变温拉曼光谱研究电化学合成聚吡咯膜

Raman Spectroscopic Study on Electrosynthesized Polypyrrole Films During Heating and Cooling Processes

在含有四氟化硼四丁基铵的乙氰溶液中电化学氧化吡咯制得聚吡咯膜,并在-195到150℃温度范围内研究了该聚合物膜的变温拉曼光谱。在升温过程中,与氧化态相关的拉曼光谱谱带渐渐消失,这主要是由于空气中氧气和水分子的作用。在冷冻过程中,聚合物链从无规线团状态转变成棒状构象,从而增加了导电高分子的共轭链长。由于拉曼的共振效应,在冷冻过程中与氧化态链段相关的谱带得到了增强。

Polypyrrole films have been electrochemically synthesized by direct oxidative polymerization of pyrrole in acetonitrile containing tetrabutylammonium tetrafluoroborate as supporting electrolyte. We characterized the as-grown polypyrrole films by resonance Raman spectroscopy in the temperature scale of -195 to 150 ℃. During the heating process, The Raman bands related to the oxidized species decreased gradually, mainly due to the effects of oxygen and moisture in air. During the cooling process, polymer chains changed from disordered (coil-like) to ordered (rod-like) structures and caused the elongation of conjugated chain length. This led the enhancements of the Raman bands related to the oxidized species.