Showing papers in "Polymer Bulletin in 1992"
TL;DR: In this paper, the authors synthesize polysquaraines and polycroconaines with a small band gap, down to 0.5 eV. The small gap arises from the regular alternation of strong donor and acceptor-like moieties in a conjugated backbone.
Abstract: Polysquaraines and polycroconaines have been synthesized. They form a new class of polymers with a small band gap, down to 0.5 eV. The small gap arises from the regular alternation of strong donor and acceptor-like moieties in a conjugated backbone.
365 citations
TL;DR: In this article, the synthesis and thermal degradability of poly (DL-lactide) were investigated and key factors affecting the polymer molecular weight were found to be monomer recrystallization, initiator concentration and the vacuum level during drying/sealing of the polymerization reaction ampoule.
Abstract: The synthesis and thermal degradability of poly (DL-lactide) were investigated. Key factors affecting the polymer molecular weight were found to be monomer recrystallization, initiator concentration and the vacuum level during drying/sealing of the polymerization reaction ampoule. It was found that poly (DL-lactide) is thermally unstable above its melting temperature. Monomer recrystallization, polymer precipitation and a low initiator content of the polymer significantly inhibited the rate and extent of thermal degradation.
109 citations
TL;DR: In this paper, the solid structure of a new group of transparent glass materials which consist of an organic polymer and a metal oxide, namely a combination of poly(vinylpyrrolidone) and dry silica gel, was analyzed by Atomic Force Microscopy (AFM), BET analysis method, and CP MAS13C-NMR.
Abstract: This paper is concerned with the solid structure of a new group of transparent glass materials which consist of an organic polymer and a metal oxide, namely a combination of poly(vinylpyrrolidone) and dry silica gel. The structure was analyzed by Atomic Force Microscopy (AFM), BET analysis method, and CP MAS13C-NMR. BET measurement showed that the hybrid material had a quite dense structure which was much less porous than the reference dry silica gel prepared by the conventional sol-gel process. AFM analysis gave the same conclusion, i.e., it showed a granular structure of silica of about 1 nm size. Silica and PVP domains did not show any considerable aggregation. The transparent, homogeneous, and dense structure was attributed to the hydrogen-bond formation between PVP(carbonyl group) and silanol, as demonstrated by CP MAS13C-NMR spectroscopy.
81 citations
TL;DR: In this article, the impact strength of as-polymerized poly(L-lactide), (PLLA), has been investigated and copolymerization with trimethylene carbonate and e-caprolactone, block copolymization with rubbers and the plasticization with ethyl acetate have been explored.
Abstract: As-polymerized poly(L-lactide), (PLLA), has a much higher impact strength than after compression moulding. Several routes have been explored to further increase the impact strength of nascent PLLA. First results on the preparation of composites with carbon fibres, the copolymerization with trimethylene carbonate and e-caprolactone, the block copolymerization with rubbers and the plasticization with ethyl acetate indicate possibilities to prepare much more impact resistant as-polymerized PLLA materials.
78 citations
TL;DR: In this article, a fluorescence method is described for the measurement of the rate of exchange of chains between micelles formed by diblock copolymers in aqueous solution.
Abstract: A fluorescence method is described for the measurement of the rate of exchange of chains between micelles formed by diblock copolymers in aqueous solution. The method requires two samples of the diblock copolymer. One sample is labelled with a Forster donor, the other sample is labelled with a Forster acceptor. Successful application of the method is demonstrated with diblock copolymers composed of polystyrene and poly(ethylene oxide). The donor and acceptor are naphthalene and pyrene, respectively. The label is covalently attached to the copolymers at the junction points between the two blocks. Solutions with micelles are formed independently by the two labelled samples. At the time of mixing of the two solutions, no micelle contains both a donor and an acceptor. Micelles containing both types of labels may be formed at later times as a consequence of the exchange of labelled chains. The efficiency of nonradiative singlet energy transfer from naphthalene to pyrene is measured as a function of time after mixing of the two solutions. At 60° C the rate constant deduced from the time dependence of the fluorescence is on the order 10-5 s-1. At ambient temperature, however, no exchange can be detected, presumably because of the difficulty in extraction of a polystyrene block from the glassy core.
56 citations
TL;DR: In this paper, a method for determining the absolute rate constants for the first few propagation steps in radical polymerization is described, which involves a product analysis of the oligomeric alkoxyamines formed when an initiator is decomposed in monomer containing a very low concentration of a nitroxide radical scavenger.
Abstract: A method is described for determining the absolute rate constants for the first few propagation steps in radical polymerization. The procedure involves a product analysis of the oligomeric alkoxyamines formed when an initiator is decomposed in monomer containing a very low concentration of a nitroxide radical scavenger. The method is illustrated with analysis of data for methyl acrylate. The rate constants for the first two propagation steps for polymerization of this monomer,k
p(1) andk
p(2), are at least an order of magnitude greater thank
p(average). Values of the absolute rate constants for reactions of phenyl and primary alkyl radicals with methyl acrylate are also estimated.
54 citations
TL;DR: In this paper, the polymerization of styrene in the presence of mercapto-amine or carboxylic acid derivatives could successfully introduce amino and carboxyl group on the poly(styrene)/SiO2 composite.
Abstract: Radical polymerizations of vinyl monomers using a initiator of 2,2′-azobis(2-amidinopropane) dihydrochloride on monodispersed silica colloid led to formation of spherical polymer/SiO2 composites, retained particle size. Addition of hydroxypropyl cellulose to the reaction system resulted in yielding excellent dispersible composites into ethanol by short period ultrasonic irradiation. The polymerization of styrene in the presence of mercapto-amine or carboxylic acid derivatives could successfully introduce amino or carboxyl group on the Poly(styrene)/SiO2 composite.
52 citations
TL;DR: In this article, the substitution patterns of methyl cellulose as well as of a thexyldimethylsilyl cellulose after permethylation were determined by hydrolysis and separation of the resulting partially methylated glucoses without further derivatization by h.p.l.
Abstract: The substitution patterns of methyl cellulose as well as of a thexyldimethylsilyl cellulose after permethylation were determined by hydrolysis and separation of the resulting partially methylated glucoses without further derivatization by h.p.l.c.. On an amine-modified silica column the solutes get separated into glucose, 2,3,6-tri-O-methyl glucose and the groups of mono-O-methyl-and di-O-methyl glucoses. A chromatographic run on a reversed-phase column enables the identification of the single mono-O-methyl- and di-O-methyl glucoses. In this way, a determination of both the average degree of substitution and the substitution pattern of cellulose derivatives is possible. Comparison of the results with those obtained by standard methylation analysis including g.l.c.-m.s. proves the correctnes of the method employed.
52 citations
TL;DR: The balance of polar/nonpolar forces on the interfaces of various amphiphilic networks comprising hydroxyethyl methacrylate or N,N-dimethylacrylamide hydrophilic chains linked by polyisobutylene hydrophobic chains in contact with water have been studied by dynamic contact angle measurements as mentioned in this paper.
Abstract: The surface energetics, specifically the balance of polar/nonpolar forces on the interfaces of various amphiphilic networks comprising hydroxyethyl methacrylate or N,N-dimethylacrylamide hydrophilic chains linked by polyisobutylene hydrophobic chains (for brevity H and A networks) in contact with water have been studied by dynamic contact angle measurements. Both networks show large contact-angle hysteresis due to surface heterogenity and surface rearrangements. The balance of the polar/nonpolar forces of the dry networks is much below unity
51 citations
TL;DR: In this paper, a blend membrane consisting of polyvinyl alcohol (PVA) and chitosan was prepared from solvent casting technique for effective separation of ethanol-water mixture by pervaporation.
Abstract: Blend membrane consisting of poly(vinyl alcohol)(PVA) and chitosan was prepared from solvent casting technique for effective separation of ethanol-water mixture by pervaporation. Selectivity toward water and the flux through the blend membrane, crosslinked with glutaraldehyde at the concention of 4×10-6 mol/g, were∼450 and 0.47 kg/m2.hr, respectively.
48 citations
TL;DR: In this article, the authors investigated the kinetics of the reaction between a styrene-maleic anhydride copolymer and amines in tetrahydrofuran solution between 0°C and 40°C.
Abstract: The kinetics of the reaction between a styrene-maleic anhydride copolymer (SMA) and amines was investigated in tetrahydrofuran solution between 0°C and 40°C. This reaction converts the maleic anhydride (MA) into the corresponding amide-acid, while the consecutive reaction of the generated acid with amine forming a diamide or transformation of the acid-amide into the imide was not observed. The amine reactivity follows the order: 1-octylamine> >1-methyl hexylamine> >1,1-dimethyl propylamine or dibutylamine, demonstrating that the amine reactivity depends, to a large extent, upon its steric hindrance. This reaction is reversible as shown by IR at high temperatures, but the reverse reaction was undetectable between 0 and 40°C. The overall reaction involves spontaneous and autocatalytic reactions, and the overall reaction rate can be written as:-d[MA]/dt=k0[MA][-NH2]+k1[MA][-NH0]2. In the case of 1-octylamine below 0.02 M, the spontaneous reaction dominates (i.e, k0> >k1[-NH2]).
TL;DR: In the presence of proton trap 2,6-di-tert-butylpyridine (DTBP) in concentrations comparable to that of protic impurities, living polymerization of isobutylene (IB) has been achieved with 2,4,4-trimethylpentyl chloride (TMPCl) or cumyl chloride(CumCl)/BCl3/(IB)/methyl chloride/-40°C system.
Abstract: The living polymerization of isobutylene (IB) has been achieved with the 2,4,4-trimethylpentyl chloride (TMPCl) or cumyl chloride (CumCl)/BCl3/(IB)/methyl chloride/-40°C system in the presence of proton trap 2,6-di-tert-butylpyridine (DTBP) in concentrations comparable to that of protic impurities. According to kinetic studies the polymerization is first order both in respect to monomer and BCl3. The polymerization rate is not effected by the excess DTBP which suggests that the livingness is not due to carbocation stabilization. Comparison of the results in the presence of DTBP and/or dimethyl sulfoxide (DMSO) demonstrated that the main function of the electron donor (ED) DMSO is to trap protic impurities. The assumption of carbocation stabilization is unnecessary, and reversible termination and the absence of chain transfer is sufficient to explain livingness. In the absence of proton trap or ED however, fast polymerization by the protic impurities occurs masking the much slower living polymerization and the monomer is consumed mainly by this process unless the protic impurities are scavenged.
TL;DR: Group-transfer polymerization of benzyl methacrylate has been shown to proceed smoothly to give polymers of low polydispersity, with good control of molecular weight as mentioned in this paper.
Abstract: Group-transfer polymerization of benzyl methacrylate has been shown to proceed smoothly to give polymers of low (Mw/Mn < 1.1) polydispersity, with good control of molecular weight. Removal of the benzyl groups can be achieved easily via catalytic hydrogenation at room temperature and takes place without main chain scission. This is thus a very effective route for the synthesis of monodisperse poly(methacrylic acid)s.
TL;DR: The Mark Houwink exponent relating intrinsic viscosity and the molecular weight are usually much larger for polysaccharides than for synthetic polymers in a moderate range of molecular weights as discussed by the authors.
Abstract: The Mark Houwink exponent relating intrinsic viscosity and the molecular weight are usually much larger for polysaccharides than for synthetic polymers. In a moderate range of molecular weights, it depends directly on the stiffness of the molecules considered as worm like chains. This paper demonstrates that these exponents are predictible from the model of Yamakawa-Fujii.
TL;DR: In this paper, the catalytic activity of the system Nd(carboxylate)/t-butyl chloride/Al(i-Bu) 2 H (Carboxylates = naphtenate, versatate) for the preparation of polybutadiene with high cis content was studied.
Abstract: The catalytic activity of the systems Nd(carboxylate)/t-butyl chloride/Al(i-Bu) 2 H (carboxylate = naphtenate, versatate) for the preparation of polybutadiene with high cis content was studied. Stable catalyst which give relatively monodisperse polymers are given by componetnt addition order Nd(carboxylate) 3 +Al(i-Bu) 2 H + t-BuCl.
TL;DR: In this paper, a three-component polymerized (oil in water) microemulsions, stabilized by cationic surfactants, were made by Murtagh, Ferrick, and Thomas [ACS Polymer Preprints 16] and more recently by Perez-Luna, Puig, Castano, Rodriguez, Murthy, and Kaler [Langmuir1990, 6, 1040].
Abstract: Part of the phase diagram at low (<10%) oil content and 25°C has been mapped in the water, Aerosol-OT (AOT), tetrahydrofurfuryl methacrylate (THFM) ternary system. Sodium persulfate/sodium metabisulfite was used as a redox initiator to induce polymerization in this microemulsion system at 7.8% (w/w) THFM and 4.4% AOT. Conversions in excess of 90% were obtained. The parent microemulsion droplets have diameters on the order of 5 nm. The resulting latexes have average particle diameters of 37–39 nm. The latex particles are cross-linked as a result of radical induced opening of the tetrahydrofurfuryl ring, and exhibit nearly the same density (1.216 g/cm3) and glass transition temperature (67°C) as material (1.222 g/cm3; 62°C) produced by solution polymerization. This three-component microemulsion, and the corresponding latexes, have been imaged directly by cryo-electron microscopy. The first reports of three-component polymerized (oil in water) microemulsions, stabilized by cationic surfactants, were made by Murtagh, Ferrick, and Thomas [ACS Polymer Preprints
1987, 28, 441] and more recently by Perez-Luna, Puig, Castano, Rodriguez, Murthy, and Kaler [Langmuir
1990, 6, 1040]. this report appears to be the first such polymerization in a three-component system stabilized with an anionic surfactant. These latexes are cross-linked beads, and are the first such examples to be prepared by microemulsion polymerization.
TL;DR: In this article, the mixture of bacterial poly(3-hydroxybutyrate-co-3hydroxyvalerate) with cellulose acetate butyrate (CAB) and cellulose acyclic propionate (CAP) was prepared by melt blending, and when CAB or CAP content in the blends is ≥ 50%, the blends are stable, homogeneous mixed glasses, characterized by a glass transition that follows the Fox equation.
Abstract: Blends of bacterial Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with cellulose acetate butyrate (CAB) and cellulose acetate propionate (CAP) were prepared by melt blending. When CAB or CAP content in the blends is ≥ 50%, the blends are stable, homogeneous mixed glasses, characterized by a glass transition that follows the Fox equation. When the cellulose ester content is lower than 50%, PHBV crystallizes upon room storage and the blends are partially crystalline. Besides the strongly composition dependent glass transition, another slightly composition dependent relaxation is observed by both DMTA and DSC measurements in the vicinity of the glass transition of PHBV. It is suggested that both blend components partake in both mobilization processes.
TL;DR: Two separation techniques have been investigated, namely Aqueous Size Exclusion Chromatography using a Bio-Gel P2 gel column and High Performance Capillary Electrophoresis, used to control the efficiency of oligomer fractionation by the dissolution/precipitation method.
Abstract: Poly (β-malic acid) is a functional aliphatic polyester which can serve as parent compound to make systems aimed at temporary therapeutic applications. Degradation of the polyester backbone of poly(β-malic acid) leads to the formation of oligomers which can be hardly separated by conventional Size Exclusion Chromatography. In order to monitor the formation of oligomeric degradation by-products and to quantify their relative amount, the potential of two separation techniques has been investigated, namely Aqueous Size Exclusion Chromatography using a Bio-Gel P2 gel column and High Performance Capillary Electrophoresis. Aqueous SEC allowed separation of oligomers smaller than hexamer whereas HPCE successfully separated oligomers smaller than pentadecamers. These techniques were used to control the efficiency of oligomer fractionation by the dissolution/precipitation method.applied to the sodium salt of poly(β-malic acid).
TL;DR: Isotactic (it-) and syndiotactic (st-) MMA oligomers from 19-mer to 29-mer could be isolated efficiently from it-PMMA (DP=28.6) and st-MMA (DP =26.8) by the SFC using a 10 mm i.d. x 250 mm column packed with silica gel.
Abstract: Isotactic (it-) and syndiotactic (st-) MMA oligomers from 19-mer to 29-mer could be isolated efficiently from it-PMMA (DP=28.6) and st-PMMA (DP=26.8) (sample load: 50 mg) by the SFC using a 10 mm i.d. x 250 mm column packed with silica gel. T g of the it-28-mer measured by DSC was 34.5°C, which was higher than that of the it-PMMA by 6.5°C. T g of both the it- and st-oligomers increased linearly with DP in the range of DP of 20-29. A 1:1 mixture of the it- and st-27-mers annealed at 140°C showed an exsothermic transition at 102.3 °C which was attributable to melting of stereocomplex
TL;DR: A series of three aromatic polyamide dendrimers prepared via a convergent growth approach and are monodisperse by GPC are reported and some conformational effects that can be observed in their1H NMR spectra are reported.
Abstract: A series of three aromatic polyamide dendrimers are reported. The materials were prepared via a convergent growth approach and are monodisperse by GPC. We have analysed the dendrimers by a variety of standard techniques and report some conformational effects that can be observed in their1H NMR spectra.
TL;DR: In this paper, anionic ring opening polymerization of 1-methyl-1-silacyclobutane, 1-phenyl- 1-silaclobutanes and 1-silia-clobutsane co-catalyzed by n-butyllithium and hexamethylphosphoramide (HMPA) in THF at-78°C yields poly(1-methyl, 1 -silabutane), poly(phenyl, 1 −silacclobuttane) and poly( 1 −sia-cl
Abstract: Anionic ring opening polymerization of 1-methyl-1-silacyclobutane, 1-phenyl-1-silacyclobutane and 1-silacyclobutane co-catalyzed by n-butyllithium and hexamethylphosphoramide (HMPA) in THF at-78°C yields poly(1-methyl-1-silabutane), poly(1-phenyl-1-silabutane) and poly(1-silabutane) respectively. These saturated carbosilane polymers possess reactive Si-H bonds. They have been characterized by 1H, 13C and 29Si NMR as well as FT-IR and UV spectroscopy. Their molecular weight distributions have been determined by gel permeation chromatography (GPC), thermal stabilities by thermogravimetric analysis (TGA) and glass transition temperatures (Tg) by differential scanning calorimetry (DSC).
TL;DR: In this paper, the results of atomic force microscopy (AFM) on carbon fibers from polyacrylonitrile and pitch are presented in comparison with Scanning Electron Microscopy (SEM) and Scanning Tunneling MicroScopy (STM) images.
Abstract: Results of Atomic Force Microscopy (AFM) on carbon fibers from polyacrylonitrile and pitch are presented in comparison with Scanning Electron Microscopy (SEM) and Scanning Tunneling Microscopy (STM) images Single fiber surfaces and their crosssections have been imaged on scales from microns to nanometers Morphological details beyond the resolution of SEM were revealed by AFM and STM Grain-type structure was verified on surface of numerous nanofibrils orlented along the main fiber direction Grains are bigger on pitch-based fibers generally, and on fibers of both types after treatment at higher temperatures In the atomic scale AFM images traces of graphitic structure were recorded AFM artefacts on rough surfaces are demonstrated ac19920414
TL;DR: In this article, the mesophase formation of a ternary system consisting of a solvent, a rigid rod solute (imogolite), and a randomly coiled polymer chain (poly(vinyl alcohol); PVA) was observed.
Abstract: The mesophase formation was observed in the ternary system consisting of a solvent, a rigid rod solute (imogolite), and a randomly coiled polymer chain (poly(vinyl alcohol); PVA). Although the mesophase formation in this system seems to follow qualitatively the scheme presented by Flory, no marked segregation of the two solute component was confirmed. The physical properties of the composite film prepared from this ternary system were also examined.
TL;DR: In this article, the 300 and 600 MHz 1H-NMR spectra of poly(3-vinyl thiophene) synthesized via free radical initiated polymerization are presented and analyzed.
Abstract: The 300 and 600 MHz1H-NMR spectra of poly-(3-vinyl thiophene) synthesized via free radical initiated polymerization are presented and analyzed. The spectra are similar to those of poly-(2-vinyl thiophene) and were interpreted in a like manner. The polymer was found to be atactic with a Pm value of 0.48±.05.
TL;DR: In this article, a multiblock-(A-B)n-copolymers containing polyester segments together with perfluoropolyether (PFPE) segments have been prepared by polymerizing dimethyl terephthalate (DMT), or an equimolar mixture of DMT and dimethyl isophthalate, with ethylene glycol (EG) in the presence of different telechelic perfluorsopolyethers in various amounts (5 − 30 wt), using Tl(OBu)4 as the catalyst.
Abstract: Multiblock-(A-B)n-copolymers containing polyester segments together with perfluoropolyether (PFPE) segments have been prepared by polymerizing dimethyl terephthalate (DMT), or an equimolar mixture of DMT and dimethyl isophthalate (DMI), with ethylene glycol (EG) in the presence of different telechelic perfluoropolyethers in various amounts (5–30 wt%), using Tl(OBu)4 as the catalyst. Fomblin ZDEAL (a-COOCH3 terminated PFPE), Fomblin ZDOL (a PFPE having-CH2OH terminal groups), and Fomblin ZDOLTX (a PFPE having-CH2O(CH2CH2O)yH terminal groups) were used as telechelic PFPEs. Fomblin ZDOLTX gave the best results: the highest yield in block copolymer (less sensitive to hydrolysis with respect to block copolymers prepared from the other PFPEs), a longer average length of polyester segments, and a relatively low fraction of PFPE lost by distillation during polymerization.
TL;DR: In this article, an electroactive polymer blend comprising polyaniline (PANI) as conductive component and poly(methyl methacrylate) (PMMA), polystyrene (PS) and methyl methacricrylate-butadiene-styrene copolymer as a thermoplastic constituent (TC) were prepared by using various techniques: in situ by oxidative polymerization of aniline in aqueous dispersions of the TC; by, coagulating of latex of TC in the acidic dispersions wherein PANI has been preliminary obtained
Abstract: Electroactive polymer blends comprising polyaniline (PANI) as conductive constituent and poly(methyl methacrylate) (PMMA), polystyrene (PS) and methyl methacrylate-butadiene-styrene (MBS) copolymer as a thermoplastic constituent (TC) were prepared by using various techniques:in situ by oxidative polymerization of aniline in aqueous dispersions of the TC; by, coagulating of latex of TC in the acidic dispersions wherein PANI has been preliminary obtained; and by dry blending. It was shown that highest conductivity values revealedin situ prepared PANI/PMMA blends, where the intermolecular interactions between the constituents were suggested to be stronger than in the other systems studied.
TL;DR: The pyridinium salt of partially chloromethylated poly(methylphenysilylene) (Q-PMPSi) in aqueous solution is capable of initiating the polymerization of hydrophilic vinyl monomers, e.g. acrylic and methacrylic acid, acrylamide, 2-hydroxyethyl methacrylate and 1-vinyl-2-pyrrolidone.
Abstract: Radicals formed during photoscission of the pyridinium salt of partially chloromethylated poly(methylphenysilylene) (Q-PMPSi) in aqueous solution are capable of initiating the polymerization of hydrophilic vinyl monomers, e.g. acrylic and methacrylic acid, acrylamide, 2-hydroxyethyl methacrylate and 1-vinyl-2-pyrrolidone.
TL;DR: In this paper, a novel approach to monodispersed porous polymer beads allowing accurate control over a broad range of pore size distribution has been developed, which involves the use of template particles which are used as polymeric porogens in the suspension polymerization of monomers such as styrene and divinylbenzene.
Abstract: A novel approach to monodispersed porous polymer beads allowing accurate control over a broad range of pore size distribution has been developed. It involves the use of monodispersed template particles which are used as polymeric porogens in the suspension polymerization of monomers such as styrene and divinylbenzene. The size uniformity of the template particles is retained by the final porous beads. The porous properties of the final beads are determined in large part by the characteristics of the porogenic mixture such as its composition, the molecular weight of the polymeric porogen, as well as the relative amount of monomers, polymeric and low molecular weight porogens used.
TL;DR: In this paper, LiCF3SO3 and a polymer obtained by polymerization of triethylene glycol dimethacrylate (TRGDMA) and its copolymerization with acrylonitrile (AN) at molar ratios of 0.67, 2.0 and 4.
Abstract: Complexes of LiCF3SO3 and a polymer obtained by polymerization of triethylene glycol dimethacrylate (TRGDMA) and its copolymerization with acrylonitrile (AN) at molar ratios of 0.67, 2.0 and 4.0, both in the presence of poly(ethylene glycol) dimethylether as a plasticizer, provides a.c.conductivities in the range between 10-5 and 10-4 S/cm at ambient temperature. An increase of conductivities has been found at growing ratios of [AN]:[TRGDMA] from 0 to 2.0 and molar ratios of ethylene oxide (EO) units: LiCF3SO3 ranging from 12 to about 26. The conductivity is nearly independent on the content of AN at [EO]:[Li+]=52.
TL;DR: In this article, a polyglutamates bearing azobenzene derivatives covalently bound to the main chain via spacers and equipped with alkyl tails of different length have been synthesized.
Abstract: Polyglutamates bearing azobenzene derivatives covalently bound to the main chain via spacers and equipped with alkyl tails of different length have been synthesized. In the polymers the chromophore can be isomerized to high extent by irradiation with UV-light. The polymers can be spread on a LANGMUIR trough. The spreading behaviour is different for irradiated and non irradiated samples, indicating a different arrangement depending on the content of cis-isomer. The films are less stable for longer spacers and smaller tails, caused by the better interaction of the azobenzene groups due to the greater mobility and minor hindrance.