Abstract A series of hybrid sol-gel matrices were synthesized using 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) incorporating caffeine extracted from leaves of tea. Corrosion inhibition performances of coated mild steel panels exposed to 3.5 wt.% NaCl were evaluated employing electrochemical measurements. Data acquired using complementary corrosion analyses were in accordance where 100 ppm caffeine-doped hybrid sol-gel coating offered the highest inhibition efficiency at 88.79 %. Tafel curves suggested that silane coatings mitigated both the anodic and cathodic reactions simultaneously, i.e. a mixed-type inhibition. Coatings were characterized using FT-IR, SEM/EDX and water contact angle measurements. IR absorption peak obtained at 954 cm−1 revealed the formation of Fe O Si bonds. 100 ppm caffeine-doped silane coating offered the highest corrosion resistance since the corrosion protective barrier minimized the oxidation of mild steel to a greater extent where the EDX analysis showed a high intense signal of Fe. Water contact angle analysis depicted the hydrophobicity of coated panels suggesting the tendency of being less prone to water.

中文翻译：

---

掺杂咖啡因的混合溶胶-凝胶 (TEOS-APTES) 作为 3.5 wt.% NaCl 中低碳钢的强腐蚀保护涂层的敏感性

摘要 使用 3-氨基丙基三乙氧基硅烷 (APTES) 和原硅酸四乙酯 (TEOS) 结合从茶叶中提取的咖啡因合成了一系列混合溶胶-凝胶基质。使用电化学测量评估暴露于 3.5 wt.% NaCl 的涂层低碳钢板的腐蚀抑制性能。使用补充腐蚀分析获得的数据与 100 ppm 掺杂咖啡因的混合溶胶-凝胶涂层的抑制效率最高，为 88.79%。Tafel 曲线表明硅烷涂层同时减轻了阳极和阴极反应，即混合型抑制。使用 FT-IR、SEM/EDX 和水接触角测量来表征涂层。在 954 cm-1 处获得的 IR 吸收峰揭示了 Fe O Si 键的形成。100 ppm 咖啡因掺杂的硅烷涂层提供了最高的耐腐蚀性，因为腐蚀保护屏障在更大程度上最大限度地减少了低碳钢的氧化，其中 EDX 分析显示了高强度的 Fe 信号。水接触角分析描述了涂层板的疏水性，表明其不易受水影响。