有序多孔膜表面的浸润性转变及其调控研究

Breath figure method is very simple and effective for preparing honeycomb-patterned porous films, which show great potentials in many fields such as superhydrophobic surface, biomaterials, and templating materials. In our previous work, it was found that there exists Cassie-Wenzel wettability transition on polystyrene honeycomb films during layer-by-layer self-assembly (LBL). That means the pores change from non-wetted status to wetted. It is important to investigate what is the critical condition for such wettability transition and how to control the transition. In order to elucidate the critical condition for wettability transition, we proposed to study the effects of surface properties of honeycomb films (e.g., surface hydrophilicity, pore size, area fraction of pores) and the factors of LBL (e.g., solution concentration, assembling time, pH values). Thermodynamics method based on the corresponding model surface will be used to compare with the experimental results. Polyelectrolytes that are relatively hydrophobic will be synthesized and used for LBL self-assembly to delay the wettability transition. Furthermore, polyelectrolytes that are able to response to temperature or ultraviolet will also be synthesized, and the corresponding LBL self-assembly procedure will be optimized to further control the wettability transition. The delayed Cassie-Wenzel wettability transition could result in self-supported polyelectrolyte films that show conformal surface morphology of the honeycomb-patterned porous substrate. This proposed strategy could provide a real surface for investigating wettability transition, and together with investigations on model surface, the interfacial phenomenon of patterned porous polymeric films will be better understood. Taking advantage of the simplicity and efficacy of the breath figure method, this proposed work could be able to provide a new pathway for area-selective surface modification and for preparing patterned polymeric functional films.

呼吸图法作为一种简单高效的图案化方法，制得的有序多孔膜在超疏水表面等诸多领域具有潜在应用价值。申请人在预研工作中发现了有序多孔膜表面的浸润性转变现象，即膜孔从不被浸润向被浸润转变。然而，浸润性转变发生的临界条件以及如何延迟转变尚不清楚。本项目拟从有序多孔膜表面性质(表面亲水性、孔径和孔面积分数等)和层层自组装因素(溶液浓度、组装时间、溶液pH值等)入手，阐明浸润性转变发生的临界条件，并通过热力学模拟进行验证；合成较为疏水的聚电解质，研究浸润性转变的调控规律；合成具有温敏性或光响应性的聚电解质，设计新型组装程序，进一步延迟浸润性转变，获得自支撑聚电解质有序微孔多层膜。本项目研究可望提供一种浸润性转变研究实例，获取有关高分子界面物理化学的新知识；并通过延迟浸润性转变，以有序多孔膜为模板构筑复刻其表面图案的聚电解质有序微孔多层膜，进而建立一种区域选择性的表面修饰新方法和有序功能薄膜的构筑新途径。

呼吸图法作为一种简单高效的图案化方法，制得的有序多孔膜在超疏水表面构筑、精密分离和模板材料等领域具有潜在应用价值。针对有序多孔膜表面的浸润性转变在什么条件下发生以及如何调控等问题，阐述了有序多孔膜表面浸润性转变的条件及其调控规律。首先，系统研究了结构有序、孔径可调、膜表面性能可修饰的有序多孔膜的制备，发现亲水端基对有序多孔膜的形成具有重要影响，强亲水端基可以有效降低膜孔孔径，引入疏水端基则难以形成有序多孔膜。其次，通过研究多巴胺体系在有序多孔膜表面的沉积行为，发现了调控共形沉积的规律，基于浸润性转变构筑的超疏水有序多孔膜表面在液滴粘附、输运、转移等方面展现出独特的性能。最后，初步探索了基于浸润性转变方法制备有序微孔薄膜。本项目研究提供了一种浸润性转变研究实例，建立了一种区域选择性的表面修饰新方法和构筑有序功能薄膜的新途径。