自掺杂基团对聚苯胺自组装膜电化学性能的影响

基于离子相互作用,实现了以聚苯胺(PANI)为聚阳离子,以聚(邻氨基苯甲酸)(PCAN)、聚(邻氨基苯磺酸)(PSAN)为聚阴离子的层-层自组装,形成层厚均匀的全共轭超薄功能膜.由于磺酸基—SO3-的电负性高于—COO-,使得PANI-PSAN自组装膜沉积量小于PANI-PCAN;电化学实验结果显示,由于PCAN和PSAN的导电性均弱于PANI,所以两种自组装膜的电化学性能取决于PANI,但同时受到羧酸、磺酸基团的较大影响,使得PANI-PCAN自组装膜的电化学性能要优于PANI-PSAN.

EFFECT OF SELF-DOPING GROUPS IN POLYANILINE CHAINS ON THE ELECTROCHEMICAL PROPERTIES OF FULL POLYANILINES SELF-ASSEMBLED FILMS

Full conjugated self-assembled multilayer films from the two polymers,partially doped polyaniline(PANI)as polycation and poly(o-aminobenzoic acid)(PCAN)or poly(aniline-2-sulfonic acid)(PSAN)as polyanion,were fabricated with the layer-by-layer(LBL)technique.The experiments revealed that the UV-Vis absorbance of LBL films increased linearly with the increase of dipping cycle number,which indicated that the amount of polyelectrolyte deposition on the surface of the films in every cycle was uniform.Because sulfonic groups in PSAN had higher electro-negativity than carboxylic groups in PCAN,the molecular chain's stretch and distance among chains were greater than that of PCAN.So the deposition amount of PANI-PSAN in every dipping cycle was less than that of PANI-PCAN in the same condition,which the absorbance of PANI-PSAN film was smaller than that of PANI-PCAN film in the same bilayer number.In conventional three-electrode CV test,the electrochemical properties of the two LBL films mainly depended on pure PANI because the conductibilities of both PCAN and PSAN were weaker than PANI.Compared with PANI-PSAN films,the electrochemical properties of PANI-PCAN films were better due to the effect of deposition.