Quantitative Evaluation of Crystalline Defects in Langmuir-Blodgett Film

本文研究了单层膜和朗缪尔-布洛吉特(LB膜)膜中晶体缺陷的定量评价以及低晶体缺陷的制备。根据静态粘弹性的亚相温度、TSP依赖性与其聚集结构的关系，估算了脂肪酸单分子膜在水表面的熔融温度Tm和结晶松弛温度Tc。结果表明，单分子膜的表面压力-面积等温线代表了孤立微区的聚集过程，这些孤立微区是在扩散到水面后立即形成的。根据TM与TSP的关系，可将单分子膜分为晶态膜和非晶态膜。在电子衍射技术的基础上，对单层膜中的晶体缺陷D进行了表征。与结晶单分子膜(D=4%)相比，由非晶态分子在水面结晶得到的结晶单分子膜具有很低的结晶缺陷值(D=1.5%)。另一方面，利用X射线衍射仪对LB膜中的晶格缺陷进行了分析。结果表明，LB膜中的晶格缺陷受制备条件的控制。这些结果对制备无晶格缺陷的LB膜具有重要的指导意义。

In this study, the quantitative evaluation of crystalline defects in monolayer and langmuir-blodgett (LB) film and the preparation of them with low crystalline defects were investigated. The melting temperature, Tm and crystalline relaxation one, T c of fatty acid monolayers on the water surface was evaluated from the relationships between the subphase temperature, Tsp dependence of static viscoelasticities and the aggregation structure of them. It was made clear that the surface pressure-area isotherm of monolayer represented the gathering process of isolated domains, which were formed right after spreading on the water surface. From the relationship between Tm and Tsp, the monolayers were classified into the crystalline one and the amorphous one. On the basis of electron diffraction technique, the crystalline defects, D in monolayer were evaluated. In comparison with crystalline monolayer (D = 4 %), the crystallized monolayer, which was obtained by the crystallization of amorphous one on the water surface, had very low value of crystalline defects (D = 1.5 %). On the other hand, the crystalline defects in LB film were evaluated on the basis of X-ray diffraction technique. It became clear that the crystalline defects in LB film were controlled by the condition of preparation. These results should be very useful for preparation of the LB film with no crystalline defect.