Functional Polymeric Thin Films with High Molecular Ordered Structure Along Molecular Chain and Side Chain Directions

气相沉积聚合（VDP）是一种有用且有前途的功能聚合物薄膜制备方法，如具有高热稳定性的聚酰亚胺薄膜和具有压电性和热电性的聚脲薄膜。与Langmuir-Blodgett （LB）法和其他聚合物薄膜的制备方法相比，VDP具有很大的优势，因为该方法是一种简单的干燥过程。此外，VDP薄膜中的分子取向可以被控制。例如，VDP方法可以产生垂直于衬底表面的高分子取向的聚酰胺和聚酰亚胺薄膜。本文研究了一种交替层间缩聚（AVDP）的基本思想，以获得超高分子取向和多尼龙体系，如尼龙-mn和尼龙-mnop的延伸链构象。在尼龙体系的AVDP工艺中，两种双功能单体，如二氯单体（DC）和二胺单体（DA）交替沉积在衬底上。首先，DC被沉积在氨基覆盖的底物上。所得尼龙薄膜具有高度有序的结构，其分子取向与衬底垂直。随着沉积次数的增加，尼龙膜的厚度和分子量呈线性增加。换句话说，薄膜厚度可以通过反应循环次数来控制。尼龙-66薄膜的分子量与薄膜厚度成正比。这一结果清楚地表明，薄膜厚度的增加是由于基板表面的链延伸过程而没有链折叠。

Vapor deposition polymerization (VDP) is a useful and promising method for fabrication of functional polymeric thin films, such as polyimide thin films with high thermal stability and polyurea films having piezoelectricity and pyro-electricity. Compared with the Langmuir-Blodgett (LB) method and other preparation methods of polymeric thin films, VDP has a great advantage because the method is a simple dry process. In addition, molecular orientation in a VDP film can be controlled. For example, the VDP method can produce polyamide and polyimide films with high molecular orientation perpendicular to the substrate surface. The present work deals with a basic idea of the alternating layer-by-layer poly-condensation (AVDP) to get an ultra-high molecular orientation and a multi-nylon system, such as a nylon-mn and nylon-mnop with the extended chain conformation. In the AVDP process of nylon systems, two kinds of bifunctional monomers, such as a dichloride monomer (DC) and a diamine monomer (DA) are deposited alternately onto a substrate. At first, DC is deposited onto the amino covered substrate. The resultant nylon films show the highly ordered structure with the molecular orientation normal to the substrate. The thickness and the molecular weight for the nylon film increase linearly with the number of deposition cycles. In other words, the film thickness can be controlled by the number of reaction cycles. The molecular weight of nylon-66 film is proportional to the film thickness. This result clearly indicates that the increase in the thickness of the film is due to a chain-extending process from the substrate surface without a chain folding.