POSS-氟丙烯酸酯-聚硅氧烷共聚物微结构调控及低温防冰性能

Icing phenomena often appear on equipments of power transmission, ships and aircrafts at low temperatures and high humidity. Sometimes, ice adhesion and accumulation on solid surfaces can cause troubles or damages. Generally, de-icing by mechanically removing, heating or spraying chemicals can cause energy consumptions or environment pollutions. Therefore, anti-icing by inherent properties of the coating on substances is of great importance. In this project, we propose a novel method to prepare anti-icing coating based on polyhedral oligomeric silsesquioxane (POSS)-fluoroalkyl acrylate-polysiloxane copolymers, and explore the relationships between the surface structure and properties of the copolymer coatings for anti-icing..It has been proved that icephobic or superhydrophobic coatings containing fluorine and silicone with low surface energy can be used for anti-icing by shortening the attaching time of water drops on the substrate and reducing the ice adhesion strength. However, improvement in durability of the icephobic and superhydrophobic coatings is still required, and the relationship between the surface structure, properties and icing process as well as the subsequent ice building up on the coating surface is not clearly understood. Therefore, it is necessary to carry out scientific researches in this topic so as to develop anti-icing coatings with excellent properties..By means of reversible addition-fragmentation chain transfer (RAFT), one of controlled/living radical polymerization methods, well-defined graft poly(dimethylsiloxane) (PDMS) copolymers can be prepared from macromonomers, while macroinitiators or macro-chain transfer agents provide a suitable way to synthesize block copolymers. In the present project, a series of tailored POSS-fluoroalkyl (meth)acrylate-polysiloxane block and graft copolymers will be synthesized with the aid of macromonomers or macroinitiators via RAFT process. Coatings with stably regular patterns and superhydrophobicity will be constructed based on microphase separation of the copolymers, which is generated by self-assembly of soft and hard segments in certain solvents and synergistic effect between fluorine and silicone segments. Functional monomers including methacrylate PDMS, methacrylate POSS, fluoroalkyl (meth)acylates, etc. will be specifically used for syntheses, and macroinitiators (PDMS macro-azo-initiators) and macro-RAFT agents (eg. trithiocarbonate terminated PDMS) will be employed to modulate the length, amount and spacing distribution of the PDMS segment in the block and graft copolymers. The molecular weight and glass transition temperature of the copolymers will also be controlled. Tunable strategies in the copolymer microstructure as well as the effect of surface topography and properties on ice formation and accretion at low temperatures (-20℃~0℃) will be focused. Finally, it is expected to provide a novel concept in the fundamental relationships between the copolymer surface and icing.

结冰会给人类和社会带来危害，加热防冰等方式耗能大，因此研究低温防结冰材料非常重要。含氟/硅的疏冰和超疏水涂层是当前研究热点，但其长效性和稳定性还存在问题，而涂层表面与结冰之间的关系目前尚未完全明了。本项目拟以POSS-氟丙烯酸酯-聚硅氧烷的嵌段和接枝共聚物为研究对象，通过软硬链段自组装和氟硅链段协同作用构建有序化稳定结构的超疏水涂层。以RAFT聚合原理，由功能单体(PDMS-MA、POSS-MA、FMA)、大分子引发剂(PDMS-azo)及链转移剂(PDMS-TTC等)，设计合成一系列不同组成、不同侧链和主链结构的POSS-氟(甲基)丙烯酸酯-聚硅氧烷共聚物，研究所合成的共聚物分子量、聚硅氧烷链段长度、数量及空间分布和POSS及氟含量对共聚物微相分离结构的调控机制，并研究由此形成的涂层表面性能和拓扑结构在低温(-20℃至0℃)下与冰的粘附及积累的关系，开拓防结冰材料研究的新思路和新方法。

低温下冰在飞机和基础设施表面的附着和累积会给人类生活带来严重的安全隐患，低表面能涂层可以降低冰与涂层间的作用力，能起到较好的防覆冰效果。本项目结合多面体低聚倍半硅氧烷(POSS)、有机硅和含氟材料在防覆冰涂层方面的优点，分别采用大分子引发剂、可逆加成-断裂链转移聚合以及硅氢加成方法合成了一系列不同化学结构的氟硅共聚物，并在一定条件下固化形成涂层。对共聚物及其涂层的化学组成、表面形貌和润湿性对防覆冰性能的影响进行了系统研究。结果表明，嵌段共聚物涂层表面具有微相分离结构，POSS和氟硅协同效应可提高涂层的疏水性和防覆冰性能。以八乙烯基POSS为交联剂制备的氟硅改性聚甲基丙烯酸酯共聚物光固化涂层，具有较大的后退角，可以使过冷水滴弹离涂层表面，有效地抑制涂层表面的覆冰。氟硅改性聚丙烯酸酯涂层的冰剪切强度最低达100-300kPa，引入POSS后可提高其防覆冰性能的稳定性，而基于氟烷基改性的聚二甲基硅氧烷(PDMS)涂层可进一步降低冰剪切强度至100kPa以下，以氟化POSS为共交联剂形成的油润滑性PDMS涂层，其冰剪切强度可进一步降低至20kPa以下。总体而言，超疏水涂层在一定条件下可起到防覆冰作用，但其在低温潮湿条件下易失去其超疏水优势，故本项目着重对低表面能的疏冰涂层和润滑性涂层进行了详细研究。. 本项目执行期间，项目组已在Progress in Organic Coatings, Applied Surface Science, RSC Advances, Chinese Journal of Polymer Science等SCI收录期刊上正式发表研究论文10篇、综述论文2篇，申请国家发明专利8项，授权专利4项，其中1项正在申请国际PCT保护。