Abstract

The published communications devoted to studying the phenomenon of photoinduced hydrophilicity of the surfaces of thin metal oxide films have been reviewed. This phenomenon underlies the capability of photoactive materials for self-cleaning. The novelty of the work consists in the generalization and the critical analysis of the vast information obtained on the problem under consideration beginning from the discovery of the photoinduced superhydrophilicity of titanium dioxide in 1997 up to the present. The essence of the phenomenon and the mechanisms proposed for it have been described, and the examples of the influence of different factors on the kinetics and thermodynamics of this photoinduced process have been presented. A mechanism of the process has been suggested. It is based on the photoactivation and photodeactivation of surface active sites responsible for subsequent restructuring of adsorbed water molecules in a hydroxyl-hydrated multilayer on an oxide film surface, with the restructuring leading to a change in the surface free energy and, hence, the surface hydrophilicity. In conclusion, possible methods have been considered for controlling the wettability of the surfaces of photoactive materials with the use of light, with the method of creating heterostructured coatings being especially singled out among them.

中文翻译：

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薄膜表面的光致亲水性

摘要

审查了已发表的致力于研究金属氧化物薄膜表面光诱导亲水性现象的通讯。这种现象是光敏材料自清洁能力的基础。这项工作的新颖之处在于，对从1997年发现光诱导的超亲水性二氧化钛到目前为止所考虑的有关该问题的大量信息进行了概括和严格的分析。描述了该现象的实质及其提出的机理，并举例说明了不同因素对该光致过程的动力学和热力学的影响。已经提出了该过程的机制。它基于表面活性位的光活化和光失活，这些光活化和光失活负责随后重新构筑氧化膜表面上羟基水合多层膜中的吸附水分子，该重构导致表面自由能以及表面的变化亲水性。总之，已经考虑了使用光来控制光敏材料表面的润湿性的可能方法，其中特别是产生异质结构涂层的方法。