高压下聚苯胺的结构和电性能研究

 以金刚石压腔高压装置为工具，用Ⅱ型金刚石作压砧兼红外窗口，对本征态聚苯胺进行了高压（0~8.4 GPa）就位红外光谱测试。结果表明：在4.8~5.2 GPa压力区间，代表醌环振动的吸收峰相对代表苯环振动的吸收峰变小，表明聚苯胺在此压力区间结构上发生了显著变化，且这种变化是不可逆的。聚苯胺的高压（0~14.5 GPa）电阻测量结果表明：当压力小于7.5 GPa时，电阻随压力升高而显著降低，据此认为聚苯胺为电子性导电物质；在7.5 GPa处电阻出现极小值，然后又缓慢升高，至10 GPa后基本不变。推测聚苯胺电阻极小值是由结构变化引起的。至于红外光谱与电阻测量结果反映聚苯胺结构变化的压力值不一致，可能是由于测试条件不同所致。

STUDY ON POLYANILINE FTIR AND ITS

A Mao-Bell type of diamond anvil cell with Ⅱ-Type Diamond as anvil and infrared window has been used to study in situ Fourier transform infrared (FTIR) spectra of polyaniline under high pressures from 0 to 8.4 GPa. It shows that, between 4.8 and 5.2 GPa, areas of infrared absorption peaks standing for quinoid vibrations decrease compared to those caused by benzenoid vibrations, and this indicates that the structure of polyaniline has changed, and this kind of structural change is inconvertible. Resistance measurements of polyaniline under high pressures between 0 and 14.5 GPa show that resistance reduces dramatically with pressure increasing up to 7.5 GPa, at which a minimum of resistance-pressure curve occurs. These results suggest that polyaniline is a kind of electron conductive material, and its structural change leads to a minimum of resistance.