聚合物垂直通孔膜的定向结晶模板法制备与应用基础研究

Polymer membranes with well-controlled and vertically-oriented pores have exerted a tremendous fascination on academia and industries, due to their potential applications for precise separation, forward osmosis and lithium ion batteries. Although plenty of fabricating techniques have been reported, the large-scale application of such membranes are greatly hampered by the complicated preparation procedures such as breath figure, limited polymer types, and lack of methods for precisely manipulating pore size, density and morphology. In this project, we propose an environmental-friendly facile fabrication of these membranes on the basis of bidirectional freezing technique. Solvents with high melting points will be adopted as crystal templates for vertically-oriented pores from a broad spectrum of polymer resources, based on the solubility parameter theory. We will systematically investigate the directional crystallization behaviors of solvents in the polymer matrices, based on the analysis of the interaction between polymer and solvent experimentally and mathematically. Then detailed investigations will be conducted on the roles of polymer concentration, cooling temperature, nucleation density and additives in manipulating pore size, density and shape. Finally, the fabricated polymer membranes with well-controlled and vertically-oriented pores are expected to be used for precise separation, support layer for forward osmosis, and lithium ion battery separators.

聚合物垂直通孔膜可望在精细分离、正渗透盐差发电和锂离子电池等诸多领域得到广泛的应用，但迄今为止，呼吸图法等聚合物垂直通孔膜的制备方法仍存在适用聚合物范围窄、步骤繁琐、成本高等问题，制备的分离膜的孔密度远低于常规的相转化法，无法精确调控垂直通孔膜的孔径、密度与孔结构，从而限制了规模化制备的实现与应用。研究和发展一种简单方便、可规模化制备聚合物垂直通孔膜的普适性方法，已成为膜科学领域一个亟待解决的关键科学问题。本课题提出以高熔点溶剂晶体为模板，发展取向冷冻技术，实现聚合物垂直通孔膜的普适化制备；系统考察一系列聚合物/结晶性溶剂体系的取向结晶行为，组合实验手段和模拟计算分析聚合物和溶剂晶体之间的相互作用，揭示聚合物高粘度体系对溶剂定向结晶的影响规律，以溶剂结晶成核密度和晶体生长动力学为基础建立膜孔大小、密度和形状的精细调控方法，为制备性能优异、结构可控的聚合物垂直通孔膜提供理论指导和技术基础。

聚合物通孔膜可望在精细分离、正渗透盐差发电和锂离子电池等诸多领域得到广泛的应用，但迄今为止，呼吸图法等聚合物垂直通孔膜的制备方法仍存在适用聚合物范围窄、步骤繁琐、成本高等问题，制备的分离膜的孔密度远低于常规的相转化法，无法精确调控垂直通孔膜的孔径、密度与孔结构，从而限制了规模化制备的实现与应用。研究和发展一种简单方便、可规模化制备聚合物垂直通孔膜的普适性方法，已成为膜科学领域一个亟待解决的关键科学问题。本研究以高熔点溶剂晶体为模板，组合双向冷冻与热致相分离技术，突破了聚合物通孔膜的普适化化制备，直通孔的角度从25度到90度可调；系统考察了一系列聚合物/结晶性溶剂体系的取向结晶行为，组合实验手段和模拟计算分析了聚合物和溶剂晶体之间的相互作用，初步揭示了聚合物分子量对溶剂定向结晶的影响规律，以溶剂结晶成核密度和晶体生长动力学为基础发展了膜孔大小、膜孔密度和膜孔形状等的调控方法，支撑了性能优异、结构可控的聚合物通孔膜的制备技术基础。所制备的通孔膜在水体快速去除微塑料、高通量正渗透、原油/水混合物分离、光热转换海水淡化、锂离子电池隔膜等领域均显示出潜在的应用前景。相关结果发表高质量论文10篇、培养博士研究生2名、硕士研究生3名，出站博士后1名。