Confinement effects on the molecular dynamics of polymers with special architectures

研究具有特殊结构的聚合物(即树枝状聚合物)薄膜中分子动力学的限制效应具有双重动机。在技术上，这些材料具有潜在的应用前景，据报道，人们对将它们用作薄膜特别感兴趣。因此，这个项目的目的是为了促进对聚合物体系动力学中大分子结构作用的基本理解。重点研究了禁闭引起的动态玻璃化转变与其本体行为的偏差。这方面涉及两个方面：(I)大分子结构在受限聚合物的动力学中扮演什么角色；(Ii)当应用于薄膜时，研究玻璃化转变的不同方法在多大程度上提供了可比较的结果。具有不同支化结构的聚合物体系将被合成、修饰、表征并进一步用于薄膜的制备。它们的物理结构和化学成分、表面形态、折射率、表面性质(表面能和电荷、润湿性)将取决于薄膜厚度。利用宽带介电谱、膨胀仪、交流量热仪、椭圆偏振光谱仪和红外光谱(FTIR)等辅助测量手段，研究了限制效应对超支化聚合物薄膜动力学的影响。

There is a twofold motivation to investigate confinement effects on the molecular dynamics in thin films of polymers having special architectures, i.e. dendritic polymers. Technologically, these materials promise potential applications, a special interest being reported to use them as thin films. Concomitantly, this project is intended to contribute to the basic understanding of the role of the macromolecular architecture in the dynamics of polymeric systems. A special emphasis is put on the investigation of the confinement-induced deviations of the dynamic glass transition from its bulk behaviour. Two aspects are addressed in this respect: (i) what role plays the macromolecular architecture in the dynamics of confined polymers; (ii) to what extent different methods to investigate the glass transition provide comparable results when applied to thin films. Polymeric systems having different branched architectures will be synthesized, modified, characterised and used, further, for the preparation of thin films. Their physical structure and chemical composition, surface morphology, refractive index, surface properties (surface energy and charge, wetting) will be examined in dependence on the film thickness. Complementary measurements by Broadband Dielectric Spectroscopy, dilatometry, AC-calorimetry, spectroscopic ellipsometry and temperature dependent Fourier Transform Infra-red Spectroscopy (FTIR) will be carried-out to investigate the confinement effects on the dynamics of hyperbranched polymers in thin films.