本征型自修复聚硅氧烷材料:从单重动态交联网络到多重动态交联网络

Intrinsic Self-healing Polysiloxane Materials:From Single Dynamic Crosslinked Network to Multiple Dynamic Crosslinked Networks

近年来,本征型自修复聚硅氧烷材料因兼具聚硅氧烷的优异性能和损伤自修复功能,在复合材料、智能涂层、柔性器件等领域显示出巨大的应用潜能.本征型自修复聚硅氧烷材料主要通过在聚硅氧烷交联网络中引入各种动态非共价键和动态共价键,借助动态键的可逆断裂与重组来重排交联网络而实现损伤修复.迄今为止,已有数十种修复机制或体系被相继报道,但仍存在自修复能力与力学性能间的矛盾.为解决这一根本问题,聚硅氧烷材料的动态交联网络正从单重动态交联向多重动态交联转变,并结合结晶或取向等工艺以及通过与改性纳米粒子复合,这些方法对自修复材料的力学性能和自修复能力的协同调控都有着重要影响.鉴于此,本文根据本征型自修复聚硅氧烷材料中动态键和动态交联网络的结构差异,对其动态交联网络的结构设计、自修复机制、性能调控以及应用研究等方面进行了综述分析,并展望了本征型自修复聚硅氧烷材料未来的发展方向.

Recently,intrinsic self-healing polysiloxane materials owing to the excellent performances of silicone materials like resistance to high/low temperature,electrical insulation,hydrophobicity and biocompatibility,and novel self-healing ability to damages,have shown great potential in smart coatings,sensors,flexible devices and other fields.Intrinsic self-healing polysiloxane materials are mainly constructed by introducing dynamic non covalent bonds(hydrogen bond,metal-ligand coordination interaction,ionic bond,etc.)or/and dynamic covalent bonds(Diels-Alder bond,imine bond,boronic ester bond,siloxane bond,disulphide bond,etc.)into their crosslinked networks.These dynamic bonds can be reversibly dissociated and recombined under moderate external stimuli,which thus enable the polymers to repair damage and restore functions.To date,dozens of self healing mechanisms or systems for polysiloxane materials have been reported,but there is still a great challenge between excellent self-healing ability and high mechanical strengths.To address this fundamental issue,the crosslinked network of polysiloxane materials is converted from single dynamic bond to multiple dynamic bonds.The synergetic combination of dynamic covalent bond and non-covalent bond plays an important role in the efficient regulation of mechanical performances and self-healing capacities.Besides,the orientation,crystallization or phase separation of polymer chains is also considered as an effective way to improve the comprehensive properties of self-healing polysiloxane materials,because it can compensate for the reduction of mechanical properties to a certain extent.Moreover,the compositing polysiloxane materials with diverse nano fillers grafted with dynamic bonds not only improve their comprehensive performances but also give new functions such as electric conduction,sensing,heat conduction.In view of this,this paper will review the network structure design,self-healing mechanism,property regulation and potential applications of intrinsic self-healing polysiloxane materials,based on their structural differences of dynamic bonds and dynamic crosslinked networks.Finally,an outlook on the future development of intrinsic self-healing polysiloxane materials is prospected.