@inproceedings{d0396b9a1c3c4a7b8c2a910af111f0d7,
title = "Reversible wetting of Titanium dioxide films",
abstract = "Titanium dioxide (TiO2) films were rendered hydrophilic through ultraviolet (UV) light irradiation (254nm) and returned to their previous hydrophobic condition when exposed to a sealed pressurized nitrogen atmosphere. UV light irradiation on TiO2 films resulted in super-hydrophilic surfaces with water contact angles of <5°. Alternatively, exposure of the films to an N2 environment resulted in relatively hydrophobic surfaces with water contact angles of >40°. The switching of TiO 2 surface wettability could be repeated on the same surface with little hysteresis in water contact angle values. The mechanism behind the hydrophilic and hydrophobic reversal in TiO2 surfaces is proposed to be due to UV light mediated photocatalysis and physio- adsorption of N 2 molecules respectively. The non-intrusive control of TiO 2 surface wettability could be an attractive alternative to other wettability-based microfluidic valving strategies like electrowetting and photochromic wetting variation. The above results are discussed in terms of the potential use of the films in wettability based valving and repeated wettability patterning of TiO2 surfaces for open and sealed microfluidic systems.",
keywords = "Hydrophilicity, Hydrophobicity, Microfluidics, N, Photocatalysis, Titanium dioxide",
author = "Toh, {A. G.G.} and Nolan, {M. G.} and R. Cai and Butler, {D. L.}",
year = "2008",
doi = "10.1117/12.759438",
language = "English",
isbn = "9780819469717",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "Society of Photo-Optical Instrumentation Engineers",
booktitle = "Device and Process Technologies for Microelectronics, MEMS, Photonics, and Nanotechnology IV",
address = "United States",
note = "Device and Process Technologies for Microelectronics, MEMS, Photonics, and Nanotechnology IV ; Conference date: 05-12-2007 Through 07-12-2007",
}