高分子结晶通常是远离平衡态的过程，折叠链片晶是高分子晶体的基本形态。一般认为片晶的厚度决定其热力学稳定性，而研究表明即使在高分子单晶内部也存在有序程度（亚稳状态）的差异，其形成机制尚未被阐明。此前，人们多采用熔融法研究片晶内微区有序性，但升温过程中伴生的结晶结构完善造成对片晶初始有序差异分辨能力的降低。实际上，片晶的溶解行为也与其聚集态结构密切相关。本项目拟采用溶剂逐步选择性溶解高分子薄膜片晶内部具有不同有序程度的微区，通过改变溶剂类型、溶液浓度、溶解方式、溶解温度与时间，表征溶解过程中片晶形态变化，进一步解析出不同微区的溶解成核诱导期与解吸附活化能等动力学参数，以揭示片晶内微区有序程度与其溶解行为的关系。在此基础上探讨链结构与生长条件对片晶有序差异及分布的影响机制。本项目的研究不仅可以丰富和加深对高分子片晶生长机制的认识，也可为高分子薄膜聚集态结构和图案调控提供新思路。

Polymer crystals usually grow at conditions far away from thermodynamic equilibrium, resulting in lamellae of highly folded chain-like molecules. According to the Gibbs-Thomson relation, the stability of polymer lamella depends on its thickness. Although heterogeneities of metastable state within the solution-grown polymer single crystals have been observed in many past studies, understanding of its formation mechanism is still a challenge. In analogy to archaeology, previous researchers “excavated” the less ordered parts by a controlled and patient annealing procedure, and thereby unveiled the multiple ordered states of a polymer crystal. However, the resolution of initial ordered degree within lamellar crystals will be lower due to the reducing of defect concentration and local thickening during annealing. In fact, the dissolve behavior of polymer lamellae also is associated with the ordered degree of crystalline structure. In this study, heterogeneous ordered structures within lamellar crystals in thin films are revealed by selective dissolution method. Dissolution mechanism of lamellar crystals is studied, as well as the effect of solvent, solution concentration, dissolving method, dissolving temperature and time on lamellar morphology. Parameters of local dissolution kinetics (incubation time of dissolution nucleation and activation energy of molecular detachment) are further analyzed. It is also of fundamental interest in understanding the relationship between dissolution behavior and heterogeneous crystalline structures. Furthermore, the influences of molecular structure and the growth conditions on distribution of heterogeneous ordered region in lamellae are discussed. The research of this project can not only enrich the understanding of the growth mechanism of polymer lamellae, but also provide a novel idea to the regulation of the polymer aggregation structures and surface patterns in thin films.