion polymerization of methyl methacrylate (MMA), in which water acted as the dispersed phase and the mixture of MMA and cyclohexane as the continuous phase, was investigated. It showed that the initial polymerization rate (Rp0) and steady-state polymerization rate (Rp) were proportional to the mass ratio between water and oil phase, and increased as the polymerization temperature, the potassium persulphate concentration ((I]) and the Tween20 emulsifier concentration ([S]) increased. The relationships between the polymerization rate and [I] and [S] were obtained as follows: Rp0 ∞ [I]0.73[S]0.32 and Rp ∞ [I]0.71[S]0.23. The above exponents were close to those obtained from normal MMA emulsion polymerization. It also showed that the average molecular weight of the resulting poly(methyl methacrylate) decreased as the polymerization temperature, [I] and [S] increased. Thus, MMA suspended emulsion polymerization could be considered as a combination of many miniature emulsion polymerizations proceeding in water drops and obeyed the classical kinetics of MMA emulsion polymerization. [ABSTRACT FROM AUTHOR]

Selectivity sorption and permeation of molecular oxygen are described for 2-methylacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester cobalt(II) coordinated with rubbery copolymer membranes. Rubbery copolymers with different highly chelating group contents are prepared by using soap-free emulsion copolymerization. Amounts of cobalt(II) ion adsorbed by the rubbery copolymer membranes are in the range of 0.7–2.0 wt.%, in other words, cobalt(II)-complex contents in membranes are up to ca. 12 wt.%. The cobalt(II)-complex in membranes is a kind of highly oxygen-affinity material as well as rapid and reversible oxygen adsorption/desorption behavior showing. IR results of the oxygen-binding cobalt(II)-complexes show evidence for formation of mononuclear superoxo complexes. Sorption isotherms of oxygen for the membranes are analyzed with a dual-mode sorption model to give CC′ (the saturated amount of oxygen reversibly bound to the cobalt(II) sorption site) and K (the oxygen-affinity constant of cobalt(II)-complex). The oxygen permeability of the membrane containing cobalt(II)-complex increased with decreasing upstream oxygen pressure, which is in accordance with a dual-mode transport model. Moreover, the oxygen permeability/selectivity combinations are above and to the right of the “upper bound” line as the cobalt(II) contained as much as 1.7 wt.% (cobalt(II)-complex 12.3 wt.%) in membrane under high upstream oxygen pressure (Pu≤2 atm), however, the best oxygen permeability and selectivity combinations in this study are as high as 11.2/10.3 under Pu=0.5 atm, respectively. [Copyright &y& Elsevier]

For totally disordered organic polymer films, charge mobility is low, while the mobility significantly increases if the polymer exhibits self-assembling properties that can be exploited to generate ordered structures. Introducing a hydrogen-bonding functionality in the materials, resulting in hydrogen-bonded material superstructures, can be a suitable method to fulfil those critical requirements. To the best of our knowledge, the chromophores with hydrogen bonding ability are rarely investigated. Quinacridone (QA) with large π-conjugation system, planar structure as well as the amide and carbonyl groups, is attracted our attention. The hydrogen bonding association (NH...OC) can be formed between the amide groups and the carbonyl units from the QA core. In this work, the QA chromophore is, for the first time, introduced as the electron withdrawing unit in donor-acceptor type polymers for semiconductors. The hydrogen bonded polymers exhibit significantly large red shifted up to 192 nm, which indicates that the hydrogen bonding association in the QA system is powerful. In addition, the hydrogen bonding association led to the polymers not only from a disorder state and inferior crystallinity transferring into a more ordered structures with a block- or fiber-liked-shaped crystalline, but also a strong aggregation. This observation is beneficial for the hole transporting between the neighboring molecules. In addition, the HOMO energy levels have been improved after the hydrogen bonding association formation, which is advantage for the Ohmic contact formation. As a consequent, the hole transport mobility is significantly improved from 0.13 cm2 V−1 s−1–1.02 cm2 V−1 s−1. This work demonstrate that QA is a novel and promising electron-deficient building block with potential strong hydrogen bonding association for the high-performance semiconductor. [Display omitted] • Hydrogen bonded self-assembled quinacridone (QA) based polymers are designed and synthesized. • The HB polymers exhibit a significantly large red shifted up to 192 nm indicating a strong hydrogen bonding association. • HB induced the hole transport mobility is significantly improved from 0.13 cm2 V−1 s−1–1.02 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

A series of thienoisoindigo (TIG)‐based conjugated polymers (CPs) with high molecular weights are synthesized by direct arylation polycondensation (DArP) by using TIG derivatives as CBr monomer and multi‐halogenated thiophene derivatives, i.e., (E)–1,2‐bis(3,4‐difluorothien‐2‐yl)ethene (4FTVT), (E)–1,2‐bis(3,4‐dichlorothien‐2‐yl)ethene (4ClTVT), 3,3',4,4'‐tetrafluoro‐2,2'‐bithiophene (4FBT), and 3,3',4,4'‐tetrachloro‐2,2'‐bithiophene (4ClBT), as CH monomers. Density functional theory (DFT) calculations reveal the high selectivity between α‐CH bonds in 4FTVT, 4ClTVT, 4FBT, and 4ClBT and β‐CH bonds in TIG CBr monomer. All four resulting CPs exhibit low optical bandgaps of ca. 1.20 eV and ambipolar transport characteristics with both electron and hole mobility above 0.1 cm2 V−1 s−1 as elaborated with organic thin‐film transistors (OTFTs). The polymer TIG‐4FTVT delivers the best device performance. With this polymer, n‐channel OTFTs with electron mobility up to 1.67 cm2 V−1 s−1 and p‐channel OTFTs with hole mobility up to 0.62 cm2 V−1 s−1 are fabricated by modifying source/drain electrodes with polyethylenimine ethoxylated (PEIE) and MoO3, respectively, to selectively inject electrons and holes. [ABSTRACT FROM AUTHOR]

A green methodology for the production of polymers from bamboo powder was investigated. The optimal conditions for the extraction of components from bamboo were defined by incubating the powder in an acetate buffer (pH 5) under boiling for 2 h. Native laccase from Myceliophthora thermophila was used afterwards to oxidize the extracts from the final resulting extraction liquid. The reduction of the free OH content after enzymatic oxidation, as well as the 1H NMR data, confirmed the efficient polymerization of the extracts. The bamboo powder samples were also subjected to high compression and curing, in the absence and in the presence of laccase, to evaluate the hardness of the tablets formed by enzymatic bonding events. The results revealed a higher hardness when the tablets were produced in the presence of laccase, confirming the role of the catalyst on the precipitation of colloidal lignin and phenolic extractives. Herein we produce new oligomers/polymers by laccase oxidation of the extracts resulting from a clean method boiling. At the same time, the data open up new routes for the exploitation of new lignocellulosic materials by the direct application of the enzyme on the bamboo powder material. [ABSTRACT FROM AUTHOR]

Developing plastics that can integrate mechanical (strength and toughness) and dynamic properties (recyclability, repairability, and biodegradability) is commonly challenging. In this work, inspired by the reinforced concrete structure, an ultra-strong and ultra-tough sustainable polymer composite was constructed through uniformly dispersing cellulose nanofiber in a poly(vinyl alcohol) matrix to form a bicontinuous interwoven network structure based on strong yet dynamic hydrogen bonding crosslink sites. The obtained composite showed an ultra-high toughness, a high tensile fracture strength, good Young's modulus and transparency, as well as excellent dynamic properties including good healing ability, recyclability, and biodegradability. Besides, with excellent gas barrier ability and good water vapor permeability, the composite showed great promise to replace traditional polymers for food packaging and preservation. At last, the mechanism behind the good performances is expected to inspire the design of other healable and green polymers in the future. [Display omitted] • A PVA-CNF composite has a bicontinuous interwoven network with strong, dynamic hydrogen bonding crosslink sites. • The tensile strength and toughness of the PVA matrix are increased by 194% and 994% with 3 wt% CNF incorporating. • Good repairable efficiency of PVA-CNF composites is enabled by the dynamic hydrogen bonds. • The PVA-CNF composites exhibit excellent recyclability and biodegradability. [ABSTRACT FROM AUTHOR]

The cover picture shows fundamental passive circuit elements of resistor, capacitor, inductor and memristor, and the correlations between the circuit variables. Memristor has been considered capable of mimicking the function of a mammalian synapse with the ability to learn and memorize new information, and to allow powerful and energy‐efficient processing capability for complex open‐ended computing tasks. Details are given in the Full Paper on page 1263 ff. by Y. Chen and co‐workers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • We prepared the planar D/A interface to exclude complexity in the BHJ interface. • We systematically investigated the effects of interfacial energy band alignments by UPS and SKPM. • The E gap values were increased by interfacial dipole, causing larger voltage loss than expected. Abstract In organic photovoltaic (OPV) devices, the open-circuit voltage (V oc) is one of the most important parameters that determines the device performance. Generally, the maximum value of V oc is set by the energy gap (E gap). However, the E gap value of the active layer of an operating device will deviate from that based on the energy levels of the individual materials due to the occurrence of complicated interfacial physical and chemical interactions. Here, we systematically investigated the effects of the interfacial energy band alignment with different polymer donors and small-molecule acceptors. The E gap values increased in the presence of an interfacial dipole, leading to a larger voltage loss (Δ) than expected. [ABSTRACT FROM AUTHOR]

Building polymers are highly flammable and produce a vast amount of toxic chemical compounds in the event of a fire which can lead to potential incapacitation and death. To gain an in-depth understanding of this issue, smoke toxicity and thermal characteristics of seven commonly used building polymers were analysed through a systematic fire performance evaluation system using a Thermogravimetric Analyzer and a Cone Calorimeter coupled with an FTIR arrangement. Four Fractional Effective Dose (FED) expressions were compared to assess the smoke toxicity of the fire effluents based on different assumptions. It was found that FEDN2, calculated using Purser's equation, reported the highest values of FED with the following order of potential smoke toxicity at 50 kW/m2 radiative heat flux: LDPU > HDPU > PE > HDEPS > XPS > EVA > LDEPS. Furthermore, fire performance evaluation of the polymers was carried out by considering three key fire risk parameters, i.e., flashover propensity, total heat released, and toxic hazard. At 50 kW/m2 radiative heat flux, HDPU exhibited 11.7 times flashover propensity compared to the least flammable polymer (HDEPS), EVA exhibited 5 times total heat release compared to the polymer with the lowest total heat release (LDEPS) and, LDPU exhibited 6.7 potential times toxic hazard compared to the least toxic polymer (EVA). [ABSTRACT FROM AUTHOR]

Multi‐level memory can greatly improve information density, so it has been widely studied. In this study, a carbazole‐based donor–acceptor polymer poly[2,7‐9‐(heptadecan‐9‐yl)‐9H‐carbazole‐alt‐7H‐benzimidazo[2,1‐a]benz[de]isoquinolin‐7‐one] (PCz‐BB) is synthesized, which exhibits flash‐type ternary memory behavior. Further, CdS nanoparticles (NPs) are embedded into the prepared polymer to enhance the storage performance. The current–voltage (I–V) characteristics of memory devices based on PCz‐BB:CdS composites and the effect of the embedding ratio of CdS NPs on the memory devices are studied. It is verified that the ON2/ON1/OFF current ratios of the devices at low CdS embedding concentrations are improved, and the threshold voltages are also reduced. The memory device based on the optimal embedding concentration (3 wt% CdS) exhibits a high ON2/ON1/OFF current ratio of 18631:72:1, a low threshold voltage of −0.40/−1.20 V, and excellent stability. The mechanism of resistive switching is explained by the theory of charge traps and conductive filaments. This work provides a new avenue for high‐performance multi‐level organic electrical storage materials. [ABSTRACT FROM AUTHOR]

Invited for this month's cover is the group of Prof. Dr. Yu Chen from East China University of Science and Technology, P. R. China. The cover picture shows fundamental passive circuit elements of resistor, capacitor, inductor and memristor and the correlations between the circuit variables. Read the full text of the article at [ABSTRACT FROM AUTHOR]

Resonant Soft X-ray Scattering (RSoXS) was developed over the last a few years, and the first dedicated resonant soft X-ray scattering beamline for soft materials was constructed at the Advanced Light Source, LBNL. RSoXS combines soft X-ray spectroscopy with X-ray scattering and thus offers statistical information for 3D chemical morphology over a large length scale range from nanometers to micrometers. Using RSoXS to characterize multi-length scale soft materials with heterogeneous chemical structures, we have demonstrated that soft X-ray scattering is a unique complementary technique to conventional hard X-ray and neutron scattering. Its unique chemical sensitivity, large accessible size scale, molecular bond orientation sensitivity with polarized X-rays, and high coherence have shown great potential for chemically specific structural characterization for many classes of materials. [ABSTRACT FROM AUTHOR]

A correction to the article "Preparation of High Photoluminescent Hybrid Polymer-CdS Nanoparticle with Chelating Functional Polymer" is presented.

The charge transport ability of polymer acceptors (PAs) is crucial for achieving high power conversion efficiencies (PCEs) of all‐polymer solar cells (all‐PSCs). However, the electron mobilities (μes) of most PAs are inferior to those of their small molecule acceptor (SMA) counterparts. Herein, the authors design a new series of the polymerized SMA‐based PAs (Y5‐A‐B), where the donating moiety (A = selenophene (Se)/biselenophene (BiSe)) and the backbone regioregularity (B = In/Mix/Out) are 2D controlled, for enhancing both the μe and PCEs. Interestingly, the effects of regioisomers on the μe and all‐PSC performance are the opposite depending on the donating unit. For the Y5‐Se‐based PAs, the PCEs increase in order of Out (7.52%) < Mix (9.33%) < In (13.38%). In contrast, for the Y5‐BiSe‐based PAs, the PCEs decrease in order of Out (10.67%) > Mix (9.58%) > In (8.52%). These opposite trends in each series originate from the different planarity and intermolecular assembly of PAs depending on the regioregularity. Thus, the Y5‐Se‐In blend exhibits the highest μe and achieves the highest PCE (13.38%) among the all‐PSCs in this study. Therefore, the authors report the importance of simultaneous engineering of the backbone building unit and regioregularity to realize high‐mobility PA and highly efficient all‐PSCs. [ABSTRACT FROM AUTHOR]

The limited capacity of binary memory may not meet the requirements of future information storage; hence, multilevel memory is widely studied. Herein, a donor–acceptor-type polymer poly[2,7-9-(heptadecan-9-yl)-9H-carbazole-alt-7H-benzimidazo[2,1-a]benz[de]isoquinolin-7-one] (PCz–BMBI) was synthesized using the Suzuki cross-coupling reaction and characterized. The organic resistive random access memory (ORRAM) devices with a non-volatile ternary memory behavior, based on PCz–BMBI and PCz–BMBI:CuO NP active layers, were fabricated using the spin-coating technique. The I–V characteristics of the devices were studied, and the effect of the embedding ratio of CuO nanoparticles (NPs) on the memory performance of the devices was discussed. The results indicate that the switching ratios of all devices with CuO NPs embedded were improved, and their first threshold voltages were lowered. Furthermore, the devices fabricated with an embedding ratio of 7 wt% CuO NPs exhibited optimal memory performance with a current ratio of ON2/ON1/OFF (105.3 : 102.3 : 1) and low threshold voltages (−0.50 V/−1.60 V). This work provides a new route for multi-level storage materials and new ideas for the application of CuO NPs in the field of information storage. [ABSTRACT FROM AUTHOR]

The fabrication of fire-safe, robust yet tough polymeric materials represents a challenge for both academia and industry. In this work, a novel hyperbranched polymer (TP) based on trihydroxymethylphosphine oxide and phenylboronic acid for epoxy resin is described. The presence of 2 wt% TP afforded epoxy blend with a high limiting oxygen index of 33.2%, a UL-94 V-0 rating, 36.3% and 13.7% reductions in peak heat release rate and total smoke production, making it superior to previously described counterparts. The high efficiency of TP may be mainly attributed to its promotion of carbonization. Notably, an epoxy thermoset is strengthened and toughened due to the introduction of TP. The presence of 4 wt% of this additive increased the tensile strength, elongation at break, impact strength, and flexural strength by 54.0%, 32.8%, 32.0% and 36.9%, respectively. In addition, the high transparency of the epoxy thermoset is maintained in the presence of TP. Thus, this approach offers an integrated design for the preparation of transparent, fire-safe, strong but tough epoxy thermoset via the introduction of a hyperbranched polymer. It may be expected that this technique will find wide application in different industrial fields. [Display omitted] [ABSTRACT FROM AUTHOR]

Two-photon induced polymerization for three-dimensional (3D) printing has attracted increasing attention. Here, we report the two-photon induced polymerization of triethylene glycol divinyl ether (TEGDVE) in a porous polymer film using 4,4′,4′′-nitrilotribenzoic acid (NTB) as the photosensitizer and diphenyliodonium hexafluorophosphate (HIP) as the initiator, enabling the printing of multi-layer structures in the porous support. [ABSTRACT FROM AUTHOR]

Liquid crystalline (LC) polymers with a shish-kebab-type moiety on their cross-conjugated ( p-phenylene)s-poly( pphenylenevinylene) s main chains were synthesized through Gilch polymerization in order to develop a kind of polymers available for linearly polarized white-light-emitting from single chain. In this system, the 2,5-bis(4′-alkoxyphenyl)benzene as the 'kebabs' connects with poly( p-phenylenevinylene) (PPV) main chain backbone using its molecular gravity center and the PPV as the 'shish' or 'skewer' (the 'shish-kebab'). The polymers possess desirable properties such as excellent solubility and liquid crystalline properties. To drop the 'kebabs' of the 2,5-bis(4′-alkoxyphenyl)benzene into the orientation microgroove of aligned polyimide film, not only the 'shish' of polymer main chain can be aligned by the virtue of orientation of 'kebabs' but also the uniform cross-conjugated structure between the 'kebabs' and 'shish' can be broken. Then, the alignment of the polymer main chain showed yellow light emission and was also accompanied by orientation of the LC side chains showing blue light emission, this gave rise to a notable linearly polarized white fluorescence. [ABSTRACT FROM AUTHOR]

Abstract: Poly(AN-co-GMA-IDA) has been prepared by copolymerizing acrylonitrile (AN) and 2-methylacrylic acid 3-(bis-carboxymethylamino-2-hydroxy-propyl ester) (GMA-IDA). The polymers were mixed with the plasticizer ethylene carbonate (EC) and lithium perchlorate (LiClO4) to form gel polymer electrolytes (GPE). Fourier-transform infrared spectroscopy (FT-IR) has revealed that the GMA-IDA unit can improve the dissociation of the lithium salt. Furthermore, the GMA-IDA can hinder the crystallization of EC, thereby improving the conductivity of the GPE. This has been established by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. The interaction between GMA-IDA and EC has been confirmed by FT-IR and 7Li solid-state NMR. The maximum conductivity measured in this investigation was 9.75×10−4 Scm−1. [Copyright &y& Elsevier]

Abstract: Ultrafine polyvinylpyrrolidone (PVP)/poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) composite fibers were successfully prepared by electrospinning of PVP/MEH-PPV blend solutions in solvent mixtures of 1,2-dichloroethane/chlorobenzene. Composite polymer fibers with smooth surface were obtained using solutions in which MEH-PPV''s concentration was 1.0 (wt.%). Compared with the MEH-PPV solution and bulk, PVP/MEH-PPV fibers show a significant blue shift, a stronger intensity of fluorescence and a higher surface photovoltage (SPV). The morphology of fibers has been characterized by scanning electron microscopy (SEM) and fluorescence microscopy. [Copyright &y& Elsevier]

Abstract: A new photoluminescent heterobimetallic Zn(II)–Ag(I) cyano-bridged coordination polymer, [Ag5Zn2(tren)2(CN)9] (tren=tris(2-aminoethyl)amine) (1), has been synthesized and structurally characterized. It features rare linear pentameric unit of dicyanoargentate(I) ions assembled by d10–d10 interaction as building blocks. Solid state emission spectrum of 1 shows strong ultraviolet luminescence with emission peak in the range of 376nm. [Copyright &y& Elsevier]

For polymer semiconductors, the backbone structure plays an essential role in determining their physicochemical properties and charge transport behaviors. In this work, two donor–acceptor‐type polymers (P‐BDF and P‐NDF) based on benzodifuranone (BDF) and naphthodifunarone (NDF) as electron‐deficient moieties and indaceno‐dithiophene as electron‐rich groups are designed, synthesized and, for the first time, applied in organic field‐effect transistor. P‐BDF and P‐NDF differ from their backbone structures while P‐BDF has a more planar backbone conformation due to its smaller conjugated core size and P‐NDF features a perpendicular‐extended main chain structure. As a result, P‐BDF polymer exhibits bathochromic optical absorption, deeper molecular orbital energy levels, and more importantly, closer π‐stacking and stronger aggregation in the solid state and thus affords a more promising hole mobility of up to 0.85 cm2 V−1 s−1 in OFET devices, while that of the P‐NDF‐based devices is only 0.55 cm2 V−1 s−1. The results suggest the great potential of BDF/NDF‐type chromophores in constructing novel organic semiconductors and also indicate that the main chain coplanarity of polymer semiconductors is more essential than the sole extension of π‐conjugations (especially at the perpendicular direction of polymer main chains) for the design of high‐performance OFET materials. [ABSTRACT FROM AUTHOR]

All‐polymer solar cells (all‐PSCs) are a highly attractive class of photovoltaics for wearable and portable electronics due to their excellent morphological and mechanical stabilities. Recently, new types of polymer acceptors (PAs) consisting of non‐fullerene small molecule acceptors (NFSMAs) with strong light absorption have been proposed to enhance the power conversion efficiency (PCE) of all‐PSCs. However, polymerization of NFSMAs often reduces entropy of mixing in PSC blends and prevents the formation of intermixed blend domains required for efficient charge generation and morphological stability. One approach to increase compatibility in these systems is to design PAs that contain the same building blocks as their polymer donor (PD) counterparts. Here, a series of NFSMA‐based PAs [P(BDT2BOY5‐X), (X = H, F, Cl)] are reported, by copolymerizing NFSMA (Y5‐2BO) with benzodithiophene (BDT), a common donating unit in high‐performance PDs such as PBDB‐T. All‐PSC blends composed of PBDB‐T PD and P(BDT2BOY5‐X) PA show enhanced molecular compatibility, resulting in excellent morphological and electronic properties. Specifically, PBDB‐T:P(BDT2BOY5‐Cl) all‐PSC has a PCE of 11.12%, which is significantly higher than previous PBDB‐T:Y5‐2BO (7.02%) and PBDB‐T:P(NDI2OD‐T2) (6.00%) PSCs. Additionally, the increased compatibility of these all‐PSCs greatly improves their thermal stability and mechanical robustness. For example, the crack onset strain (COS) and toughness of the PBDB‐T:P(BDT2BOY5‐Cl) blend are 15.9% and 3.24 MJ m–3, respectively, in comparison to the PBDB‐T:Y5‐2BO blends at 2.21% and 0.32 MJ m–3. [ABSTRACT FROM AUTHOR]

The thermal degradation of poly(n-butyl acrylate) (PBA) has been studied by using thermogravimetry under nitrogen atmosphere. It is found that the thermal degradation of PBA initiated by thiols and #x03B5;-caprolactam has only a one-step degradation mechanism, and the degradation temperatures (360–370 °C) are higher than AIBN system (304 and 361 °C). FT-IR, 1H NMR, and 13C NMR are applied to characterize the polymer structures. The terminal group of the PBA chain has a great influence on the degradation, and the initial degradation does not appear to be ester group scission. In order to determine the effect of terminal groups, several approaches (such as Flynn, Flynn–Wall–Ozawa, and Kissinger methods) have been applied to evaluate the kinetic parameters, including activation energy, frequency factor, and rate constants. These values are compared with those obtained for PBA initiated by AIBN. These results indicate that the end groups do have an influence on thermal stability, and the strength of the effect follows the order –R12>–COOH>–OH>–AIBN. [Copyright &y& Elsevier]

The behavior of lithium ions in a comb-like polymer electrolyte with a chelating functional group has been characterized by differential scanning calorimetry (DSC), AC impedance, 13C and 7Li solid-state nuclear magnetic resonance (NMR) measurements. The comb-like copolymer is synthesized by poly(ethylene glycol) methyl ether methacrylate (PEGMEM) and (2-methylacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester) (GMA–IDA). 7Li solid-state NMR spectra demonstrate the interactions of Li+ ions with both the ether oxygen of the PEGMEM and the nitrogen atom of the GMA–IDA segments. Moreover, 7Li solid-state NMR shows that the lithium ions are preferentially coordinated to the GMA–IDA segment. Moreover, the 13C solid-state NMR spectra for the carbons attached to the ether oxygen atoms exhibited significant line broadening and a slight upfield chemical shift and short TCH when the dopant was added to the polymer. These findings indicate coordination between the Li cation and the ether oxygens in the PEG segment. Tg increases for the copolymers doped with LiClO4. These results indicate the interactions of Li+ with both PEGMEM and GMA–IDA segments form transient cross-links. The Vogel–Tamman–Fulcher (VTF)-like behavior of conductivity implies the coupling of the charge carriers with the segmental motion of the polymer chains. The dependence of the maximum conductivity on the composition of the copolymers and the doping lithium ion concentration was determined. The GMA–IDA unit in the copolymer improves the dissociation of the lithium salt, the mechanical strength and the conductivity. [Copyright &y& Elsevier]

Polyurethaneureas (PUU), which were synthesized from 4,4′-diphenylmethane diisocyanate (MDI), poly(ethylene glycol) (PEG, MW=2000), and 3,5-diaminobenzoic acid, were used as the matrix of the polyelectrolytes in this study. Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and 7Li magic angle spinning (MAS) solid-state NMR were used to monitor changes in the morphology of PUU electrolytes corresponding to the concentration of lithium perchlorate (LiClO4) dopants. The results of DSC and FT-IR indicate the different polymer complexes formed by the interaction of the Li+ ions with the different coordination sites of PUU. The 7Li MAS solid-state NMR investigation of the PUU electrolytes points out that two different Li+ environments exist at lower temperature. The results of DSC and the 7Li MAS solid-state NMR show that Li+ ions are preferentially coordinated to the ether oxygen of the PEG soft-segment when the salt concentration is below 0.1 mmol LiClO4(gPUU)−1. Impedance spectroscopy measurements show that the conductivity behavior followed the Arrhenius equation and was influenced by the hard-segment Tg. One of the PUU electrolytes under the investigation has an ionic conductivity as high as 3.0×10−5 S cm−1 at 30 °C. [Copyright &y& Elsevier]

The behavior of lithium ions in a comb-like polymer electrolyte with a chelating functional group have been characterized by differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) spectroscopy, ac impedance and 7Li solid-state NMR measurements. The comb-like copolymer is synthesized by poly(ethylene glycol-methyl ether methacrylate) (PEGMEM) and (2-methylacrylic acid 3-(bis-carboxymethylamino) -2-hydroxy-propyl ester) (GMA-IDA). FTIR and 7Li solid-state NMR spectra demonstrate the interactions of Li+ ions with both the ether oxygen of the PEGMEM and the nitrogen atom of the GMA-IDA segments. Moreover, 7Li solid-state NMR shows that the lithium ions are preferentially coordinated to the GMA-IDA segment. The Tg increases for the copolymers doped with LiClO4. These results indicate the interactions of Li+ with both PEGMEM and GMA-IDA segments form transient cross-links. The Vogel–Tamman–Fulcher (VTF)-like behavior of conductivity implies the coupling of the charge carriers with the segmental motion of the polymer chains. The dependence of the maximum conductivity on the composition of the copolymers and the doping lithium ion concentration was determined. The GMA-IDA unit in the copolymer improves the dissociation of the lithium salt, the mechanical strength and the conductivity. [Copyright &y& Elsevier]