Effect of addition of second metal oxide on hydrophilic property of TIO[subscript 2] thin film

Abstract

Titanium dioxide (TiO[subscript 2]) and other metal oxides, i.e., ZnO, ZrO[subscript 2], and Fe[subscript 2]O[subscript 3], were synthesized using sol-gel methods. Then TiO[subscript 2] sol was mixed with the sol of another metal oxide so as to obtain the content of the second metal oxide in the range of 0 to 10 mol%. The mixed oxide sols were coated on glass slides using ultrasonic spray coater. The coated slides were calcined at 350 degrees Celsius for two hours. The hydrophilic property of thin films was measured using contact angle measurement. The addition of ZnO or ZrO[subscript 2] to TiO[subscript 2] in an appropriate amount could enhance the hydrophilic property of the mixed oxide thin films, as seen in the faster rate of decrease of contact angle towards a saturated value upon exposure to ultraviolet irradiation. The enhancement of the hydrophilic property of the film could be attributed to increases in the amounts of Ti[superscript 3+] and acid site present on the surface of TiO[subscript 2]. Furthermore, addition of ZnO or ZrO[subscript 2] to TiO[subscript 2] also improved the ability of thin films to retain hydrophilicity after removal of ultraviolet irradiation. Fe[subscript 2]O[subscript 3] was also added to TiO[subscript 2] thin film but did not improve hydrophilicity of the thin films.