Gurau Marc C, Delongchamp Dean M, Vogel Brandon M, Lin Eric K, Fischer Daniel A, Sambasivan Sharadha, Richter Lee J
Surface and Microanalysis Science Division, Chemical Science and Technology Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8372, Gaithersburg, Maryland 20899, USA.
Langmuir. 2007 Jan 16;23(2):834-42. doi: 10.1021/la0618972.
We measured the molecular order of poly(3-alkylthiophene) chains in thin films before and after melting through the combination of several polarized photon spectroscopies: infrared (IR) absorption, variable angle spectroscopic ellipsometry (SE), and near-edge X-ray absorption fine structure (NEXAFS). The data from the various techniques can be uniformly treated in the context of the dielectric constant tensor epsilon for the film. The combined spectroscopies allow determination of the orientation distribution of the main-chain axis (SE and IR), the conjugated pi system normal (NEXAFS), and the side-chain axis (IR). We find significant improvement in the backbone order of the films after recrystallization of the material at temperatures just below the melting temperature. Less aggressive thermal treatments are less effective. IR studies show that the changes in backbone structure occur without significant alteration of the structure of the alkyl side chains. The data indicate that the side chains exhibit significant disorder for all films regardless of the thermal history of the sample.
红外（IR）吸收、可变角度光谱椭偏仪（SE）和近边X射线吸收精细结构（NEXAFS），测量了聚（3-烷基噻吩）薄膜在熔化前后链的分子有序性。来自各种技术的数据可以在薄膜的介电常数张量ε的背景下进行统一处理。组合光谱能够确定主链轴（SE和IR）、共轭π体系法线（NEXAFS）和侧链轴（IR）的取向分布。我们发现，在略低于熔化温度的温度下对材料进行重结晶后，薄膜的主链有序性有显著改善。不太剧烈的热处理效果较差。红外研究表明，主链结构的变化发生时，烷基侧链的结构没有明显改变。数据表明，无论样品的热历史如何，所有薄膜的侧链都表现出明显的无序性。
