Oligomer ethylene glycol based electrolytes for dye‐sensitized solar cell

Oligomer ethylene glycol (O‐EG) based electrolytes without volatile components were prepared and used in dye‐sensitized solar cell (DSSC). The characteristics such as viscosity, ionic conductivity, and ionic activation energy of O‐EG based electrolytes including liquid, gel and solid states were investigated and compared. It is found that the gel and solid O‐EG electrolytes have two E_a values with the changed phase state by going with the increased temperature, and they can increase the onset of applied voltage for generating dark current in DSSCs as from 0.222 V with liquid O‐EG electrolyte to 0.420 V with gel and solid O‐EG electrolytes, which results in the enhanced light‐to‐electricity conversion efficiency from 1.4% with liquid to 1.82% with gel and 1.86% with solid electrolytes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Novel microporous poly(vinylidene fluoride)‐graft‐poly(tert‐butyl acrylate) electrolytes for secondary lithium batteries

BACKGROUND: Much interest has recently been shown in improving the performance of lithium‐ion polymer batteries with gel polymer electrolytes (GPEs) due to a rapid expansion in industrial demand. Novel GPEs based on poly(vinylidene fluoride)‐graft‐poly(tert‐butyl acrylate) (PVDF‐g‐tBA) microporous mats are suggested in this study. RESULTS: Microfibrous polymer electrolytes were prepared using electrospinning and characterized for extent of grafting, morphology, crystallinity, electrochemical stability, ionic conductivity, interfacial resistance and cell cycleability. The degree of crystallinity was lower for tBA‐grafted PVDF mats than that of neat PVDF. The PVDF‐g‐tBA showed an improvement in the ionic conductivity, electrochemical stability, interfacial resistance and cyclic performance. CONCLUSION: The tBA‐grafted PVDF microporous electrolytes are promising candidates for enhancing the performance of lithium‐ion polymer batteries. Copyright © 2008 Society of Chemical Industry     

Preparation and properties of cross‐linked poly(ethylene glycol)/poly[(vinylidene fluoride)‐co‐hexafluoropropylene] interpenetrating network‐type electrolytes for secondary lithium batteries

Cross‐linked poly(ethylene glycol)/poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (XPEG/PVDF–HFP) gel‐type polymer electrolyte interpenetrating polymer networks (IPNs) were prepared by cross‐linking the PEG molecules in the presence of PVDF–HFP molecules. Thermal, mechanical, swelling and electrochemical properties, as well as microstructures of the prepared polymer electrolytes, were investigated for various polymer compositions. The mechanical strength increased, but the swelling ratio in electrolyte solution decreased with increasing PVDF–HFP content. The ion conductivity was highly affected by the type of electrolyte salt, and increased with increasing XPEG concentration. The Arrhenius‐type relationship was observed in the temperature dependence of ion conductivity. The polymer electrolyte systems prepared in this study were electrochemically stable up to about 5 V. Copyright © 2005 Society of Chemical Industry     

Synthesis and gelation of fluoroalkyl end‐capped copolymers containing glucosyl segments: Application to new fluorinated conductive polymer electrolytes

Fluoroalkyl end‐capped copolymers containing glucosyl segments were prepared by the copolymerizations of fluoroalkanoyl peroxides with 2‐glucosyoxyethyl methacrylate (GEMA) and comonomers such as acrylic acid (ACA) and methacrylate monomer‐containing poly(oxyethylene) units (PME). Under the non‐cross‐linked conditions, fluoroalkyl end‐capped GEMA–ACA and GEMA–PME copolymers were found to cause a gelation in dimethyl sulfoxide (DMSO), where the aggregations of end‐capped fluoroalkyl segments and the hydrogen‐bonding interaction between hydroxyl segments are involved in establishing a physical gel network, although the corresponding nonfluorinated GEMA copolymers could cause no gelation in DMSO. More interestingly, it was demonstrated that these fluorinated polymeric gelling electrolytes containing lithium salts exhibit a considerably high ionic conductivity of 10^?3 S/cm level at room temperature. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2833–2838, 2002     

Application of polymer gel electrolyte with graphite powder in quasi‐solid‐state dye‐sensitized solar cells

A polymer gel electrolyte with ionic conductivity of 5.11 mS cm⁻¹ was prepared by using poly (acrylonitrile‐co‐styrene) as polymer matrix, acetonitrile and tetrahydrofuran as binary organic mixture solvent, NaI + I₂ as electrolyte, graphite powder and 1‐methylimidazole as additives. The components ratio of the polymer gel electrolyte was optimized, and the influence of the components and temperature on the ionic conductivity of the polymer gel electrolyte and photoelectronic properties of dye sensitized solar cell were investigated. On the basis of the polymer gel electrolyte with the optimized conditions, a quasi‐solid‐state dye‐sensitized solar cell was fabricated and its light‐ to‐electricity energy conversion efficiency of 3.25% was achieved under irradiation of 100 mW cm⁻². POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Preparation of narrow‐disperse or monodisperse poly{[poly(ethylene glycol) methyl ether acrylate]‐co‐(acrylic acid)} microspheres with ethyleneglycol dimethacrylate as crosslinker by distillation precipitation polymerization

Narrow‐disperse or monodisperse poly{[poly(ethylene glycol) methyl ether acrylate]‐co‐(acrylic acid)} (poly(PEGMA‐co‐AA)) microspheres were prepared by distillation precipitation polymerization with ethyleneglycol dimethacrylate (EGDMA) as crosslinker with 2,2′‐azobisisobutyronitrile as initiator in neat acetonitrile in the absence of any stabilizer, without stirring. The diameters of the resultant poly(PEGMA‐co‐AA‐co‐EGDMA) microspheres were in the range 200–700 nm with a polydispersity index of 1.01–1.14, which depended on the comonomer feed of the polymerization. The addition of the hydrogen bonding monomer acrylic acid played an essential role in the formation of narrow‐disperse or monodisperse polymer microspheres during the polymerization. Copyright © 2006 Society of Chemical Industry     

Bifunctional poly(ethylene glycol) based crosslinked network polymers as electrolytes for all‐solid‐state lithium ion batteries

Polymer electrolyte based lithium ion batteries represent a revolution in the battery community due to their intrinsic enhanced safety, and as a result polymer electrolytes have been proposed as a replacement for conventional liquid electrolytes. Herein, the preparation of a family of crosslinked network polymers as electrolytes via the ‘click‐chemistry’ technique involving thiol‐ene or thiol‐epoxy is reported. These network polymer electrolytes comprise bifunctional poly(ethylene glycol) as the lithium ion solvating polymer, pentaerythritol tetrakis (3‐mercaptopropionate) as the crosslinker and lithium bis(trifluoromethane)sulfonimide as the lithium salt. The crosslinked network polymer electrolytes obtained show low T_g, high ionic conductivity and a good lithium ion transference number (ca 0.56). In addition, the membrane demonstrated sterling mechanical robustness and high thermal stability. The advantages of the network polymer electrolytes in this study are their harmonious characteristics as solid electrolytes and the potential adaptability to improve performance by combining with inorganic fillers, ionic liquids or other materials. In addition, the simple formation of the network structures without high temperatures or light irradiation has enabled the practical large‐area fabrication and in situ fabrication on cathode electrodes. As a preliminary study, the prepared crosslinked network polymer materials were used as solid electrolytes in the elaboration of all‐solid‐state lithium metal battery prototypes with moderate charge–discharge profiles at different current densities leaving a good platform for further improvement. © 2018 Society of Chemical Industry     

Preparation of poly(divinylbenzene‐co‐N‐isopropylacrylamide) microspheres and their hydrogen‐bonding assembly behavior for raspberry‐like core‐corona polymer composite

Narrowdisperse poly(divinylbenzene‐co‐N‐isopropylacrylamide) (poly(DVB‐co‐NIPAM)) functional microspheres with the diameter in the range of 630 nm and 2.58 μm were prepared by distillation–precipitation polymerization in neat acetonitrile in the absence of any stabilizer. The effect of N‐isopropylacrylamide (NIPAM) ratio in the comonomer feed on the morphology of the resultant polymer particles was investigated in detail with divinylbenzene (DVB) as crosslinker and 2,2′‐azobisisobutyronitrile (AIBN) as initiator. The monodisperse poly(DVB‐co‐NIPAM) microspheres with NIPAM fraction of 20 wt % were selected for the preparation of raspberry‐like core‐corona polymer composite by the hydrogen‐bonding self‐assembly heterocoagulation with poly(ethyleneglycol dimethacrylate‐co‐acrylic acid) [poly(EGDMA‐co‐AA)] nanospheres. Both of the functional poly(DVB‐co‐NIPAM) microspheres and the core‐corona particles were characterized with scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), and elemental analysis (EA). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1350–1357, 2007     

Synthesis and characterization of poly(urethane‐co‐imidine)s having pendent phenyl and benzylidene groups using bisphthalides,bislactones and blocked polyurethane prepolymers

Poly(urethane‐co‐imidine)s were prepared using amine blocked polyurethane (PU) prepolymer. The PU prepolymer was prepared by the reaction of poly(propylene glycol) (PPG₂₀₀₀) and 2,4‐tolylene diisocyanate (TDI) and end capped with N‐methyl aniline. The PU prepolymer was then reacted with bisphthalides and bislactones, until the evolution of carbon dioxide ceased. Polymerization reactions with bispthalides and bislactone took more time than with dianhydrides. Polymers were characterized by FTIR, GPC, TG and DSC analyses. Molecular weights of the poly(urethane‐co‐imidine)s were found to be lower than that of poly(urethane‐co‐imide)s. Compared to poly(urethane‐co‐imide)s all poly(urethane‐co‐imidine)s showed high glass transition temperature and crystallization peak in DSC. The thermal stability of the polyurethanes was found to increase with the introduction of imidine component. © 2001 Society of Chemical Industry     

Preparation of hairy particles by grafting PEG onto the poly(styrene‐co‐maleic anhydride) surface and PEG effect on SiO2 nanoparticles adsorption

Hairy particles were prepared by immobilization of poly(ethylene glycol) (PEG) on the surface of poly(styrene‐co‐maleic anhydride) (poly(S‐co‐MA)) spheres. It was found that the carbonyl groups on the poly(S‐co‐MA) surface can be conveniently esterified with the hydroxyl groups of PEG. Chemical and morphological changes were analyzed by FT‐IR, TEM, and water contact angle. Results revealed that, with the immobilization of PEG, the morphology of poly(S‐co‐MA) turned from a smooth surface to a hairy‐like structure and the hydrophilicity of the polymer particles improved. In addition, berry‐like polymer/silica particles can be obtained by using the hairy particles as template. The PEG hairy chains show steric repulsion during the deposition of silica nanoparticles by in situ sol‐gel process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Poly(urethane acrylate)‐based gel polymer films for mechanically stable,transparent, and highly conductive polymer electrolyte applications

Polymer electrolytes are attractive for the applications in conventional electrochemical devices and emerging flexible devices. In this study, we developed a poly(urethane acrylate)‐based gel polymer electrolyte with excellent mechanical stability, optical transparency, and a high ionic conductivity. These polymer electrolytes showed excellent dimensional stability and an elastomer‐like behavior with a Shore A hardness in the range of 20–40. The optical transmittance values of these polymers films were over 80% in the visible range. Their ionic conductivities were controlled via changes in the concentration of the linker, dimethylol propionic acid (DMPA), and the lithium salt incorporated into the polymer. The maximum ionic conductivity reached 3.7 mS/cm at room temperature (～23 °C) when the DMPA/poly(ethylene glycol) molar ratio was 0.25, and the ionic conductivity was found to be proportional to the salt concentration. We believe that these polymer electrolytes will be useful in various electrochemical applications where flexibility, high ionic conductivity, and transparency in the electrolytes are necessary. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45009.     

Synthesis and micellization behavior of amphiphilic graft copolymer with 1‐octene as hydrophobic moiety

Two new kinds of amphiphilic copolymers were synthesized in this work. Poly(1‐octene‐co‐acrylic acid) copolymers were prepared through the copolymerization of 1‐octene and tert‐butyl acrylate, and the hydrolysis of tert‐butyl acrylate units. Poly(1‐octene‐co‐acrylic acid)‐g‐poly (ethylene glycol) copolymers were obtained from the esterification reaction between poly(1‐octene‐co‐acrylic acid) and poly(ethylene glycol) monomethyl ether. They were characterized by means of ¹H‐NMR, ¹³C‐NMR, GPC, and FTIR. These amphiphilic copolymers can form stable micelles in aqueous solutions. The critical micelle concentration was determined by fluorescence spectroscopy. The micellar morphology and size distribution were investigated by transmission electron microscopy and dynamic light scattering. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Hydroxyethyl chitosan‐g‐poly(acrylic acid‐co‐sodium acrylate) superabsorbent polymers

A novel hydroxyethyl chitosan‐g‐poly(acrylic acid‐co‐Sodium Acrylate) (HECTS‐g‐(PAA‐co‐PSA)) superabsorbent polymer was prepared through graft copolymerization of acrylic acid and sodium acrylate onto the chain of hydroxyethyl chitosan. The structure of the polymer was characterized by FTIR. By studying the water absorption of the polymer synthesized under different conditions, the optimal conditions for synthesizing the polymer with the highest swelling ratio was defined. This superabsorbent polymer was further treated by the solvent precipitation method and by the freeze‐drying method. We found that the water absorption rate of the treated polymer was greatly increased and the microstructure of the treated polymer was changed from small pores to loose macro pores. The swelling processes of the polymers before and after modification fit first‐order dynamic processes. The amount of the residual acrylic acid was greatly decreased after treatments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Electrochemical studies on composite gel polymer electrolytes for lithium sulfur‐batteries

Poly(ethylene oxide)‐based composite gel polymer electrolytes (CGPE's) were prepared for various concentrations of magnesium aluminate (MgAl₂O₄) and LiTFSI as salt with a combination of 1,3‐dioxolane (DOL) and tetraethylene glycol dimethyl ether (TEGDME) as plasticizer by a simple solution casting technique. The addition of plasticizers has significantly improved the ionic conductivity of the gel electrolytes. The prepared CGPEs were subjected to scanning electron microscopy, thermal, and FT‐IR analysis. The electrochemical properties such as ionic conductivity, compatibility, and charge–discharge behavior have also been studied. Preliminary studies revealed that the prepared CGPE can be employed as a potential electrolyte for lithium–sulfur (Li–S) batteries. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44594.     

Synthesis and characterization of biodegradable block copolymers of poly(propylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) and poly(ethylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol)

The synthesis of two low molecular weight linear unsaturated oligoester precursors, poly(propylene fumarate‐co‐sebacate) (PPFS) and poly(ethylene fumarate‐co‐sebacate) (PEFS), are described. PPFS, PEFS, and poly(ethylene glycol) are then used to prepare poly(propylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PPFS‐co‐PEG) and poly(ethylene fumarate‐co‐sebacate)‐co‐poly(ethylene glycol) (PEFS‐co‐PEG) block copolymers. The products thus obtained are investigated in terms of the molecular weight, composition, structure, thermal properties, and solubility behavior. A number of design parameters including the molecular weights of PPFS, PEFS, and PEG, the reaction time in the polymer synthesis, and the weight ratio of PEG to PPFS or to PEFS are varied to assess their effects on the product yield and properties. The hydrolytic degradation of PPFS‐co‐PEG and PEFS‐co‐PEG in an isotonic buffer (pH 7.4, 37°C) is investigated, and it is found that the fumarate ester bond cleaves faster than does the sebacate ester bond. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 295–300, 2004     

Electrical properties of sorbitol‐doped poly(vinyl alcohol)–poly(acrylamide‐co‐acrylic acid) polymer membranes

Solid polymer membranes from poly(vinyl alcohol) (PVA) and poly(acrylamide‐co‐acrylic acid) (PAA) with varying doping ratios of sorbitol were prepared using the solution casting method. The films were examined with Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and AC impedance spectroscopy. The impedance measurements showed that the ionic conductivity of PVA–PAA polymer membrane can be controlled by controlled doping of sorbitol within the polymer blends. The PVA–PAA–sorbitol membranes were found to exhibit excellent thermal properties and were stable for a wide temperature range (398–563K), which creates a possibility of using them as suitable polymers for device applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of novel core‐shell magnetic nanogels based on 2‐acrylamido‐2‐methylpropane sulfonic acid in aqueous media

Ultrafine well‐dispersed Fe₃O₄ magnetic nanoparticles were directly prepared in aqueous solution using controlled coprecipitation method. The synthesis of Fe₃O₄/poly (2‐acrylamido‐2‐methylpropane sulfonic acid) (PAMPS), Fe₃O₄/poly (acrylamide‐co‐2‐acrylamido‐2‐methylpropane sulfonic acid) poly(AM‐co‐AMPS) and Fe₃O₄/poly (acrylic acid‐co‐2‐acrylamido‐2‐methylpropane sulfonic acid) poly(AA‐co‐AMPS) ‐core/shell nanogels are reported. The nanogels were prepared via crosslinking copolymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid, acrylamide and acrylic acid monomers in the presence of Fe₃O₄ nanoparticles, N,N′‐methylenebisacrylamide (MBA) as a crosslinker, N,N,N′,N′‐tetramethylethylenediamine (TEMED) and potassium peroxydisulfate (KPS) as redox initiator system. The results of FTIR and ¹H‐NMR spectra indicated that the compositions of the prepared nanogels are consistent with the designed structure. X‐ray powder diffraction (XRD) and transmission electron microscope (TEM) measurements were used to determine the size of both magnetite and stabilized polymer coated magnetite nanoparticles. The data showed that the mean particle size of synthesized magnetite (Fe₃O₄) nanoparticles was about 10 nm. The diameter of the stabilized polymer coated Fe₃O₄ nanogels ranged from 50 to 250 nm based on polymer type. TEM micrographs proved that nanogels possess the spherical morphology before and after swelling. These nanogels exhibited pH‐induced phase transition due to protonation of AMPS copolymer chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polymer nanocomposites containing carbon nanotubes and miscible polymer blends based on poly[ethylene‐co‐(acrylic acid)]

Four binary polymer blends containing poly [ethylene‐co‐(acrylic acid)] (PEAA) as one component, and poly(4‐vinyl phenol‐co‐2‐hydroxy ethyl methacrylate) (P4VPh‐co‐2HEMA) or poly(2‐ethyl‐2‐oxazoline) (PEOx) or poly(vinyl acetate‐co‐vinyl alcohol) (PVAc‐co‐VA) or poly (vinylpyrrolidone‐co‐vinyl acetate) (PVP‐co‐VAc) as the other component were prepared and used as a matrix of a series of composite materials. These binary mixtures were either partially or completely miscible within the composition range studied and were characterized by differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (FTIR). Carbon nanotubes (CNTs) were prepared by a thermal treatment of polyester synthesized through the chemical reaction between ethylene glycol and citric acid over an alumina boat. High resolution transmission electron microscopy (HRTEM) was used to characterize the synthesized CNTs. Films of composite materials containing CNTs were obtained after evaporation of the solvent used to prepare solutions of the four types of binary polymer blends. Young's moduli of the composites were obtained by thermomechanical analysis at room temperature. Only one glass transition temperature was detected for several compositions on both binary blends and the composite material matrices. Evidence of hydrogen bond formation was recorded for both miscible blends and composite materials. The degree of crystallinity and Young's moduli of the CNT‐polymer composites increased compared to the single polymer blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Design of highly stretchable deep eutectic solvent-based ionic gel electrolyte with high ionic conductivity by the addition of zwitterion ion dissociators for flexible supercapacitor

Nonvolatile deep eutectic solvent (DES) electrolytes with good electrochemical stability have recently emerged as promising electrolytes for energy storage devices. In this report, for the first time a polymerized zwitterionic molecule was introduced and a series of hybrid cross-linked zwitterion-containing copolymer DES gels are synthesized via UV initiated free-radical copolymerization of acrylic acid (AA), sulfobetaine vinylimidazole (VIPS) and poly(ethylene glycol) diacrylate (PEGDA) monomers, in situ within DES, which is prepared from 1:2 M ratio of choline chloride and ethylene glycol. Systematically varying the AA:VIPS molar ratio and copolymer contents within the copolymer network enables one to widely tune the mechanical properties and ionic conductivity of the poly(AA-co-VIPS) DES gels. The tensile strength of P(AA-co-VIPS) DES gels significantly increased from 28 kPa to 176 kPa with fracture strain from 720% to 1370%, while the ionic conductivity of copolymer DES gels remains high from 2.7 to 4.1 mS cm⁻¹ with the increase of copolymer content from 25 wt % to 45 wt%. A copolymer DES gel not only enables a supercapacitor deliver high capacitance of 71.52 F g⁻¹ at 0.5 A g⁻¹, and retains ∼97% of its capacitance after 2000 cycles, but also achieves outstanding capacitive performance over wide temperature range.     

Ionic conductivity and morphology of semi‐interpenetrating‐type polymer electrolyte entrapping poly(siloxane‐g‐allyl cyanide)

We prepared a semi‐IPN (interpenetrating network)‐type solid polymer electrolyte (SPE) using poly (ethylene glycol)dimethacrylate (PEGDMA) as a polymer matrix containing a monocomb‐type poly(siloxane‐g‐allyl cyanide) and poly(ethylene glycol)dimethylether (PEGDME) for the lithium secondary battery. The poly(siloxane‐g‐allyl cyanide)s were prepared by a hydrosilation reaction of poly (methyl hydrosiloxane) with allyl cyanide and characterized by ¹H NMR and FTIR. The semi‐IPN‐type electrolyte was prepared by thermal curing, and conductivities of samples were measured by impedance spectroscopy using an indium tin oxide (ITO) electrode. The ionic conductivity of the semi‐IPN‐polymer electrolyte was about 1.05 × 10^?5 S cm^?1 with 60 wt % of the poly(siloxane‐g‐allyl cyanide) and 6.96 × 10^?4 S cm^?1 with 50 wt % of the PEGDME and 10 wt % of the poly(siloxane‐g‐allyl cyanide) at 30°C. The SEM morphology of the cross section of the semi‐IPN‐polymer electrolyte film was changed from discontinuous network to continuous network as increasing the PEGDME content and decreasing the poly(siloxane‐g‐allyl cyanide) content. The mechanical stability was also enhanced when increasing the PEGDME content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008