去润湿诱导高分子薄膜的取向与结晶

The properties of polymer thin films are correlated closely with its chain conformation, aggregation structure and surface pattern. Pattern formation by dewetting of polymer thin films is always a focus of people’s concerning, for which a broad range of methods have been developed to control the flow behavior of dewetting, e.g., modifying the substrate with physical or chemical methods and utilizing topographic structure on film surface. However, there are very few studies on understanding dewetting process in molecules scales. Basically, the dewetting process of polymer thin films is a confined flow of viscoelastic fluid with conformational change of polymer chains. Dewetting behavior has an important influence on not only the pattern formation but also structures and properties of the pattern. In this project, we aim to in-situ characterize the structure and morphology evolution during the dewetting and subsequent crystallization process of the low viscosity liquid film or melt film which containing long chain polymer. By the analysis of dewetting process, the following goals are expected to achieve: clarifying the interaction between flow behavior during dewetting process and the flow-induced metastable oriented precursors; understanding the nucleation and crystallization behavior of metastable oriented precursors after dewetting; developing a new method for fabricating nanofiber networks. The research of this project can not only enrich the understanding of the flow-induced nucleation and crystallization, but also provide a novel idea to the regulation of the aggregation structure in polymer surface pattern.

结晶高分子薄膜的性能与其大分子链构象、聚集态结构和表面微图案都密切相关。通过基板改性和薄膜表面引入规则图案控制去润湿宏观流动行为以构筑表面微图案一直是人们关注的重要问题，在分子尺度上对去润湿过程的研究则较少被涉及。实际上，高分子薄膜去润湿过程是伴随有分子链构象变化的粘弹性流体的受限流动，去润湿不仅对薄膜表面图案的形成而且对其本身聚集态结构与性能有着重要影响。本项目拟通过原位表征低黏度长链高分子溶液/熔体薄膜在去润湿及结晶过程中的形貌与结构变化，开展高分子薄膜去润湿过程中大分子链取向有序结构与去润湿行为之间的相互作用关系研究，在此基础上探讨受限条件下不同层次取向有序结构（分子链局部取向到伸展链）的结晶行为，发展通过高分子薄膜去润湿制备与调控纳米取向纤维网络结构的新方法。本项目的研究不仅可以丰富和加深对受限高分子流动诱导成核与结晶的认识，同时也可为高分子薄膜的聚集态结构调控提供新思路。

高分子薄膜去润湿过程是伴随有分子链构象变化的粘弹性流体的受限流动，去润湿不仅对薄膜表面图案的形成而且对其本身聚集态结构与性能有着重要影响。通过原位表征等规聚丙烯超薄膜去润湿过程，开展了结晶高分子薄膜熔融状态与去润湿行为之间的相互作用关系研究，发现熔体有序结构对去润湿流动诱导取向与结晶有明显影响；在此基础上研究了低黏度长链无规聚苯乙烯（aps）溶液薄膜（高低分子量共混）的去润湿行为，探讨受限条件下不同层次取向结构（分子链局部取向到伸展链）演变规律；发展通过高分子薄膜去润湿制备与调控自组装取向有序结构的新方法。以通讯作者发表论文15篇（含Macromolecules 7篇和Polymer 4篇），获授权中国发明专利2项，应邀在国内外学术会议做报告10次。