摘要
为了提高TiO2薄膜的光致亲水性及其持久性,将聚乙二醇(PEG)2000引入TiO2溶胶中,利用提拉法在载玻片上制备出含PEG的TiO2薄膜样品,通过测试样品紫外光照下水滴接触角的变化,考察不同浓度PEG对TiO2薄膜光致亲水性能的影响;并通过测试光照后的亲水薄膜样片暗处放置不同时间后接触角的变化,比较含PEG的TiO2薄膜和纯TiO2薄膜样品的亲水持久性.结果表明:PEG作为一种非离子型长链分子,其适量的添加可促进TiO2薄膜的光致亲水性及其持久性.基于薄膜样品的傅里叶变换红外(FTIR)光谱和紫外-可见漫反射光谱(UV-VisDRS)结果,认为PEG作为空穴捕获剂有助于TiO2薄膜中Ti3+的生成和稳定存在,进而有助于亲水中心(表面羟基)的形成.此研究对于TiO2光自洁涂料的应用很有意义,也为研究TiO2的光激发瞬态行为提供了一个可能的简易方法.
To investigate the photo-induced hydrophilicity of TiO2 films and its durability, a series of TiO2 films containing polyethylene glycol （PEG） 2000 with different contents are prepared. The photo-induced hydrophilicity of the films is investigated by recording the water-droplet contact angle on the films＇ surface under UV irradiation, and the hydrophilicity durability is monitored under dark storage conditions. The photo-induced hydrophilicity of TiO2 films and its hydrophilicity durability are enhanced by introducing 2.0% （w） of PEG into the TiO2 sol. From Fourier transform infrared （FTIR） spectra and ultraviolet-visible diffuse reflection spectra （UV-Vis DRS）, we infer that PEG acts as an electron donor to scavenge the photo- generated holes in TiO2 and promotes the formation of Ti^（3＋） sites, which are induced by the Ti^（4＋） sites accepting the photo-generated electrons of TiO2. This promotes the formation of hydrophilic sites （the surface hydroxyl species）. Compared with the pure TiO2 film, the Ti^（3＋） sites in the TiO2/PEG films are more stable, which prolongs the hydrophilicity of TiO2 films under dark conditions. This study is significant for the application of TiO2 as a self-cleaning material, and is also a facile approach to investigate the transient behaviors of TiO2 under UV irradiation.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2012年第7期1764-1770,共7页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(21073037)
国家重点基础研究发展规划项目(973)(2010CB234604)资助~~
关键词
光致亲水性
亲水持久性
空穴捕获剂
TIO2薄膜
Ti3+物种
聚乙二醇
Photo-induced hydrophilicity
Durability of hydrophilicity
Hole scavenger
TiO2 film
Ti^（3＋） species
Polyethylene glycol
