氧化石墨烯-形状记忆环氧树脂/全氟癸基三甲氧基硅烷-聚二甲基硅氧烷@SiO2超疏水涂层的光热自修复与耐蚀性

Photothermal self-healing and corrosion resistance of graphene oxide-shape memory epoxy resin/perfluorodecyltrimethoxysilane-polydimethylsiloxane@SiO2 superhydrophobic coatings

  • 摘要: 针对物理损伤修复时间较长、修复率较低及极端条件下不锈钢易被腐蚀等实际问题,本文以具有光热效应的自修复涂层氧化石墨烯-形状记忆环氧树脂(GO-SMEP)为底层,以多级粗糙微纳米结构的超疏水涂层全氟癸基三甲氧基硅烷-聚二甲基硅氧烷@二氧化硅(PFDT-PDMS@SiO2)为表层,基于双层设计获得了一种快速修复物理损伤的光热自修复超疏水涂层GO-SMEP/PFDT-PDMS@SiO2 (GO-SMEP/PPS),并对该涂层的制备优化及其润湿性、光热效应、耐蚀性、自修复等性能进行研究。结果表明,当PDMS∶μ-SiO2∶n-SiO2质量比=1.5∶1∶1,PFDT含量为30wt%时,GO-SMEP/PPS涂层在304不锈钢基底上的超疏水性最佳,并表现出明显的镜面现象及对液滴高度排斥。GO-SMEP/PPS涂层的光热效应随着光热转化剂GO含量的增加而增强,GO含量为0.5wt%的GO-SMEP/PPS涂层经3周期的近红外光循环辐射,其光热效应保持稳定。将GO-SMEP/PPS受损涂层置于808 nm近红外光下,经3 min短时间的辐射,其物理划痕由40 μm修复至1 μm左右,基于修复前后涂层的低频阻抗模量(|Z|0.01 Hz)进一步计算其修复率高达97.5%。交流阻抗谱(EIS)分析表明,GO-SMEP/PPS(0.5wt% GO)涂层的耐蚀性由GO-SMEP底层和PPS表层共同决定,其容抗弧半径大,低频阻抗模量|Z|0.01 Hz高达3.2×105 Ω·cm2,对腐蚀性介质的阻隔性强,表现出良好的耐蚀性。在304不锈钢基底上涂覆该涂层后,所测点蚀电位(Eb=0.263 V)和维钝电流密度(Ip=4.80×10−8 A/cm2)表明对不锈钢防腐效果良好。

     

    Abstract:
    In this paper, based on the two-layer design, a photothermal self-healing superhydrophobic
    coating graphene oxide-shape memory epoxy resin (GO-SMEP)/perfluorodecyltrimethoxysilane-polydimethylsiloxane (PFDT-PDMS)@SiO2 (GO-SMEP/PPS) that could quickly repair physical damages was prepared. Aiming to solve the practical problems of the physical damage repair time is long, the repair rate is low, and stainless steel is susceptible to corrosion under extreme conditions for a long time. The double-layer coating was designed by combination of self-healing coating with photothermal effect GO-SMEP and the superhydrophobic coating with multi-level rough micro-nano structure PPS. Furthermore, the preparation optimization of the coating and its wettability, photothermal effect, corrosion resistance, self-healing and other properties were studied.The results show that when mass ratio of PDMS∶μ-SiO2∶n-SiO2=1.5∶1∶1 and the PFDT content is 30wt%, the superhydrophobicity of the GO-SMEP/PPS coating on the 304 stainless steel substrate is the best, and exhibits apparent specularity and high repulsion to droplets. The photothermal effect of the GO-SMEP/PPS coating is enhanced with the increase of the photothermal conversion agent GO content, and the GO-SMEP/PPS coating with a GO content of 0.5wt% is subjected to 3 cycles of near-infrared light cycling radiation, its photothermal effect remains highly stable.The damaged GO-SMEP/PPS coating was placed under 808 nm near-infrared light, and the physical scratches were repaired from 40 μm to about 1 μm after a short period of irradiation for 3 min. Based on the low-frequency impedance modulus of the coating before and after repair (|Z|0.01 Hz) further calculates the restoration rate as high as 97.5%. The AC impedance spectroscopy (EIS) analysis shows that the corrosion resistance of the GO-SMEP/PPS (0.5wt% GO) coating is jointly determined by the GO-SMEP bottom layer and the PPS surface layer, with the largest capacitive arc radius and the low-frequency impedance modulus |Z|0.01 Hz is as high as 3.2×105 Ω·cm2, which has the strongest barrier to corrosive media and shows good corrosion resistance. After applying the coating on 304 stainless steel substrate, the measured pitting corrosion potential (Eb=0.263 V) and passive current density (Ip=4.80×10−8 A/cm2) shows good corrosion resistance to stainless steel.

     

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