Effect of Titania Colloid Solution Concentration on Hydrophobicity of Well-Aligned TiO2 Nanorods Synthesized via Hydrothermal Method

Among one dimensional nanomaterials, TiO2 nanorods have found important applications in various industries due to optical, photocatalyst and self-cleaning properties. In this research, at first TiO2 nanorods were synthesized on a glass substrate by hydrothermal method. Then a thin film of TiO2 particles was dip coated (as seed layer) on the substrate. After that, hydrothermal synthesis of TiO2 nanorods with 0.05 and 0.1 mol concentrations was carried out on the seed layer. Morphology and microstructure of the seed layer and nanorods were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). Hydrophobicity of nanorods was studied by contact angle instrument. Results revealed that nanorods synthesized on the glass substrate without seed layer are not aligned at all and have the average diameter of 120 nm, whereas nanorods synthesized on the seed layer are well-aligned with 30nm average diameter. The result obtained from contact angle instrument showed that nanorods synthesized with 0.05mol concentration have larger contact angle (157º), compared to those synthesized with 0.1mol concentration which have 115º contact angle.