具有电活性苯胺四聚体接枝聚谷氨酸的合成与表征

以N-羟基琥珀酰亚胺(NHS)活化聚L-谷氨酸的羧基并与苯胺四聚体的氨基缩合,得到了以可生物降解的聚谷氨酸为主链,具有电活性的苯胺四聚体为侧链的新型接枝聚合物.用1H-NMR、质谱分析、光谱分析的方法确定了化合物的结构.侧链羧基的存在使聚合物可以溶解于碱性的缓冲溶液中.对聚合物的电化学性质进行了紫外及循环伏安的表征,研究结果表明,接枝后的聚合物具有与苯胺低聚体相似的可逆的氧化还原过程并可被质子酸掺杂,表现出良好的电化学活性.同时,以定量紫外吸收及元素分析的方法分别测定了聚合物的接枝率.实验中通过控制反应的投料比可以使苯胺四聚体的接枝率达到40%以上,并对聚合物的自掺杂现象进行了讨论.

SYNTHESIS AND CHARACTERIZATION OF ELECTROACTIVE GRAFT COPOLYMER OF POLY(L-GLUTAMIC ACID)-g-ANILINE TETRAMER

Novel electroactive and biodegradable graft copolymers with aniline tetramer side chains were synthesized by conversing the side carboxyl groups of poly(L-glutamic acid) to active N-oxysuccinimide ester,which can be easily substituted by amino compounds.The main chain of grafting copolymer,poly( L-glutamic acid) was recognized as a biodegradable polymer,and the aniline tetramer side chain,which is similar with polyaniline in electrical chemical properties,enabled the copolymer to gain or lose electron reversibly,i.e.electroactivity.The chemical structures of the copolymers were confirmed by 1H-NMR,UV-Vis spectrum and elemental analysis.The copolymer can be dissolved in DMF,DMSO or alkaline aqueous solution.The UV-Vis spectrum of the copolymer was measured in DMF at different buffer pH values.The aniline tetramer side chain can be oxided to its emeraldine state in the presence of oxidant and doped by protonic acid.The cyclic voltammogram of the copolymer,measured in 1 mol /L HCl aqueous solution,showed that there were two pairs of reversible redox peaks,which correspond to two redox processes.These characters indicated that the graft copolymer showed a good electroactivity.The graft ratio of aniline tetramer was confirmed by both element analysis method and quantitative UV absorbance of the copolymer in its leucoemeraldine state.The graft ratio could reach to upon 40% by appropriate feed ratio,which meant a higher weight percentage of electroactive units compared with those block copolymers previously reported.A new route to build both electroactive and biodegradable polymers was reported,which may have potential application in nerve tissue engineering and some other aspects of biological researches.