原子力显微镜研究高分子超薄膜结晶机理及功能化调控

近十年来,随着功能高分子单晶(含单层或寡层片晶)工程及应用研究的不断深入,除了纳米尺度结晶形貌的表征以外,多功能原子力显微镜还被用于研究分子结构、结晶条件和后处理条件对功能高分子晶体性能(电、热、光、磁等)的影响,进一步还可采用扫描探针加工技术(机械刻蚀、电致刻蚀和热致刻蚀等)对其性能进行调控以构筑功能化聚集态结构和微图案.另一方面,超薄膜中单层或寡层片晶可为研究高分子结晶提供合适的模型体系,与原子力显微镜相结合,不但可以原位、实空间、高分辨地研究高分子的成核与生长过程(生长形态演变和生长动力学),还可以用于研究亚稳态折叠链片晶厚度和形态随热处理温度与时间的演化,从而加深对片晶内有序差异、片晶增厚与熔融行为和自诱导成核的认识.

Atomic Force Microscopy Studies of Polymer Crystallization in Thin Film:Understanding the Formation Mechanism and Tuning the Properties

Over the past decade,besides fundamental concepts,single-crystal engineering of functional polymers and its applications have attracted increasing attention.With the advances of multiparametric and multifunctional characterization,atomic force microscopy(AFM)not only can image the surface topography of polymer crystals in nanoscale while simultaneously mapping the physical properties,like the electrical and thermal properties,but also provides a unique way of linking molecular structures,crystallization conditions and post-treatment to properties.Furthermore,the nanoscale control afforded by scanning probe lithography(SPL)has prompted the development of a regulation of the polymer aggregation structures and surface patterns in thin films.To explicitly probe the mechanism of polymer crystallization,single layer lamella and few layer lamellae in thin films as a model system,combined with AFM can provide information on polymer nucleation and growth with high spatial and temporal resolution.On the other hand,to promote a better understanding of the nature of heterogeneities of metastable state within the lamellae,lamellar thickening/melting and self-seeding,the effects of annealing temperature and time on lamellar thickness of metastable folded-chain crystals have been investigated in polymer thin films.