利用共聚物在纺丝液中的自组装调控纳米纤维的微纳有序结构

Using self-assembly of copolymer or phase separation of polymer blend for preparation of materials with ordered micro/nano structure have attracted many attentions in recent years. The ordered micro/nano structure haver very important influence on the properties and function of the polymeric materials. However, most of researches on this area are focused on the 3-dimensional bulk material or 2-dimensional film. A few researches were reported for preparation 1-dimensional fiber especially nanofiber with ordered micro/nano structure by electrospinning, which have widely potential applications in many field such as chemical or biologic molecular probes, tissue engineering scaffolds, controlled drug release, and selective filtration materials. For nanofibers prepared from electrospinning, owing to the fast evaporation of solvent and elongation of jet during electrospinning, it is very hard to control the phase structure. It still remains a great challenge to construct nanofibers with ordered micro/nano structures by facile and low-cost solution-phase protocols. To address this issue, in this work, nano aggregates self-assemblied in spinning solution will be blended with the homopolymer of solventphilic segment of the copolymer for preparing electrospun nanofiber. The preformed ordered structure from self-assembly could be preserved and directionally evolved during electrospinning. Therefore, the ordered micro/nano structure in nanofibers could be effectively regulated by the shape, size, and structure of the nano self-assembly. After systematic researches on the structures, morphologies, properties of the nano self-assembly and nanofiber, and their relationships, the formation mechanism of the nanofibers with ordered micro/nano structure from the nano self-assembly in spinning solution will be proposed. This research will provide not only novel preparation strategy for this research area, but also a theoretical fundament for potential functional application of this kind of nanofibers.

通过高分子共聚物的自组装或共混物的相分离诱导获得具有微纳尺度有序结构的材料是近年来研究的一个热点领域。然而对于静电纺丝的纳米纤维来说，由于纺丝过程中射流拉伸和溶剂快速挥发等因素使得要实现纤维中有序结构的有效调控变得较为困难。本研究拟通过高分子共聚物在纺丝液中预先的自组装形成纳米自组装体，然后与其亲溶剂链段的均聚物共混静电纺丝的方法来解决这一问题。这种由自组装预先形成的有序结构在静电纺丝过程中可以得到充分的保留和定向的演变。通过改变纺丝液中纳米自组装体形貌、尺寸、结构等因素，即可实现对所获纳米纤维中微纳有序结构的有效调控。系统研究纳米自组装体和纳米纤维的结构、形貌和性能，详细了解二者之间的内在联系，提出通过共聚物自组装调控纳米纤维有序结构的理论模型和机理。通过以上研究，可以为聚合物纳米材料有序结构的调控提供新的思路和方法，也可以为拓展聚合物纳米纤维材料的功能化应用提供理论基础。

本项目研究目标为通过聚合物/共聚物自身或与纳米粒子在纺丝液/溶液中预先的自组装形成纳米自组装体，进而通过静电纺丝、流延成膜等方法制备具有可控微纳有序结构的纳米复合纤维/膜，揭示微纳有序结构及性能之间的内在联系，并探索其在相关领域的实际应用。在获得国家自然科学基金资助后，成功地利用共聚物及其与各向异性纳米粒子自组装过程构筑了一系列具有微纳有序结构的聚合物纳米复合纤维/膜，系统研究了制样条件、自组装行为等对复合纤维/膜结构与性能的影响，提出了对微纳结构调控的机理。利用各向异性自组装聚集体在静电纺丝过程中的取向与聚集实现了对纳米纤维相结构的调控；通过端基芘修饰的共聚物与碳基纳米粒子的自组装在聚合物基体中构建了具有很低逾渗值的碳基纳米粒子导电网络；制备了具有光/热双重自修复的可回收纳米复合材料；利用静电相互作用诱导制备了杂化纳米聚集体并用于调控纳米复合膜中的微纳有序结构，有效改善了复合膜的氧气阻隔性、抗菌性和力学性能；此外还采用甲壳素纳米微晶作为增强体和共交联枢纽，在静电纺丝所得的纳米纤维中构建了化学网络结构，从而大大提高了静纺纳米纤维膜在长时间分离过程中的结构稳定性，并用于高效的油水乳液分离应用。研究取得了理想的实验结果，达到了研究目的，完成了计划书的目标。.本项目共发表SCI收录论文10篇（第一标注8篇、第二标注2篇），其中影响因子3.0以上的7篇，影响因子8.0以上的2篇；申请中国发明专利2项。参加重要国际会议5次，并发表口头报告；在项目支持下，除了指导项目负责人自己的研究生，还与所在课题组其他教师合作研究和培养研究生，共培养了1名博士研究生，6名硕士研究生，均已获得相应学位。以上成果均已达到或超过了预期研究目标。