纳米尺度聚合物的分子松弛行为受到了高分子物理学家与材料科学家的关注。然而，基底效应对支撑纳米聚合物薄膜分子松弛行为的影响还存在争议，其本质与传播途径还不清楚。本项目提出基底表面吸附层结构是研究基底效应的突破点，认为基底表面化学、制样条件等首先影响基底表面吸附层结构，再通过吸附层与本体层的重叠区结构达到影响薄膜整体分子松弛行为。项目提出通过设计SiO2基底表面吸附层链结构，研究吸附层PS结构与受限纳米PS薄膜分子运动能力（如玻璃化转变温度、黏度等）、薄膜分子运动能力开始偏离本体的临界厚度的关系，研究吸附层与本体层之间重叠区的厚度、结构与纳米受限薄膜分子运动能力之间的关系。阐明基底效应的本质及基底效应向本体传播的途径，获得衡量基底效应的物理参数。阐明文献报道结果之间存在差异的本质原因。研究成果将为通过控制吸附层结构来调节聚合物超薄膜物理性能的提供理论基础与实验手段。

With the recent advances in nanotechnology, relaxation behaviors of nanometer thick polymer films have attracted great interests of scientists in polymer physics and materials science. Although considerable evidences confirmed the presence of polymer/substrate interface as one of the main factors manipulating the dynamics of supported thin polymer films, the substrate effects on the dynamics of supported ultra-thin films is still an object of intense scientific debate, and how the substrate affect the entire film dynamics remains unclear. Based on our previous researches, we here propose that the nanostructure of the interfacial adsorbed layer is an important breakthrough to investigate the mechanism of the substrate effects, and a new concept of region--- “overlap region” was put forwarded to bridge the gaps between the structures of the adsorbed layer and thin film dynamics. The “overlap region” which is formed due to chain entanglement and interpenetration between the adsorbed layer and the upper bulk region, delivers the interfacial dynamics into the inner bulk of films. All the factors such as the substrate chemistry and film preparation method firstly influence the structure of the adsorbed layer, and the difference in nanostructures of the adsorbed layer further modify the structures and thickness of the “overlap region”, and finally determines the way and depth of the propagation of substrate effect into the bulk. By this route, the dynamics of thin polymer film with tens of nanometer thickness would be impacted by the slight change in the substrate. To validate this mechanism, we fabricated thin polymer film with various nanostructures of the adsorption layer by properly designing the polymer chains structure through incorporating functional groups (e.g. -OH, -COOH) which can interact with the SiOx substrate into the chains, and investigate the correlation between the structure of the adsorbed layer and the glass transition and viscoelasticity of thin polymer films. Also, the relationship between the thickness and structure of “overlap region” and the overall dynamics of thin polymer films will be also explored. The aim of the study is to elucidate the nature of the substrate effects and figure out how the substrate effects propagate into the polymer bulk, and obtain a parameter quantitating the substrate effects on thin film dynamics. These studies would be helpful in reconciling the controversies of results reported by various researcher groups, as well provide experimental method and theoretical basis to design and modulate the physical properties of polymer nanomaterials by controlling the interfacial effects.