Duan Zhuoqi, Xie Zaixin, Hu Yongmao, Xu Jiawen, Ren Jun, Liu Yu, Nie Heng-Yong
College of Engineering, Dali University, Dali 671003, China.
Surface Science Western, The University of Western Ontario, London, ON N6G 0J3, Canada.
Molecules. 2024 Feb 3;29(3):706. doi: 10.3390/molecules29030706.
Aluminum (Al) placed in hot water (HW) at 90 °C is roughened due to its reaction with water, forming Al hydroxide and Al oxide, as well as releasing hydrogen gas. The roughened surface is thus hydrophilic and possesses a hugely increased surface area, which can be useful in applications requiring hydrophilicity and increased surface area, such as atmospheric moisture harvesting. On the other hand, when using HW to roughen specified areas of an Al substrate, ways to protect the other areas from HW attacks are necessary. We demonstrated that self-assembled monolayers (SAMs) of a fluorinated phosphonic acid (FPA, CF(CF)(CH)P(=O)(OH)) derivatized on the native oxide of an Al film protected the underneath metal substrate from HW attack. The intact wettability and surface morphology of FPA-derivatized Al subjected to HW treatment were examined using contact angle measurement, and scanning electron microscopy and atomic force microscopy, respectively. Moreover, the surface and interface chemistry of FPA-derivatized Al before and after HW treatment were investigated by time-of-flight secondary ion mass spectrometry (ToF-SIMS), verifying that the FPA SAMs were intact upon HW treatment. The ToF-SIMS results therefore explained, on the molecular level, why HW treatment did not affect the underneath Al at all. FPA derivatization is thus expected to be developed as a patterning method for the formation of hydrophilic and hydrophobic areas on Al when combined with HW treatment.
置于90℃热水（HW）中的铝（Al）会因其与水的反应而变得粗糙，形成氢氧化铝和氧化铝，并释放出氢气。如此一来，粗糙的表面具有亲水性，且表面积大幅增加，这在诸如大气水分收集等需要亲水性和增加表面积的应用中可能会很有用。另一方面，当使用热水对铝基板的特定区域进行粗糙化处理时，有必要采取措施保护其他区域免受热水侵蚀。我们证明，在铝膜的天然氧化物上衍生化的氟化膦酸（FPA，CF(CF)(CH)P(=O)(OH)）自组装单分子层（SAMs）可保护下方的金属基板免受热水侵蚀。分别使用接触角测量、扫描电子显微镜和原子力显微镜对经过热水处理的FPA衍生化铝的完整润湿性和表面形态进行了检测。此外，通过飞行时间二次离子质谱（ToF-SIMS）研究了FPA衍生化铝在热水处理前后的表面和界面化学，证实了FPA自组装单分子层在热水处理后保持完整。因此，ToF-SIMS结果在分子层面解释了为什么热水处理根本不会影响下方的铝。因此，当与热水处理相结合时，FPA衍生化有望发展成为一种在铝上形成亲水和疏水区域的图案化方法。
