POSS基含氟杂化聚合物拓扑结构设计与组装有序表面对润湿性能的调控

Polyhedral oligomeric silsesquioxanes (POSS) is a special class of functional nanoscale materials consisting of an eight-corner –(SiO1.5)n-based cage bearing one or more functional groups R as the general formula (RSiO1.5)8. POSS can be incorporated into a polymer matrix by chemical functionalization of one or more functional groups into the corner of the POSS chemical structure. When the functionalized POSS is chemically reacted (via covalent bonds) with the fluoropolymers (FPs) matrix, the resulting POSS-based fluoropolymer (POSS/PFs) could self-assembly into ordered surface of film to control the surface wettability (low surface free energy), thermally stable and reinforced at the molecular level. Therefore, POSS/PFs will become the focus of high performance film materials in the future. However, the coherence between the competively surface migration of POSS cages and the blocks of FPs and the surface wettability is the key point for POSS/PFs hybrids, and few of researches are reported so far. Therefore, this project aims to research the Topology structure design, self-assembly ordered surface and wettability regulation control of POSS-based fluorpolymer hybrids. In this project, different topology structure POSS/PFs hybrids are structured and synthesized; the effluence of self-assembly behaviors and completive surface migration of POSS cages and the blocks in FPs on the well-defined surface is investigated. The regulatory function of self-assembled morphology to the well-defined surface with accumulated fluorinated block and POSS cages is studied; the relationship between the well-defined surface and the wettability of film is explored. Through these researches, the regulation mechanism of topology structures and assembly behaviors to the well-defined surface and wettability is established. It is hoped that the results of this research could provide the scientific basis and technical support to the high-performance fluoropolymer hybrids.

多面体倍半硅氧烷(POSS)具有内核为Si-O-Si骨架笼形结构、外壳连接有机反应性基团R的无机/有机纳米粒子特征，可借R的活性可控聚合引入含氟聚合物(FPs)体系形成POSS基含氟杂化聚合物(POSS/PFs)，通过POSS笼子与PFs嵌段的自组装迁移竞争调控有序结构的非润湿性表面，将会成为杂化聚合物研究的关注焦点。然而，如何利用POSS与PFs表面迁移竞争特征获得有序结构表面以提高非润湿性是POSS/PFs研究的关键所在，至今却尚未见到详细报道。鉴于此，本项目设计并合成两种类型、三种拓扑结构的POSS/FPs、研究POSS/FPs组装行为及POSS与PFs表面迁移竞争对组装有序表面的影响、探明拓扑结构与组装形貌对高含氟量和高POSS含量有序结构表面的调控作用、揭示有序结构表面与POSS/FPs表面润湿性的关系等，为POSS/PFs杂化聚合物材料相关科学问题的研究提供科学依据和技术支持。

项目完成了探明POSS/FPs杂化聚合物拓扑结构与自组装形貌的关系、揭示POSS与FPs迁移竞争表面润湿性能的调控作用、建立POSS/FPs膜层有序结构对润湿性能的影响规律的研究目标。解决了POSS与FPs迁移竞争与拓扑结构的关系、拓扑结构对自组装形貌的调控机制、POSS/FPs涂膜表面有序结构与表面润湿性能的协调作用等关键科学问题。在POSS/FPs杂化聚合物的拓扑结构设计、拓扑结构和溶剂对组装粒子形貌的调控、POSS与FPs迁移竞争对POSS/FPs表面微纳有序结构、化学组成、润湿行为、热稳定性的影响等方面取得重大研究进展。所获得材料在保护砂岩文物的应用和未来国防工业高性能涂层材料等方面实现了突破。.分别设计与合成POSS引发含氟聚合物、POSS封端聚合物、POSS链段与含氟段链聚合物、氟化POSS聚合物、POSS与其它链段的单臂、双臂、四臂、六臂、八臂、十六臂等聚合。研究POSS与FPS含量、链长、连接顺序、化学组成等对聚合物性能的影响。证明了含氟链段表面迁移大于POSS，有利于降低膜表面自由能。16臂结构POSS-(PMMA-b-PDFHM)16与单臂结构ap-POSS-PMMA-b-PDFHM相比，后者成膜时的链段运动更灵活，膜表面粗糙度、氟元素含量、热稳定性等更大。证明了溶剂的介电常数、溶剂与聚合物链段间的相互作用、溶剂挥发速度等对POSS和FPs链段表面迁移驱动力有差异，导致POSS/FPs组装粒子形貌、结构、尺寸大小分布等不仅随拓扑结构发生变化，而且随溶剂而变化。证明了含氟官能团在膜表面定向排布，起到疏水作用，而POSS在膜层中起到支撑膜骨架的作用，使膜层具有一定的硬度。揭示了POSS限制有机链段运动，提高机械强度、热稳定性和机械拉伸模量；POSS与FPs有效结合，防止明显相分离，突出了协同作用。证明了溶剂对POSS和FPs链段表面迁移驱动力有差异，导致膜层结构和膜表面性能随之变化。证明了多臂拓扑结构的POSS/FPs比单臂结构的POSS/FPs具有突出的膜层吸水稳定性。评价了POSS/FPs材料的渗透性、透气性、粘接性、透光性、耐候性、溶剂效应等，解决了长期盲目任意混合使用两种以上保护材料带来的“破坏性保护”问题，在研究方法上实现了突破，提升了我国文物保护材料科技创新能力。