Electric Birefringence Relaxation Spectroscopy of Electroactive Polymer Solutions

用He-Ne激光或Ar离子激光等可见光光源很难测量具有共轭电子的电活性聚合物溶液的电双折射弛豫，因为此类聚合物通常在可见光范围内有很强的吸收带。在这项研究中，我们利用高功率半导体激光器作为近红外光源，研制了一台高精度、宽带的电双折射弛豫光谱仪，使我们能够在很短的时间内探测到聚合物的总弛豫谱。取得的结果如下：1.研究结果。研制了一种高稳定、高功率的半导体激光光源系统。通过将该光源与高速、高分辨率的暂态存储器和个人计算机相结合，我们实现了高精度的实时电双折射弛豫谱仪。利用这台光谱仪，我们测量了典型的电活性聚合物如聚二乙炔和聚噻吩在好的和差的溶剂中的电双折射弛豫谱，得到了关于聚合物构象(棒状或随机盘绕)以及聚合物中的电极化机制(定域载流子引起的永久偶极矩的取向极化或非定域载流子引起的激发极化)的信息，即关于带电载流子在聚合物中的迁移率的信息。

It is difficult to measure the electric birefringence relaxation of solutions of electroactive polymers with conjugated electrons by using a visible light source such as a He-Ne laser or Ar ion laser, because such polymers usually have strong absorption bands in visible light range. In this study, by utilizing a high-power semiconductor laser as a near-infrared light source, we have developed a high-accuracy, broadband electric birefringence relaxation spectrometer which enables us to detect a total profile of relaxational spectra of the polymers in a very short time. The results obtained are as follows.1. A semiconductor laser light source system with high stability and high power has been developed. By combining this light source with a high-speed, high-resolution transient memory and a personal computer, we have realized a high-accuracy realtime electric birefringence relaxation spectrometer.2. By use of this spectrometer, we have measured the electric birefringence relaxation spectra of typical electroactive polymers such as polydiacetylene and polythiophene in good and poor solvents, and obtained information on the polymer conformation (rodlike or randomly coiled) as well as on the electric polarization mechanism in the polymers (orientational polarization of permanent dipole moment arising from localized carriers or induced polarization due to unlocalized carriers), in other words, on the mobility of charged carriers in the polymers.