高分子在氧化铝纳米孔道中受限结晶的研究进展  

Research Progress on Polymer Crystallization Confined within Nano-porous AAO Templates

作　　者：刘国明[1,2] 施光宇 王笃金 Guo-ming Liu;Guang-yu Shi;Du-jin Wang(CAS Key Laboratory of Engineering Plastics,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190;University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院化学研究所,中国科学院工程塑料重点实验室,北京100190 [2]中国科学院大学,北京100049

出　　处：《高分子学报》2020年第5期501-516,共16页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号21873109,21922308);国家重点研发计划政府间重点专项(项目号2017YFE0117800);中国科学院青年创新促进会(项目号2015026)资助.

摘　　要：高分子材料在微纳米尺度常常表现出不同于本体的物理性质.对结晶性高分子来说,在纳米受限空间的成核机理、结晶结构和动力学特征都与本体材料有所不同.本文总结了近年来基于多孔氧化铝纳米模板(AAO)开展的高分子受限结晶的研究进展,重点介绍了本课题组的工作.研究发现,在AAO模板中,高分子结晶的过冷度大大增加,成核机理从本体的异相成核转变为均相成核或表面成核;高分子结晶结构通常表现为各向异性,动力学因素、热力学因素和界面性质均对取向结构有重要影响;受限情况下高分子结晶速率大大降低,表现出"成核控制"的动力学特征;空间受限使高分子结晶度降低,倾向于形成亚稳态晶型.最后,对该领域尚待解决的问题进行了展望.The crystallization of polymers under nano-confinement has attracted great attention in recent years.Anodic aluminum oxide(AAO) template with uniform nano-cylinders provides an ideal model system for constructing one-dimensional nano-confinement environments. For crystalline polymers under confinement, the nucleation mechanism, crystal orientation, crystallization kinetics, crystallinity, and polymorphic preference are much different from those of the bulk. In the present paper, the research advances on the crystallization mechanism under confinement in AAO templates are summarized with an emphasis on the research results from the authors’ group. The discussions are divided into four sections.(1) Nucleation. There is still a lack of a strict criterion for nucleation mechanism, especially the discrimination between homogeneous and surface nucleation.The frequently reported "multiple nucleation events" prove to result from percolation due to surface residue. The interaction between the polymer and the AAO wall plays an important role in the nucleation of poly(lactic acid).(2) The anisotropic crystalline growth. This section deals with the factors that govern the orientation, including the kinetic selection model, thermodynamic stability, and interfacial interactions.(3) Crystallization kinetics. The Avrami index decreases under confinement. First-order kinetics is observed for polymers within AAO. The Avrami index, that is remarkably smaller than 1, can be explained by the competition growth of multiple nuclei with different growth rates within one pore.(4) Crystallinity and polymorphic preference. The metastable crystalline modifications that are not favored in bulk become more pronounced under confinement within AAO,which provides a method to prepare functional nano-fibers. The questions to be solved on this topic are proposed.

关 键 词：高分子结晶 成核 取向 结晶动力学 纳米受限 

分 类 号：TQ317[化学工程—高聚物工业] TB383.1[一般工业技术—材料科学与工程]