Nanostructuration of Unsaturated Polyester by All‐Acrylic Block Copolymers, 1 ‐ Use of High‐Molecular‐Weight Block Copolymers

Nanostructuration of maleate and orthophthalic unsaturated polyester (UP) resins was achieved by the use of high molecular weight amphiphilic PBA‐b‐P(MMA‐co‐DMA)₂ triblock copolymers. PBA is fully immiscible in cured UP resins, and the miscibility of P(MMA‐co‐DMA) random copolymers can be ensured with a minimum DMA content of 12 mol‐%. When using the triblock copolymers, fully transparent and nanostructured thermosets are obtained with a minimum DMA content in the outer blocks; the value of which is higher than 12 mol‐% and depends on the UP chemical structure. Finally, the fracture toughness of nanostructured thermoset was evaluated: for a triblock copolymer content as low as 5 wt.‐%, a 50% increase of K_Ic was obtained, as compared to the neat thermoset.

     

Low‐Molecular‐Weight CXCR4 Ligands with Variable Spacers

Low‐molecular‐weight CXCR4 ligands based on known lead compounds including the 14‐mer peptide T140, the cyclic pentapeptide FC131, peptide mimetics, and dipicolylamine‐containing compounds were designed and synthesized. Three types of aromatic spacers, 1,4‐phenylenedimethanamine, naphthalene‐2,6‐diyldimethanamine, and [1,1′‐biphenyl]‐4,4′‐diyldimethanamine, were used to build four pharmacophore groups. As pharmacophore groups, 2‐pyridylmethyl and 1‐naphthylmethyl are present in all of the compounds, and several aromatic groups and a cationic group from 1‐propylguanidine and 1,1,3,3‐tetramethyl‐2‐propylguanidine were also used. Several compounds showed significant CXCR4 binding affinity, and zinc(II) complexation of bis(pyridin‐2‐ylmethyl)amine moieties resulted in a remarkable increase in CXCR4 binding affinity.     

量子点敏化太阳电池光阳极研究进展

在量子点敏化太阳电池的性能研究中,光阳极薄膜的优化一直是研究的重点。除了传统的TiO_2纳米颗粒,通过一些简单实验制备出的纳米管、纳米线阵列,一维核壳纳米结构也被广泛的应用于光阳极中。形貌易于控制的ZnO因与TiO_2具有相似的能带结构和物理性质,又兼具高的电子迁移率而成为比较理想替代物。一维ZnO及其核壳结构半导体材料的制备及性能研究表明,其具有良好的导电性,电荷分离传输效率高,光俘获性能好等优点,已成为量子点敏化太阳电池光阳极研究的重要方向。     

Molecular‐Weight‐Controlled Brittle‐to‐Semiductile‐to‐Ductile Transition in S‐(S/B)‐S Triblock Copolymers

Toughness enhancement of S‐(S/B)‐S triblock copolymers via a molecular‐weight‐controlled pathway is demonstrated. The post‐yield crack toughness behavior of the triblock copolymers uniquely reveal a brittle‐to‐semiductile‐to‐ductile transition with increasing while keeping the basic molecular architecture fixed. TEM and SAXS investigations indicated three distinct morphologies as a function of χ_effN as a consequence of the increase in : (i) a homogeneous structure without phase‐separation, (ii) a weakly segregated structure, and (iii) a lamellar structure. The increase in crack toughness is also reaffirmed from kinetic and strain field analysis studies concerning dynamics of crack growth in block copolymers with high PS content.

     

纳米二氧化钛的水热法制备及在染料敏化太阳能电池中的应用

分别在盐酸和冰醋酸溶液中水解钛酸四正丁酯，得到前驱体，通过水热法制备锐钛矿型二氧化钛纳米晶体．以纳米二氧化钛为电子传输体组装染料敏化电池。通过XRD、ICP、DRS、TEM、SEM和电池的光电性能测试，研究制备的二氧化钛对电池光电性能的影响．结果表明，水热反应温度对染料敏化太阳能电池光电性能有较大影响，在有机酸介质中制备的二氧化钛具有较高的光电转换效率．     

量子点敏化太阳电池对电极研究进展

对电极在量子点太阳能电池中具有重要的作用,本文主要介绍了铂、金属硫化物、金属硒化物和复合材料对电极的发展现状。复合材料对电极由于良好的导电和催化性能,且具有较好的稳定性,已经成为获得具有高光电效率的量子点敏化太阳能电池的重要研究方向。     

染料敏化太阳能电池光阳极的研究进展

介绍了染料敏化太阳能电池(DSSC)的主要结构和基本原理,着重阐述了染料敏化太阳能电池光阳极的最新研究结果,并对几种不同光阳极的优缺点进行了详细的描述。文章指出具有高的比表面积、电荷的快速传输通道以及优越的抑制电荷复合性能的多孔膜是未来DSSC电池光阳极的主要发展方向。     

Effect of nano‐TiO2 dispersion on PEO polymer electrolyte property

Polymer electrolyte membranes based on poly(ethylene oxide) (PEO) doped with TiO₂ nanoparticles were synthesized by simple solution cast technique. Mesoporous TiO₂ film was prepared by doctor‐blade method. The modified polymer membranes and the mesoporous films were characterized by SEM, TEM, AFM, ionic conductivity, and J‐V measurements. Dye‐sensitized solar cells (DSSC) have been fabricated in which PEO‐polymer electrolyte doped with and without nano‐TiO₂ were sandwiched between porous TiO₂ and counter electrodes. The DSSC with nano‐TiO₂ doped polymer electrolyte shows better performance (1.68%) in comparison with pristine polymer electrolyte (1.07%), which is due to improved ionic conductivity value in polymer electrolyte system by nano‐TiO₂ doping. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of quaternized ammonium iodide‐containing conjugated polymer electrolytes and their application in dye‐sensitized solar cells

A series of conjugated polymer electrolytes (CPEs) comprising fluorene/carbazole or thiophene/carbazole backbones with quaternized ammonium iodide groups were synthesized and used in polymer solution and polymer gel electrolytes in dye‐sensitized solar cells (DSSCs). The photovoltaic (PV) performances became markedly poorer with increasing CPE content for the DSSCs based on polymer solution electrolytes. However, the PV performances were not significantly affected with increasing CPE content for the DSSCs fabricated from poly(ethylene oxide) (PEO)/CPE blend‐based gel‐type electrolytes. Moreover, higher PV efficiencies and stabilities were obtained for the DSSCs based on PEO/CPE blend gel electrolytes as compared to the DSSCs based on PEO gel electrolyte. The electrochemical impedance and PV properties of the DSSCs based on polymer solution electrolytes and on polymer gel electrolytes were determined as a function of the CPE concentration. Copyright © 2010 Society of Chemical Industry     

Evaluation of Octyltetramethyldisiloxane‐Containing Ethylene Copolymers as Composite Lubricant for High‐Density Polyethylene

A series of octyltetramethyldisiloxane‐containing ethylene copolymers, poly(ethylene‐co‐OO7) (abbreviated as E‐co‐OO7), are prepared from vanadium catalyzed copolymerization of ethylene with 1‐oct(7‐en)yl‐3‐octyl‐1,1,3,3‐tetramethyldisiloxane (or OO7) macromonomer. The copolymers containing different silicone contents are employed as composite lubricants for high‐density polyethylene (HDPE). The influences of the silicone content in the copolymer and that of the added copolymer amount in the blend on the bulk and surface properties of the blends are systematically investigated. The results show that E‐co‐OO7 exhibits superior overall performance in comparison with conventional lubricants silicone masterbatch and polyethylene wax. Compared to HDPE control, 10 wt% E‐co‐OO7 addition increases the melt flow rates by 49%, increases the elongation at break from 740 to 860%, increases the water‐contact angle from 90° up to 108°, lowers the coefficient of friction from 0.072 to 0.049, lowers the specific wear rate from 11 × 10^?3 to 5.6 × 10^?3 mm³ Nm^?1. The impact strength and high temperature thermal stability are also slightly improved. The measured Si/C atomic ratios demonstrate the sufficient silicone enrichment on surface of the blends. E‐co‐OO7 with 23.5 Si? O? Si per 1000 C gives the best internal lubrication, and E‐co‐OO7 with 29.7 Si? O? Si per 1000 C gives the best external lubrication.

     

Synthesis,properties and self‐assembly of intelligent core‐shell nanoparticles based on chitosan with different molecular weight and N‐isopropylacrylamide

In this study, a series of chitosan‐graft‐poly(N‐isopropylacrylamide) (CTS‐g‐PNIPAAm) copolymers based on different molecular weight (Mw) of CTS and NIPAAm were synthesized through the polymerization of NIPAAm in an acid aqueous solution. The structures were verified by Fourier transform infrared and nuclear magnetic resonance. The influence of the CTS Mw on the properties of the resulting copolymers and self‐assembled nanoparticles was fully examined. The grafting ratio and grafting efficiency of the copolymers increased with the CTS Mw. All the copolymers have a similar low critical solution temperature of 33.5°C, which was independent of the CTS Mw. Furthermore, the copolymers were less temperature sensitive, when CTS Mw increased to 200 kDa. Besides, once the CTS Mw increased to 700 kDa, the copolymers were less pH sensitive near the tumor site (from pH 7.4 to 6.8). The copolymers could form uniform nanoparticles once the temperature increased to 34°C, which was reversible. After crosslinking by N,N‐methylenebisacrylamide (MBA), structurally stable nanoparticles could be obtained. The results from Transmission electron microscope (TEM) and Atomic force microscopy (AFM) showed that the MBA crosslinked nanoparticles were uniformly spherical with a loose structure. Surface tension method indicated that the critical aggregate concentrations were 0.045, 0.042, 0.037, and 0.036 mg mL^?1 prepared from CTS 50, 100, 200, and 700 kDa, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Near Infrared Reflection Spectroscopy: A Versatile Tool for Rapid Characterization of Olefin Copolymers and High‐Throughput Experiments

Near infrared (NIR) spectroscopy was developed as a rapid analytical method for the determination of the composition of olefin copolymers obtained in high‐throughput screening. NIR spectra of ethene/propene and ethene/1‐hexene copolymers, also characterized by means of ¹³C NMR spectroscopy, were recorded and used to design multivariate calibration models. Different methods for the preprocessing of the spectra, including the linearization by non‐linear transformations, were compared. Optimal methods and error estimates were established using crossvalidation. This technique is of particular interest for the rapid on‐line analysis of high‐throughput experiments in the field of polymer and catalyst design employing methods from combinatorial chemistry.

Predicted versus true value of the propene incorporation and standard deviation for ethene/propene copolymers.     

Effects of Eu3+ and Er3+ Doping on Photoelectrical Performance of Dye‐Sensitized Solar Cells

A novel tri‐layer film photoelectrode structure of DSSC by introducing Eu³⁺ and Er³⁺ ions into TiO₂ film was proposed. The photoelectric conversion efficiency of the DSSC with Er³⁺:TiO₂/Eu³⁺:TiO₂/TiO₂ tri‐layer electrode reaches 7.41%, increased by a factor of 1.44 compared to that of the DSSC without Eu³⁺ and Er³⁺ doping. The higher efficiency for DSSC with the tri‐layer electrode is mainly attributed to the down‐conversion luminescence effect by Eu³⁺ ions from ultraviolet light to visible light and up‐conversion luminescence effect by Er³⁺ ions from infrared light to visible light.     

An ionic liquid‐based polymer with π‐stacked structure as all‐solid‐state electrolyte for efficient dye‐sensitized solar cells

An ionic liquid based polymer, poly(1‐ethyl‐3‐(acryloyloxy)hexylimidazolium iodide) (PEAI), was synthesized and employed as electrolyte to fabricate all‐solid‐state dye‐sensitized solar cells. The photophysical properties of PEAI were studied by UV–vis absorption spectroscopy and photoluminescence spectroscopy. PEAI exhibited significant hypochromism and red shift in UV–vis absorption spectra and large Stokes shifts in photoluminescence spectra, indicating the formation of a novel π‐stacked structure in which the imidazolium rings in the side chain were stacked. Without iodine in its preparation, DSC with PEAI electrolyte achieved a conversion efficiency of 5.29% under AM 1.5 simulated solar light irradiation (100 mW cm^?2). The side‐chain imidazolium π‐π stacking in PEAI played a key role in the holes transport from the photoanode to the counter electrode. Both the open‐circuit voltage and short‐circuit current density showed decreases with the increase in the content of iodine in PEAI electrolyte. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of poly(1‐vinyl‐3‐propylimidazolium) iodide for quasi‐solid polymer electrolyte in dye‐sensitized solar cells

The synthesis conditions of ionic liquid 1‐vinyl‐3‐propylimidazolium iodide (ViPrIm⁺I⁻) and Poly(1‐vinyl‐3‐propylimidazolium) iodide [P(ViPrIm⁺I⁻)] were studied in this work. P(ViPrIm⁺I⁻) as a single‐ion conductor providing iodine was designed to develop a quasi‐solid polymer electrolyte based on PVDF/PEO film for dye‐sensitized solar cells (DSSCs). The samples were characterized respectively by high‐performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance imaging (NMRI), gel permeation chromatography (GPC), etc. The results showed that the single‐ion conducting quasi‐solid polymer electrolyte (SC‐QPE) exhibited high ionic conductivity of 1.86 × 10⁻³ S cm⁻¹ at room temperature measured by CHI660C Electrochemical Workstation. Moreover, solar cells assembled using the SC‐QPE yielded an open‐circuit voltage of 0.83V, short‐circuit current of 8.01 mA cm⁻² and the conversion efficiency of 2.42%. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

量子点敏化太阳电池FTO/CoS/CuS对电极的制备与性能

摘要：本文采用恒电位电沉积方法在FTO导电玻璃表面依次沉积CoS和CuS,形成 FTO/CoS/CuS复合对电极用于量子点敏化太阳电池。确定了电沉积电位和电沉积时间,并研究了电沉积温度对电极形貌及电催化活性的影响。对电极的表面形貌和微观结构采用SEM和TEM方法进行表征;对电极的光反射性能采用紫外可见分光光度计进行测试;对电极的电化学性能通过测试交流阻抗、Tafel极化曲线以及J-V曲线进行表征。研究结果表明,FTO/CoS/CuS对电极与电解液界面处的电荷转移阻抗较低,具有更高的光反射率及电催化活性。与Au片、FTO/CoS和FTO/CuS对电极相比,光电转化效率分别提高了132.9%,46.6%,26.9%。     

Dye‐affinity hollow‐fibres and their lysozyme adsorption–desorption characteristics

Dye‐affinity adsorption is increasingly used for protein separation. Hollow‐fibres have advantages as adsorbents in comparison to conventional bead supports because they are not compressible and can eliminate internal diffusion limitations. The aim of this study was to explore in detail the performance of polyamide hollow‐fibres to which Reactive Green HE‐4BD was attached for adsorption of lysozyme. The hollow‐fibre was characterized by scanning electron microscopy. These dye‐carrying hollow‐fibres (26.3 µmol g^?1) were used in the lysozyme adsorption–elution studies. The effect of initial concentration of lysozyme and medium pH on the adsorption efficiency of dye‐attached hollow‐fibres was studied in a batch system. The non‐specific adsorption of lysozyme on the polyamide hollow‐fibres was 1.8 mg g^?1. Reactive Green HE‐4BD attachment significantly increased the lysozyme adsorption up to 41.1 mg g^?1. Langmuir adsorption model was found to be applicable in interpreting lead adsorption by Reactive Green HE‐4BD attached hollow fibres. Significant amount of the adsorbed lysozyme (up to 95%) was eluted in 1 h in the elution medium containing 1.0 M NaSCN at pH 8.0. In order to determine the effects of adsorption conditions on possible conformational changes of lysozyme structure, fluorescence spectrophotometry was employed. We concluded that polyamide dye‐affinity hollow‐fibres can be applied for lysozyme adsorption without causing any significant conformational changes. Repeated adsorption–elution processes showed that these dye‐attached hollow‐fibres are suitable for lysozyme adsorption. © 2001 Society of Chemical Industry     

Composites of Ultrahigh‐Molecular‐Weight Polyethylene with Graphene Sheets and/or MWCNTs with Segregated Network Structure: Preparation and Properties

UHMWPE/MWCNT and UHMWPE/GNS composites with a segregated network are prepared. TEM and SEM images indicate that the conducting fillers are distributed on the UHMWPE surface and form a segregated conducting network. The percolation threshold of UHMWPE/GNS composites is ≈0.25 wt% and that of UHMWPE/MWCNT composites is 0.20 wt%. The electrical conductivity of UHMWPE/GNS composites is almost four orders of magnitude lower than that of the UHMWPE/MWCNT composites. For equivalent concentrations of GNS and MWCNT, the composites with hybrid fillers exhibit a lower percolation threshold and a higher conductivity than that with GNS or MWCNT alone. Due to the high strength of the fillers and the segregated network structure, the mechanical properties of the composites first increase and then decrease with increasing filler content.

     

Ionic liquid/poly(ionic liquid)‐based electrolytes for energy devices

Ionic liquids are organic salts with melting points generally below 100 °C. They are attracting wide attention and are used as electrolytes in electrochemical devices, such as fuel cells, lithium‐ion batteries, dye‐sensitized solar cells, supercapacitors and light‐emitting electrochemical cells, due to their negligible vapor pressure, high ionic conductivity and wide electrochemical window. This perspective article highlights the applications of ionic liquid‐ or poly(ionic liquid)‐based electrolytes in fuel cells, dye‐sensitized solar cells and supercapacitors. © 2013 Society of Chemical Industry     

Synergetic effect of graphene sheet and three‐dimensional crumpled graphene on the performance of dye‐sensitized solar cells

Herein, an improved structure of the dye‐sensitized solar cell (DSSC) is demonstrated which is composed of surface modified fluorine‐doped tin oxide (FTO) glass with graphene (GR) sheets and TiO₂ films incorporated with three‐dimensional crumped graphene (3‐D CGR)/GR sheets. The morphologies of the as‐prepared GR sheets on FTO glasses and 3‐D CGR/GR sheets/TiO₂ films were observed by field‐emission scanning electron microscopy. Light harvesting and charge recombination kinetics were investigated with a solar simulator and electrochemical impedance spectroscopy analysis. In addition to the reduced charge resistance by the GR modified FTO, the enhanced dye loading capability of the 3‐D CGR, and the rapid charge transport by the 2‐D GR sheets, the power conversion efficiency was 7.2%, which was an increase of 56% compared to a “conventional” structured DSSC. © 2015 American Institute of Chemical Engineers AIChE J, 62: 574–579, 2016