Correlation between Hydrophilicity and Surface Aggregation in Anodized TiO2 Nanotube Arrays

Abstract

Abstract Aligned TiO 2 nanotube array through anodization method often comes with a surface aggregation layer of TiO 2 nanowires. To achieve high photoelectrochemical(PEC) performance, aggregation must be avoided during synthesis or removed via post-processing methods. We present here an efficient method of evaluating the extent of surface aggregation on TiO 2 nanotube arrays through water contact angle measurement. Our results indicate that water contact angle on a clean TiO 2 nanotube array is almost negligible, with a good correlation between aggregate coverage ratio and contact angles as the aggregation layer increases. This enables a convenient and reliable procedure for quantitatively characterize the surface aggregate level on a macroscopic scale.