Chemically modified nylons as supports for enzyme immobilization

An isocyanide derivative of nylon, polyisonitrile-nylon (1,2), was used as a starting material whereby, through a series of modification reactions, different chemically reactive functional groups could be introduced on the polyamide backbone. The chemistry employed allowed for considerable flexibility in the choice of procedures for covalent fixation of proteins, all starting from the same chemically reactive parent polymer, polyisonitrile-nylon. Thus, polyisonitrilenylon could be used directly for the immobilization of enzymes via fourcomponent condensation reactions. The isocyanide functional groups of the parent polymer could be transformed, by treatment with bromine, into the strongly electrophilic dibromoisocyanide (—N=CBr^b2) groups. The selectivity of the —N=CBr^b2 group toward the various functional groups present in proteins could be regulated by appropriate control of the pH of the coupling reaction. Dibromoisocyanide-nylon was also further modified into other types of chemically reactive nylon derivatives.     

Additive‐dependent iptycene incorporation in polyanilines: Insights into the pentiptycene clipping effect and the polymerization mechanism

Despite the long history of polyaniline chemistry, backbone‐substituted polyanilines are limited. Here, we report the synthesis of pentiptycene‐incorporated polyanilines through acidic aniline oxidative polymerization with three pentiptycene derivatives, TA, DA, and TP, as nucleate additives. The reactivity of TA > DA ? TP, as evidenced by structural and property analysis of the corresponding polyaniline products, demonstrates a radical coupling mechanism and the formation of Dewar π‐complex intermediates for the chain propagation. In addition, the iptycene substituent effect on enhancing the electrochemical stability and charge storage capability of polyaniline are discussed with a clip model, namely, the threading of neighboring polyaniline chains through the U‐ and V‐shaped cavities of pentiptycene restricts lateral motions of the polymer chains and promotes interchain conductivity. Density function theory (DFT) calculations suggest a larger clipping effect for the U versus V cavities. Both the conclusion of a terminal planar p‐phenylenediamine (ppda) group being the key component of an effective nucleate and the concept of interchain clipping for enhanced electrochemical performance should facilitate the design and synthesis of novel polyanilines for electronic applications.     

Post-synthetic ‘Click’ Synthesis of RAFT Polymers with Pendant Self-immolative Triazoles

Self-immolative linkers offer efficient mechanisms for deprotecting ‘caged’ functional groups in response to specific stimuli. Herein we describe a convenient ‘click’ chemistry method for introducing pendant self-immolative linkers to a polymer backbone through post-polymerization modification. The introduced triazole rings serve both to anchor the stimuli-cleavable trigger groups to the polymer backbone, while also forming a functional part of the self-immolation cascade. We investigate the polymerization kinetics, post-synthetic modification, and self-immolation mechanism of a model polymer system, and discuss avenues for future studies on poly-pendant self-immolative triazoles as a modular, stimuli-responsive macromolecule platform.     

Substitution and condensation reactions with poly(anilineboronic acid): reactivity and characterization of thin films

Poly(anilineboronic acid) thin films are treated under various conditions to achieve substitution or condensation reactions involving the boronic acid moiety. These reactions are studied with polarization modulated infrared reflection absorption spectroscopy, cyclic voltammetry, and UV-vis spectroscopy. The results suggest the single-step formation of substituted polyanilines, such as poly(hydroxyaniline), halogenated polyanilines, and mercury chloride-substituted polyaniline. A condensation reaction of poly(anilineboronic acid) with cis-diol compounds in aqueous solution, as well as with phenylenebisboronic acid and salycilamide in THF, indicates the formation of boronic esters. The latter reactions appear to be a good entry point for the formation of complex or supramolecular polymer structures.     

Organic polymer leds with mobile and immobile ions

The syntheses of partially conjugated alkoxy substituted Poly(p-phenylenevinylene) (PPV) materials with tertiary amines and cationic species covalently bound to the polymer backbone are described. The amine/cationic species are introduced via a polymer analogous reaction of a functional alcohol and the chloro-precursor polymer. Single layer, polymer light emitting diodes (PolyLEDs), prepared with the modified polymer materials show a strong ‘burn-in’ effect, leading to very high electroluminescence (EL) quantum efficiencies especially with higher workfunction cathodes.     

Thiophene-based polyphosphazenes with tunable optoelectronic properties

The polyphosphazene backbone provides a versatile platform to explore numerous synthesis and structure–property relationships for many technological applications. In this study, a new class of polyphosphazene semiconducting materials was synthesized via macromolecular substitution, which integrates a  PN backbone with thiophene-based side groups. The synthesized thiophene-based polymers were subjected to chemical oxidation (oxidative coupling) to optimize their optoelectronic properties through side-chain chemistry. Both the spectroscopic and electronic analyses revealed that optical and electronic properties, as well as glass transition temperatures could be modulated by chemical oxidation of the polymers. The suitability of the polymers as potential semiconductors was further evaluated using their steady-state fluorescence quenching behavior in the presence of four different dopants (PC70BM, PC60BM, F4TCNQ, and TCNQ). It was found that the addition of dopant as a quencher to the polymer solutions does not form a complex in the ground state, and its excited state shows an efficient decrease in fluorescence intensity without altering the shape and peak position of the fluorescence band. The overall results demonstrate that the utilization of chemical oxidation via side-chain chemistry of polyphosphazenes offers an adaptable toolbox that can be used to make new and potentially useful polymeric semiconductors for applications in organic electronics.     

Synthesis and reactions of N-heterocyclic carbene boranes

Boranes are widely used Lewis acids and N-heterocyclic carbenes (NHCs) are popular Lewis bases, so it is remarkable how little was known about their derived complexes until recently. NHC-boranes are typically readily accessible and many are so stable that they can be treated like organic compounds rather than complexes. They do not exhibit "borane chemistry", but instead are proving to have a rich chemistry of their own as reactants, as reagents, as initiators, and as catalysts. They have significant potential for use in organic synthesis and in polymer chemistry. They can be used to easily make unusual complexes with a broad spectrum of functional groups not usually seen in organoboron chemistry. Many of their reactions occur through new classes of reactive intermediates including borenium cations, boryl radicals, and even boryl anions. This Review provides comprehensive coverage of the synthesis, characterization, and reactions of NHC-boranes.     

Highly conductive and thermally stable self-doping propylthiosulfonated polyanilines

A new type of highly conductive self-doping polyaniline, MPS-Pan, containing a sulfonic acid moiety covalently bonded to the polymer backbone through an electron-donating propylthio linkage has been successfully prepared via a novel concurrent reduction and substitution route. At a similar self-doping level, the resultant MPS-Pans displayed much higher conductivity than the corresponding sulfonated-polyaniline (S-Pan). Furthermore, for fully doped samples, contrary to the trend of decreasing conductivity with the sulfonation degree in S-Pan, the conductivity of MPS-Pan was found to increase with its substitution degree. These results agreed with the expectation that electron-deficient charge carriers (e.g. semiquinone radical cations) on acid-doped polyaniline chains will be better stabilized by the electron-donating alkylthio-substituent. Surprisingly, TG and XPS studies showed that MPS-Pan was thermally much more stable than S-Pan, with S-Pan started to lose its sulfonic acid dopant at 185 ℃, while MPS-Pan remained intact up to ca. 260 ℃.     

The synthesis and properties of a series of novel side-chain liquid crystal polymers based on the Baylis-Hillman reaction

A new methodology is described, based on the Baylis-Hillman reaction, by which thermally stable side-chain liquid crystal (SCLC) polymers can be prepared incorporating a variety of functional groups along the polymer backbone. This methodology also allows a polar group, especially hydroxyl, to be inserted adjacent to the point of attachment of the spacer group to the polymer backbone. The spatial arrangement of the hydroxyl and functional groups is not only conducive to the formation of liquid crystalline phases but may also influence the tacticity of the polymer backbone.     

聚苯胺类/n-Si(111)单晶硅复合电极:制备与光电性质

在过氧化月桂酰作用下,于n-Si(111)型单晶硅表面上分别嫁接苯胺及烷基取代苯胺,进而实现晶体硅表面上聚苯胺和烷基取代聚苯胺的原位聚合,制备得到了系列聚苯胺(或烷基取代聚苯胺)/n-Si(111)单晶硅复合电极。此外,对上述合成电极表面苯胺链进行磺化,得到系列磺酸基化的单晶硅复合电极。电化学研究结果显示,聚苯胺直接嫁接于晶体硅表面所得到的复合电极光电转化效率最高,苯胺聚合链通过碳碳双键桥连于单晶硅表面所得到复合电极的光电转化效率高于通过碳碳单键桥连得到的复合电极,但其光电转化效率低于苯胺聚合链直接桥连于晶体硅表面而得到的复合电极。另外发现,苯环磺酸基化有利于提高复合电极的光电转化效率。     

SYNTHESIS AND CHARACTERIZATION OF POLYMERS BEARINGAZOBENZENE AND CARBAZOLE GROUPS VIA POST-AZO-COUPLING REACTION

A series of polymers bearing azobenzene and carbazole groups for photorefractive purpose were prepared viapost-azo-coupling reaction.The successful reaction was identified by spectroscopic analysis and gel permeationchromatography.This approach is more facile compared with the direct polymerization of corresponding functionalmonomer.The polymers prepared have weight average molecular weight of higher than 1.5×10~4 and are easily soluble incommon organic solvents like chloroform and tetrahydrofuran,polymer films with high optical quality could be easilyfabricated through solution casting.Glass transition temperature (T_(?)) of the polymers ranges from 60℃to 182℃,dependingon the alkylene spacer length between the functional side group and the polymer backbone,and the polymers are relativelystable under 300℃.     

Polysiloxane‐Backbone Block Copolymers in a One‐Pot Synthesis: A Silicone Platform for Facile Functionalization

Block copolymers consisting exclusively of a silicon–oxygen backbone are synthesized by sequential anionic ring‐opening polymerization of different cyclic siloxane monomers. After formation of a poly(dimethylsiloxane) (PDMS) block by butyllithium‐initiated polymerization of D3, a functional second block is generated by subsequent addition of tetramethyl tetravinyl cyclotetrasiloxane (D4^V), resulting in diblock copolymers comprised a simple PDMS block and a functional poly(methylvinylsiloxane) (PMVS) block. Polymers of varying block length ratios were obtained and characterized. The vinyl groups of the second block can be easily modified with a variety of side chains using hydrosilylation chemistry to attach compounds with Si—H bond. Conversion of the hydrosilylation used for polymer modification was investigated.     

Transparent Films from CO2‐Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing

Transparent films were prepared by cross‐linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO₂, propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron‐acceptor and electron‐donor groups enables particularly facile UV‐ or redox‐initiated free‐radical curing. The resulting materials are transparent and highly interesting for coating applications.     

聚苯胺类/n-Si(111)单晶硅复合电极:制备与光电性质

在过氧化月桂酰作用下,于n-Si(111)型单晶硅表面上分别嫁接苯胺及烷基取代苯胺,进而实现晶体硅表面上聚苯胺和烷基取代聚苯胺的原位聚合,制备得到了系列聚苯胺(或烷基取代聚苯胺)/n-Si(111)单晶硅复合电极。此外,对上述合成电极表面苯胺链进行磺化,得到系列磺酸基化的单晶硅复合电极。电化学研究结果显示,聚苯胺直接嫁接于晶体硅表面所得到的复合电极光电转化效率最高,苯胺聚合链通过碳碳双键桥连于单晶硅表面所得到复合电极的光电转化效率高于通过碳碳单键桥连得到的复合电极,但其光电转化效率低于苯胺聚合链直接桥连于晶体硅表面而得到的复合电极。另外发现,苯环磺酸基化有利于提高复合电极的光电转化效率。     

聚硅烷的电化学合成

聚硅烷是一类链骨架中仅含硅原子的高聚物,主链的上的非定域σ键电子赋予了聚硅烷独特的光电性质,也是制备陶瓷材料的先驱体。电化学法是最近兴起且具发展前景的一种合成聚硅烷的方法,它是通过电解池中阴极还原氯硅烷来制取高聚物,反应条件温和,且能大大拓宽聚硅烷的功能化。本文就聚硅烷的电化学合成的实施方法;影响因素包括电解槽类型、电...     

聚苯胺-木质素磺酸复合物的合成及其染料吸附性能——介绍一个综合性研究型实验

以苯胺为单体,木质素磺酸为分散剂,采用化学氧化聚合法合成成本低廉、吸附性能优异的聚苯胺-木质素磺酸(PAL)复合物。要求学生掌握复合物的合成操作步骤、复合物的表征及其染料吸附性能测试的方法。通过对比实验结果,为研究型实验教学提供思路。该实验利于加深学生对高分子学科知识的理解与运用,培养他们的综合实验能力。     

Synthesis and characterization of poly[N-((10-phenothiazinyl)-6-hexanoyl)ethylenimine] and N,N-diethyl-6-(10-phenothiazinyl)-hexanamide

A new oxazoline monomer was made containing a chloroalkyl substituent which can be transformed to other functional groups by nucleophilic substitution. Oxazoline monomer containing the N-phenothiazinyl substituent was made by reacting lithiated phenothiazine with the chloroalkyl substituted oxazoline and subsequently polymerized. N,N-diethyl-6-chlorohexanamide was synthesized and N,N-diethyl-6-(10-phenothiazinyl)-hexanamide, a model compound for the phenothiazine polymer, was made by reacting lithiated phenothiazine with this chloroamide. TCNQ did not complex with the polymer. The iodine and perchlorate complexes of the phenothiazine polymer had conductivities of 4.4 × 10 ^?8 and 6.9 × 10^?6 S/cm, respectively, at room temperature. Each of these are higher than the corresponding values reported for complexes of the analogous model compounds or 3-substituted phenothiazine polymer reported earlier.¹³, ²² This was attributed to the very short chain repeat distance for the present, symmetrically substituted polymer.     

New Prospects for the Grafting of Functional Groups onto Aliphatic Polyesters. Ring-Opening Polymerization of α- or γ-Substituted ε-Caprolactone Followed by Chemical Derivatization of the Substituents

Recent progress in the synthesis of aliphatic polyesters, substituted by pendent functional groups, has been reviewed. Two main strategies have to be distinguished. The first route consists of the ring-opening polymerization of ε-caprolactone substituted by various functional groups, protected if needed, in α- or γ-position. In a second strategy, the functional groups are grafted onto preformed polyesters chains in α-position of the carbonyl groups. α-chloro-ε-caprolactone is quite an interesting monomer because, after polymerization, the activated chloride can be easily derivatized by atom transfer radical addition and “click” chemistry, respectively. Similarly, γ-acrylic-ε-caprolactone is precursor of (co)polyesters well-suited to derivatization of the pendent double bonds by Michael addition.     

取代聚苯胺的聚集态结构

环取代基及掺杂对聚苯胺分子链结构产生影响的同时也对大分子聚集态结构产生影响.通过对聚合物膜的XRD、SEM研究，表明在所合成的环取代聚苯胺衍生物中，聚合物的结晶性依POT（聚邻甲苯胺）、PDMAn（聚 2，5 二甲氧基苯胺）、PmClAn（聚间氯苯胺）顺序增加；与本征态的比较，质子酸掺杂后聚合物的结晶性有所提高.POT基本上表现出了非晶聚合物的性质； PDMAn具有同质多晶的结构特征，但结晶度较低； PmClAn表现出了典型高分子晶体性质，符合单斜晶系的特征（晶胞参数为a=0.679 nm， b=2.304 nm， c=0.5734 nm， α=90°， β=100.9°， γ=90°）.采用HyperChem程序包中的MM＋分子力学方法对1H NMR和XRD实验结果进行结构优化，确定了苯式结构/醌式结构为3/2的PmClAn大分子链的构象.     

Synthesis and bulk assembly behavior of linear–dendritic rod diblock copolymers

Dendritic rod structures can be formed via the branching of dendritic elements from a primary polymer backbone; such systems present an opportunity to create nanoscale material structures with highly functional exterior regions. In this work, we report for the first time the synthesis of a hybrid diblock copolymer possessing a linear–dendritic rod architecture. These block copolymers consist of a linear poly(ethylene oxide)–poly(ethylene imine) diblock copolymer around which poly(amido amine) branches have been divergently synthesized from the poly(ethylene imine) block. The dendritic branches are terminated with amine or ester groups for the full generations and half‐generations, respectively; however, the methyl ester terminal groups can also be readily converted into alkyl groups of various lengths, and this allows us to tune the hydrophilic/hydrophobic nature of the dendritic block and, therefore, the amphiphilic properties of the diblock copolymer and its tendencies toward microphase separation. The block copolymers exhibit semicrystallinity due to the presence of the poly(ethylene oxide) block; however, as the polymer fraction consisting of poly(ethylene oxide) decreases, the overall crystallinity also decreases, and it approaches zero at generation 2.0 and higher. The unfunctionalized block copolymers show weak phase segregation in transmission electron microscopy and differential scanning calorimetry at all generations. The addition of n‐alkyl chains increases phase segregation, particularly at high alkyl lengths. The generation 3.5 polymer with n‐dodecyl alkyl substitution has a rodlike or wormlike morphology consisting of domains of 4.1 nm, equivalent to the estimated cross section of the individual polymer chains. In this case, the nanometer scale of the polymer chains can be directly observed with transmission electron microscopy. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2784–2814, 2004