Induction current of conducting polymers in magnetic field

我们发现导电态的聚苯胺薄膜在磁场中会产生感应电流。当膜是电阻性的时，未检测到电流。由于它在渗流阈值电位处逐步增加，因此不能用洛伦兹力的普通磁效应来解释。这可能是由导电状态的分子线圈引起的，其感应电流随磁场强度、磁场频率、薄膜厚度、掺杂浓度和溶液pH值的变化而变化。这似乎与导电畴的宏观尺寸有关。作为磁场效应的延伸，我们开发了散射光的测量，以确定宏观畴的大小。用可见光照射聚苯胺薄膜，测量了其散射光强度随散射角的变化。散射光不是由罗利散射引起的，而是由干涉引起的。通过对光强随角度变化的分析，我们发现了直径为5 μ m的导电团簇的存在，这些团簇可以用显微镜观察到。随着时间的延长，纳米颗粒的尺寸逐渐增大，其尺寸与时间的对数呈线性关系。

We found that a polyaniline film in the electrically conducting state induced current when it was in magnetic field. The current was not detected when the film was resistive. Since it increased stepwise at a percolation threshold potential, it cannot be explained by ordinary magnetic effects by Lorentz force. It may be caused by molecular coils of the conducting state.The induced current varied with intensity with the magnetic field, the magnetic frequency, thickness of the film, a doping level, and pH of the solution. It seems to be related with a macroscopic size of conducting domains. As an extension of the magnetic field effect, we developed measurements of scattering light in order to determine the size of the macroscopic domains. A visible laser was shone on the potentiostated polyaniline films, and the scattering light intensity was detected as a function of scattering angles. The scattering light was not due to Raleigh scattering but included interference, By the analysis of variaqtion of the light intensity with the angles, we found the presence of conducting clusters 5 mum in diamter, which could be detcted through a microscope. The size increased with a time of potential application, showing a linear variation of the size with the logarithmic time.