基于液状PDMS的共价键合型动态双疏表面及其自清洁功能

Fabrication and Self-cleaning Function of Covalently-bonded Dynamically-omniphobic Surface Based on Liquid-like PDMS

目的通过简便的方法在惰性基底上构建具有稳定动态双疏性能和自清洁功能的表面。方法利用非化学计量比的硅橡胶前体表面具有的硅氢键和单乙烯基封端聚二甲基硅氧烷之间的氢化硅烷化反应,在惰性不锈钢基底上制得透明、平滑、无氟、稳定的基于液状PDMS的共价键合型动态双疏表面CBDOS(Covalently-Bonded Dynamically-Omniphobic Surface)。通过ATR-FTIR和XPS表征表面的化学组成,通过AFM和FE-SEM分析表面形貌,通过液滴形状分析仪测定表面的接触角CA值、滑动角SA值和接触角滞后CAH值。结果分析证实液状PDMS已被成功键合在CBDOS表面,且表面具有纳米级粗糙度,均方根粗糙度Rq仅为0.964 nm。同时,表面具有卓越的动态双疏性能和良好的储存稳定性,水的SA值为2.20°、CAH值为1.75°,正十六烷的SA值为7.33°、CAH值为7.34°。这使CBDOS对极性或非极性、相溶或不相溶、水溶性或油溶性的污染物都展现出良好的自清洁功能。结论CBDOS极端均匀平滑的表面形貌及其上单端共价键合的液状PDMS所具有的高度移动性和柔韧性,使其获得卓越的动态双疏性能和自清洁功能。本方法简便,条件温和,对环境无污染,并可拓展应用于各类基底。同时,由于液状PDMS是共价键合在材料表面,可有效增强动态双疏表面的稳定性。

To fabricate a stable surface with dynamic omniphobicity and self-cleaning function on inert substrates,in this paper,a facile approach was developed.The covalently-bonded dynamically-omniphobic surface(CBDOS)was prepared on inert stainless steel substrate by hydrosilylation,which was reacted between the Si-H bond in non-stoichiometry silicone rubber and monovinyl terminated polydimethylsiloxane.CBDOS was transparent,smooth,flouride-free and stable.Then,ATR-FTIR and XPS were used to characterize the chemical composition,which confirmed that liquid-like PDMS had been successfully covalently boned to CBDOS surface.AFM and FE-SEM were used to analyze the surface topography,and the results showed that CBDOS surface considerably smooth with nanoscale roughness.The AFM-derived root mean square roughness(Rq)of CBDOS surface was only 0.964 nm.Drop shape analyzer was used to study the anti-wettability and measure values of contact angle(CA),sliding angle(SA)and contact angle hysteresis(CAH).The water SA and CAH values were 2.20°and 1.75°,and n-hexadecane SA and CAH values were 7.33°and 7.34°,respectively.The data indicated that CBDOS revealed excellent dynamic omniphobicity and well storage stability.Therefore,CBDOS had outstanding self-cleaning function toward many kinds of common contaminants,whether they were polar or non-polar,soluble or insoluble,water-soluble or oil-soluble.It was believed that there were two key factors for CBDOS to realize excellent dynamic omniphobicity and self-cleaning function,one was the extremely homogeneous and smooth surface morphology,the other was the high mobility and flexibility of liquid-like PDMS which was only one end covalently grafted to CBDOS surface.This approach had lots of advantages such as simple operation,mild conditions and non-pollution,in addition,it could be applied to all types of substrates.Furthermore,due to the strategy of covalently bonding,the stability of dynamically omniphobic surfaces based on liquid-like PDMS had been improved distinctly.