The self-adjusting polytetrafluoroethylene (PTFE)/TiO₂ organic-inorganic double-layer coatings are designed on titanium alloy using thermal field and gradient pressure field enhanced plasma electrolytic oxidation (TGEPEO), which leads to the in-situ incorporation of PTFE nano-particles into the bottom TiO₂ ceramic coating. The PTFE top layer with adjustable thickness is strongly bonded on a TiO₂ bottom porous layer by subsequent deposition, chemical bonding and crosslinking curing of PTFE nanoparticles during TGEPEO process. Simultaneously, the double-layer coating possesses promising self-cleaning function due to a special hydrophobic surface with a water contact angle of ≈138.0 ± 4.4° caused by self-adjusted surface micro-nano structure. Moreover, the PTFE/TiO₂ double-layer coating exhibits excellent corrosion resistance and high electrical insulation. More importantly, the microstructure of the double-layer coating underwent self-adjustment in long-term immersion, caused by the accumulation-redeposition of corrosive ions and the closure of the reticular microchannels at the damaged regions, thus enhancing long-term chemical stability.

自调节聚四氟乙烯（PTFE）/ TiO ₂有机-无机双层涂层是利用热场和梯度压力场增强等离子体电解氧化（TGEPEO）在钛合金上设计的，从而可原位掺入PTFE纳米级。颗粒进入底部TiO ₂陶瓷涂层。厚度可调的PTFE顶层牢固地粘合在TiO _2上通过在TGEPEO过程中对PTFE纳米颗粒进行随后的沉积，化学键合和交联固化，形成底部多孔层。同时，由于自调节的表面微纳结构引起的特殊疏水表面的水接触角约为138.0±4.4°，因此该双层涂层具有令人满意的自清洁功能。而且，PTFE / TiO ₂双层涂层显示出优异的耐腐蚀性和高电绝缘性。更重要的是，双层涂层的微观结构在长期浸没时会进行自我调节，这是由于腐蚀离子的积累-再沉积和受损区域的网状微通道的封闭所致，从而提高了长期化学稳定性。