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1.
We prepared two block copolymers 1 and 2 consisting of a third‐generation dendron with poly(ethylene oxide) (PEO) peripheries and a linear polystyrene (PS) coil. The PS molecular weights were 2000 g/mol and 8000 g/mol for 1 and 2 , respectively. The differential scanning calorimetry (DSC) data indicated that neither of the block copolymers showed glass transition, implying that there was no microphase separation between the PEO and PS blocks. However, upon doping the block copolymers with lithium triflate (lithium concentration per ethylene oxide unit = 0.2), two distinct glass transitions were seen, corresponding to the salt‐doped PEO and PS blocks, respectively. The morphological analysis using small angle X‐ray scattering (SAXS) and transmission electron microscopy (TEM) demonstrated that a hexagonal columnar morphology was induced in salt‐doped sample 1‐Li+ , whereas the other sample ( 2‐Li+ ) with a longer PS coil revealed a lamellar structure. In particular, in the SAXS data of 2‐Li+ , an abrupt reduction in the lamellar thickness was observed near the PS glass transition temperature (Tg), in contrast to the SAXS data for 1‐Li+ . This reduction implies that there is a lateral expansion of the molecular section in the lamellar structure, which can be interpreted by the conformational energy stabilization of the long PS coil above Tg. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2372–2376, 2010  相似文献   

2.
Mixed micelles of polystyrene‐b‐poly(N‐isopropylacrylamide) (PS‐b‐PNIPAM) and two polystyrene‐b‐poly(ethylene oxide) diblock copolymers (PS‐b‐PEO) with different chain lengths of polystyrene in aqueous solution were prepared by adding the tetrahydrofuran solutions dropwise into an excess of water. The formation and stabilization of the resultant mixed micelles were characterized by using a combination of static and dynamic light scattering. Increasing the initial concentration of PS‐b‐PEO in THF led to a decrease in the size and the weight average molar mass (〈Mw〉) of the mixed micelles when the initial concentration of PS‐b‐ PNIPAM was kept as 1 × 10?3 g/mL. The PS‐b‐PEO with shorter PS block has a more pronounced effect on the change of the size and 〈Mw〉 than that with longer PS block. The number of PS‐b‐PNIPAM in each mixed micelle decreased with the addition of PS‐b‐PEO. The average hydrodynamic radius 〈Rh〉 and average radius of gyration 〈Rg〉 of pure PS‐b‐PNIPAM and mixed micelles gradually decreased with the increase in the temperature. Both the pure micelles and mixed micelles were stable in the temperature range of 18 °C–39 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1168–1174, 2010  相似文献   

3.
Poly(siloxane‐urethane‐urea) elastomers containing both polysiloxane and polyethylene oxide (PEO) segments in the polymer chain were obtained by moisture‐curing of NCO‐terminated poly(siloxane‐urethane) prepolymers synthesized from isophorone diisocyanate and mixtures of polyoxyethylene diols and polysiloxane diols with various molecular weights. Mechanical properties of the moisture‐cured films and their swelling ability in solvent mixtures commonly used in lithium batteries were investigated, and it was found that they were greatly influenced by PEO content in the polymer. PEO content in the polymer was also found to affect very much the electric conductivity of the films after immersion in lithium salt solution in ethylene carbonate–dimethyl carbonate solvent mixture. At high contents of PEO in the polymer chain specific conductivities of the films in a range of 10?3, Scm?1 could be achieved at room temperature. Based on the results of Scanning Electron Microscopy with X‐ray Analysis (SEM/EDS) investigations and wide‐angle X‐ray scattering and small‐angle X‐ray scattering studies, it could be anticipated that the reason for good conductivity of the films might be their specific supramolecular structure that potentially facilitated lithium ion mobility. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

4.
Using sequential RAFT polymerization, single monomer insertion, and “click” chemistry, a series of triblock copolymers, poly(ethylene oxide)‐b‐polystyrene‐b‐poly(ethylene oxide), PEO‐b‐PS‐b‐PEO, were synthesized, where one of the two junction points is a UV cleavable ortho‐nitrobenzyl (ONB). Ordered patterns of PEO‐b‐PS‐b‐PEO were produced by solvent vapor annealing. Upon exposure to ultraviolet (UV) light, the PEO‐b‐PS‐b‐PEO was converted into a mixture of a PEO homopolymer and a PS‐b‐PEO diblock copolymer. It was found that the microdomain spacing could be tuned by adjusting the UV exposure time, due to the change in the copolymer architecture and the swelling of the PEO microdomain by the PEO homopolymer produced. By selective area exposure of the PEO‐b‐PS‐b‐PEO thin films, the domain spacing was changed over selected locations across the film, generating patterns of different microdomain sizes. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 355–361.  相似文献   

5.
High molecular weight polystyrene‐block‐poly(ethylene oxide) diblock copolymer (PS‐b‐PEO) is utilized as colloidal spheres in the presence of water. Adequately thick films with multilayers of spherical macropores are fabricated in one‐pot under highly concentrated conditions of PS‐b‐PEO. The frameworks are constructed using aluminum organophosphonate as a complicated hybrid component. The macropores (30–200 nm) are homogeneously distributed over the entire films and pore windows between the macropores are tunable (up to nearly 10 nm) by changing the relative amount of PS‐b‐PEO in the precursor solutions.  相似文献   

6.
A series of well‐defined ABC 3‐Miktoarm star‐shaped terpolymers [Poly(styrene)‐Poly(ethylene oxide)‐Poly(ε‐caprolactone)](PS‐PEO‐PCL) with different molecular weight was synthesized by combination of the “living” anionic polymerization with the ring‐opening polymerization (ROP) using macro‐initiator strategy. Firstly, the “living” poly(styryl)lithium (PS?Li+) species were capped by 1‐ethoxyethyl glycidyl ether(EEGE) quantitatively and the PS‐EEGE with an active and an ethoxyethyl‐protected hydroxyl group at the same end was obtained. Then, using PS‐EEGE and diphenylmethylpotassium (DPMK) as coinitiator, the diblock copolymers of (PS‐b‐PEO)p with the ethoxyethyl‐protected hydroxyl group at the junction point were achieved by the ROP of EO and the subsequent termination with bromoethane. The diblock copolymers of (PS‐b‐PEO)d with the active hydroxyl group at the junction point were recovered via the cleavage of ethoxyethyl group on (PS‐b‐PEO)p by acidolysis and saponification successively. Finally, the copolymers (PS‐b‐PEO)d served as the macro‐initiator for ROP of ε‐CL in the presence of tin(II)‐bis(2‐ethylhexanoate)(Sn(Oct)2) and the star(PS‐PEO‐PCL) terpolymers were obtained. The target terpolymers and the intermediates were well characterized by 1H‐NMR, MALDI‐TOF MS, FTIR, and SEC. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1136–1150, 2008  相似文献   

7.
In order to investigate the relationship between ionic conductivity and liquid crystallinity, we prepared the main‐chain type polyester having 1,4‐bisstyrylbenzene units and ethyleneoxide chain in the repeating unit. The main‐chain type polyester with lithium salt at the ratio of 0.04 per polymer repeating unit exhibited a smectic phase. However, the polyester with lithium salt (0.11) showed a nematic phase. The ionic conductivity of the polyester with lithium salt increased with increasing lithium salt concentration. The trans‐type polyester exhibited a liquid crystalline phase, while the cis‐type polyester did not show any mesophase. We found that the ionic conductivity of the trans‐type polyester with lithium salt (0.11) was larger than that of the cis‐type polyester with lithium salt (0.11). However, a liquid crystalline phase was found in the side‐chain type polyether with alkoxy chain length of below 12. A smectic phase was induced for the non‐mesomorphic polyethers with lithium salt. The layer spacing of the smectic A phase for the non‐mesomorphic polyether with lithium salt decreased from 55 to 41 Å with increasing temperature. The ionic conductivity of the polyether with lithium salt increased with decreasing the layer spacing. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

8.
Mesoporous alumina films with large‐sized cage‐type mesopores were prepared by using commercially available diblock copolymer (PS‐b‐PEO) and economic inorganic salt (AlCl3) as aluminum source. The obtained mesopore sizes drastically expand from 35 nm to 80 nm when the amount of ethanol in the precursor solutions were controlled. More interestingly, under an optimized amount of ethanol as co‐solvent, there was no significant change of micelle morphology on the substrate, even though the relative amount of PS‐b‐PEO to alumina source was dramatically varied. When the amount of alumina precursor was decreased, the pore walls gradually became thinner, thereby improving pore connectivity. The ordered mesoporous alumina films obtained in this study exhibit high thermal stability up to 1000 °C, and their frameworks are successfully crystallized to γ‐alumina phase. This technique could also be applicable for creating other metal oxide thin films with large mesopores.  相似文献   

9.
Well‐defined ABCD 4‐Miktoarm star‐shaped quarterpolymers of [poly(styrene)‐poly(tert‐butyl acrylate)‐poly(ethylene oxide)‐poly(isoprene)] [star(PS‐PtBA‐PEO‐PI)] were successfully synthesized by the combination of the “click” chemistry and multiple polymerization mechanism. First, the poly(styryl)lithium (PS?Li+) and the poly(isoprene)lithium (PI?Li+) were capped by ethoxyethyl glycidyl ether (EEGE) to form the PS and PI with both an active ω‐hydroxyl group and an ω′‐ethoxyethyl‐protected hydroxyl group, respectively. After these two hydroxyl groups were selectively modified to propargyl and 2‐bromoisobutyryl group for PS, the resulted PS was used as macroinitiator for ATRP of tBA monomer and the diblock copolymer PS‐b‐PtBA with a propargyl group at the junction point was achieved. Then, using the functionalized PI as macroinitiator for ROP of EO monomer and bromoethane as blocking agent, the diblock copolymer PI‐b‐PEO with a protected hydroxyl group at the conjunction point was synthesized. After the hydrolysis, the recovered hydroxyl group of PI‐b‐PEO was modified to bromoacetyl and then azide group successively. Finally, the “click” chemistry between them was proceeded smoothly. The obtained star‐shaped quarterpolymers and intermediates were characterized by 1H NMR, FT‐IR, and SEC in detail. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2154–2166, 2008  相似文献   

10.
A well‐defined (PEO‐PS)2‐PLA miktoarm terpolymer ( 1 ) was synthesized by stepwise click reactions of individually prepared poly(ethylene oxide) (PEO), polystyrene (PS, polymerized by atom transfer radical polymerization), and polylactide (PLA, polymerized by ring‐opening polymerization) blocks. As characterized by differential scanning calorimetry and small‐angle X‐ray scattering techniques, the terpolymer self‐assembled into a hexagonal columnar structure consisting of PLA/PEO cylindrical cores surrounded by PS chains. In contrast, the ion‐doped sample ( 1‐Li+ ) with lithium concentration per ethylene oxide = 0.2 exhibited a three‐phase lamellar structure, which was attributed to the microphase separation between PEO and PLA blocks and to the conformational stabilization of the longest PLA chain. The two‐phase columnar morphology before the ion doping was used to prepare a nanoporous material. PLA chains in the cylindrical core region were hydrolyzed by sodium hydroxide, producing nanopores with a pore diameter of about 14 nm. The resulted nanoporous material sank to the bottom in water, because of water‐compatible PEO chains on the walls. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013  相似文献   

11.
The thermodynamic properties of triblock copolymer of polystyrene–poly (ethylene oxide)–polystyrene (PS‐b‐PEO‐b‐PS) were investigated by means of inverse gas chromatography (IGC) using 15 different kinds of solvents as the probes. Some thermodynamic parameters, such as specific retention volume, molar heats of sorption, weight fraction activity coefficient, Flory‐Huggins interaction parameter, partial molar heats of mixing and solubility parameter were obtained to judge the interactions between PS‐b‐PEO‐b‐PS polymers and solvents and the solubility of the polymers in these solvents. It was found that increasing PEO content in PS‐b‐PEO‐b‐PS resulted in the increase in the solubility of PS‐b‐PEO‐b‐PS in alkanes and acetates solvents, but the solubility in alcohols had no change, and more PEO content in polymer caused a small decrease in the solubility parameter of PS‐b‐PEO‐b‐PS polymer, © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2015–2022, 2007  相似文献   

12.
The amphiphilic cyclic poly(ethylene oxide)‐block‐polystyrene [c‐(PEO‐b‐PS)] was synthesized by cyclization of propargyl‐telechelic poly(ethylene oxide)‐block‐polystyrene‐block‐poly(ethylene oxide) (?? PEO‐b‐PS‐b‐PEO? ?) via the Glaser coupling. The hydroxyl‐telechelic ABA triblock PEO‐b‐PS‐b‐PEO was first prepared by successive living anionic polymerization of styrene and ring‐opening polymerization of ethylene oxide, and then the hydroxyl ends were reacted with propargyl bromide to obtain linear precursors with propargyl terminals. Finally, the intramolecular cyclization was conducted in pyridine under high dilution by Glaser coupling of propargyl ends in the presence of CuBr under ambient temperature, and the c‐(PEO‐b‐PS) was directly obtained by precipitation in petroleum ether with high efficiency. The cyclic products and their corresponding linear precursor ?? PEO‐b‐PS‐b‐PEO? ? were characterized by means of GPC, 1H NMR, and FTIR. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011  相似文献   

13.
With anodic aluminum oxide (AAO) membranes as wetting templates, nanotubes of the cylinder‐forming polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) copolymer were generated. The PS‐b‐PEO solution was introduced into the cylindrical nanopores of an AAO membrane by capillary force and polymeric nanotubes formed after solvent evaporation. Because of the water solubility of the cylindrical PEO microdomains and the orientation of the cylindrical PEO microdomains with respect to the nanotube walls, the nanotubes were permeable to aqueous media. PS‐b‐PEO nanotubes were also prepared on the interior walls of amorphous carbon nanotubes (a‐CNTs). Because of the unique water permeability of the PEO microdomains, an avenue for functionalizing the interior of the a‐CNTs is enabled. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2912–2917, 2007  相似文献   

14.
《Solid State Sciences》2012,14(8):1111-1116
Polymer electrolyte has been prepared via solution-casting technique. The polymer electrolytes are formed from polyethylene oxide (PEO) and lithium hexafluorate is used as the doping salt. The conductivity increases from 10−9 to 10−4 S cm−1 upon the addition of various concentrations of salt. The results reveal that the conductivity increases with increasing temperature when the salt concentration increases up to 20 wt% The conductivity for 20 wt% of salt remains similar to the conductivity for 15 wt% of salt at 318 K. Differential scanning calorimetry studies show that the melting transition temperature and crystallinity decreases upon the addition of various concentrations of salt. Thermogravimetric analysis (TGA) results indicate that a significant effect on the thermal stability of polyethylene–lithium salt composites. SEM images reveal that the morphology of polymer electrolyte's surface changes when various concentrations of salt are added into the polymer system.  相似文献   

15.
The tadpole‐shaped copolymers polystyrene (PS)‐b‐[cyclic poly(ethylene oxide) (PEO)] [PS‐b‐(c‐PEO)] contained linear tail chains of PS and cyclic head chains of PEO were synthesized by combination of Glaser coupling with living anionic polymerization (LAP) and ring‐opening polymerization (ROP). First, the functionalized polystyrene‐glycerol (PS‐Gly) with two active hydroxyl groups at ω end was synthesized by LAP of St and the subsequent capping with 1‐ethoxyethyl glycidyl ether and then deprotection of protected hydroxyl group in acid condition. Then, using PS‐Gly as macroinitiator, the ROP of EO was performed using diphenylmethylpotassium as cocatalyst for AB2 star‐shaped copolymers PS‐b‐(PEO‐OH)2, and the alkyne group was introduced onto PEO arm end for PS‐b‐(PEO‐Alkyne)2. Finally, the intramolecular cyclization was performed by Glaser coupling reaction in pyridine/Cu(I)Br/N,N,N′,N″,N″‐pentamethyldiethylenetriamine system under room temperature, and tadpole‐shaped PS‐b‐(c‐PEO) was formed. The target copolymers and their intermediates were well characterized by size‐exclusion chromatography, proton nuclear magnetic resonance spectroscopy, and fourier transform infrared spectroscopy in details. The thermal properties was also determined and compared to investigate the influence of architecture on properties. The results showed that tadpole‐shaped copolymers had lower Tm, Tc, and Xc than that of their precursors of AB2 star‐shaped copolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   

16.
A new, efficient method for synthesizing stable nanoparticles with poly(ethylene oxide) (PEO) functionalities on the core surface, in which the micellization and crosslinking reactions occur in one pot, has been developed. First, amphiphilic PEO‐b‐PS copolymers were synthesized by reversible addition fragmentation chain transfer (RAFT) radical polymerization of styrene using (PEO)‐based trithiocarbonate as a macro‐RAFT agent. The low molecular weight PEO‐b‐PS copolymer was dissolved in isopropyl alcohol where the block copolymer self‐assembled as core‐shell micelles, and then the core‐shell interface crosslink was performed using divinylbenzene as a crosslinking agent and 2,2′‐azobisisobutyronitrile as an initiator. The design of the amphiphilic RAFT agent is critical for the successful preparation of core‐shell interface crosslinked micellar nanoparticles, because of RAFT functional groups interconnect PEO and polystyrene blocks. The PEO functionality of the nanoparticles surface was confirmed by 1H NMR and FTIR. The size and morphology of the nanoparticles was confirmed by scanning electron microscopy, transmission electron microscopy, and dynamic laser light scattering analysis. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010  相似文献   

17.
Polymer electrolytes are of tremendous importance for applications in modern lithium‐ion (Li+‐ion) batteries due to their satisfactory ion conductivity, low toxicity, reduced flammability, as well as good mechanical and thermal stability. In this study, the Li+‐ion conductivity of well‐defined poly(ethylene oxide) (PEO) networks synthesized via copper(I)‐catalyzed azide–alkyne cycloaddition is investigated by electrochemical impedance spectroscopy after addition of different lithium salts. The ion conductivity of the network electrolytes increases with increasing molar mass of the PEO chains between the junction points which is completely opposite to the behavior of their respective uncrosslinked linear precursors. Obviously, this effect is directly related to the segmental mobility of the PEO chains. Furthermore, the ion conductivity of the network electrolytes under investigation increases also with increasing size of the anion of the added lithium salt due to a weaker anti‐plasticizing effect of the more bulky anions. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 21–28  相似文献   

18.
The 3‐miktoarm star‐shaped ABC copolymers of polystyrene–poly(ethylene oxide)–poly(ethoxyethyl glycidyl ether) (PS‐PEO‐PEEGE) and polystyrene–poly(ethylene oxide)–polyglycidol (PS‐PEO‐PG) with low polydispersity indices (PDI ≤ 1.12) and controlled molecular weight were synthesized by a combination of anionic polymerization with ring‐opening polymerization. The polystyryl lithium (PSLi+) was capped by EEGE firstly to form the functionalized polystyrene (PSA) with both an active ω‐hydroxyl group and an ω′‐ethoxyethyl‐protected hydroxyl group, and then the PS‐b‐PEO block copolymers, star(PS‐PEO‐PEEGE) and star(PS‐PEO‐PG) copolymers were obtained by the ring‐opening polymerization of EO and EEGE respectively via the variation of the functional end group, and then the hydrolysis of the ethoxyethyl group on the PEEGE arm. The obtained star copolymers and intermediates were characterized by 1H NMR spectroscopy and SEC.

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19.
We report the synthesis of a water‐soluble diblock copolymer composed of polysulfonic diphenyl aniline (PSDA) and poly(ethylene oxide) (PEO), which was prepared by reacting an amine‐terminated PSDA and tosylate PEO (PEO‐Tos). First, a HCl‐mediated polymerization of sulfonic diphenyl aniline monomer with the formation of HCl‐doped PSDA was carried out. After its neutralization and reduction, a secondary amine‐functionalized PSDA was obtained. Second, PEO‐Tos was synthesized via the tosylation of the monohydroxyl PEO methyl ether with tosylol chloride. Diblock copolymers with various PEO segment lengths (PSDA‐b‐PEO‐350 and PSDA‐b‐PEO‐2000) were obtained with PEO‐350 [number‐average molecular weight (Mn) = 350] and PEO‐2000 (Mn = 2000). The prepolymers and diblock copolymers were characterized by Fourier transform infrared spectroscopy, NMR, mass spectrometry, and ultraviolet–visible light. They had relatively low conductivities, ranging from 10?6 to 10?3 S/cm, because of the withdrawing effect of the sulfonic group as well as the steric effects of the bulky aromatic substitutuents at the N sites of the polyaniline backbone and of the PEO block. These polymers were self‐doped, and an intermolecular self‐doping was suggested. The external doping was, however, more effective. The self‐doping induced aggregation in water among the PSDA backbones, which was also stimulated by the presence of hydrophilic PEO blocks. Furthermore, the electrical conductivities of the diblock copolymers were strongly temperature‐dependent. PSDA‐b‐PEO‐2000 exhibited about one order of magnitude increase in conductivity upon heating from 32 to 57 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2179–2191, 2004  相似文献   

20.
The objective of this review is to organize literature data on the thermodynamic properties of salt‐containing polystyrene/poly(ethylene oxide) (PS/PEO) blends and polystyrene‐b‐poly(ethylene oxide) (SEO) diblock copolymers. These systems are of interest due to their potential to serve as electrolytes in all‐solid rechargeable lithium batteries. Mean‐field theories, developed for pure polymer blends and block copolymers, are used to describe phenomenon seen in salt‐containing systems. An effective Flory–Huggins interaction parameter, χeff , that increases linearly with salt concentration is used to describe the effect of salt addition for both blends and block copolymers. Segregation strength, χeffN , where N is the chain length of the homopolymers or block copolymers, is used to map phase behavior of salty systems as a function of composition. Domain spacing of salt‐containing block copolymers is normalized to account for the effect of copolymer composition using an expression obtained in the weak segregation limit. The phase behavior of salty blends, salty block copolymers, and domain spacings of the latter systems, are presented as a function of chain length, composition and salt concentration on universal plots. While the proposed framework has limitations, the universal plots should serve as a starting point for organizing data from other salt‐containing polymer mixtures. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1177–1187  相似文献   

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