形状记忆环氧树脂/聚二甲基硅氧烷@ZnO@SiO_(2)自修复超疏水涂层及其防腐性能

Self-healing superhydrophobic shape memory epoxy resin/polydimethylsiloxane@ZnO@SiO_(2) coating and its anticorrosion performance

本文针对环氧树脂基类超疏水防腐涂层的物理损伤修复速度较慢,并结合不锈钢金属长期处于高湿高盐等环境下高效防腐与保护的实际应用需求,以微晶蜡强化的形状记忆环氧树脂涂层(SMEP)为底层,以超疏水材料聚二甲基硅氧烷(PDMS)@ZnO@SiO_(2)(PZS)为表层,基于双层设计制备了一种较快修复机械损伤、不锈钢持久防腐的自修复超疏水涂层SMEP/PDMS@ZnO@SiO_(2)(SMEP/PZS),并着重对其修复前后SMEP/PZS涂层的润湿性、耐蚀性及其自修复与防腐机制等进行了深入探讨。结果表明,SMEP/PZS涂层具有良好的超疏水性及自清洁等相关性能,其超疏水性随着低表面能物质全氟癸基三甲氧基硅烷(PFDTMS)含量增加而增强,水接触角、滚动角最佳可达157.6°和2.6°。其次,SMEP/PZS涂层有较快的自修复能力,将该机械模拟的受损涂层于85℃下在20 min较短时间内进行修复,其最佳机械划痕由45µm缩小至1.0µm,修复率达97.8%。此外,SMEP/PZS涂层表现良好的耐蚀性,且将修复后的该涂层置于3.5wt%NaCl溶液中浸泡14天后,其耐腐蚀性接近于原始涂层。将SMEP/PZS涂层涂覆在不锈钢基底上,在3.5wt%NaCl溶液中所测点蚀电位Eb与裸不锈钢的相比正移近10倍,维钝电流密度Ip下降2个数量级,对304不锈钢基底具有相对更为持久的防腐与保护。最后,进一步探讨了SMEP/PZS涂层的自修复与防腐蚀机制。

In this paper,based on the two-layer design,a self-healing superhydrophobic coating self-healing shape memory epoxy resin(SMEP)/polydimethylsiloxane(PDMS)@ZnO@SiO_(2)(SMEP/PZS)that could quickly repair physical damages and durably corrosion resistance of stainless steel was prepared.Aiming to solve the slow physical damage repair of epoxy-based superhydrophobic anti-corrosion coatings,and inegrate with the practical application requirements of high efficiency anticorrosion and protection of stainless steel in high humidity and high salt environment for a long time.The double-layer coating was designed by combination of a SMEP and a superhydrophobic material PDMS@ZnO@SiO_(2)(PZS).Furthermore,the wettability,corrosion resistance,self-healing and corrosion resistance mechanism of SMEP/PZS coating before and after repairing were discussed in detail.The results show that SMEP/PZS coating has excellent superhydrophobicity and self-cleaning properties,and its superhydrophobicity increases with the increase of perfluorodecyltrimethoxysilane(PFDTMS)content,its optimal water contact angle and rolling angle are 157.6°and 2.6°.Secondly,SMEP/PZS coating has a faster self-healing ability,the best mechanical scratches of SMEP/PZS coating are reduced from 45µm to 1.0µm in a shorter time of 20 min at 85℃,and the repair rate reaches 97.8%.In addition,the SMEP/PZS coating shows good corrosion resistance,and after the repaired coating is immersed in 3.5wt%NaCl solution for 14 days,its corrosion resistance is closed to the original coating.When the SMEP/PZS coating is coated on the stainless steel substrate,the pitting corrosion potential Eb measured in 3.5wt%NaCl solution has increased by nearly 10 times compared with that of the bare stainless steel,and the passive current density Ip has decreased by 2 orders of magnitude,showing relatively longer corrosion resistance and protection for 304 stainless steel substrate.Finally,the self-healing and anti-corrosion mechanism of SMEP/PZS coating is further discussed.