A Hybrid Method Employing Breakdown Anodization and Electrophoretic Deposition for Superhydrophilic Surfaces

A fabrication method is developed for superhydrophilic surfaces with high capillary pressure and fast spreading speed. The fabrication method consists of electrophoretic deposition (EPD) and breakdown anodization (BDA). Nanopores and micropores were produced on titanium plates by EPD and BDA, respectively. In EPD, TiO2 nanoparticles were used to enhance the surface energy and create nanoporous structures, while BDA was employed to produce microporous structures. Capillary rise measurements (CRM) were utilized to characterize superhydrophilic surfaces in terms of capillary pressure and spreading speed. From CRM, it was revealed that microporous structures play a dominant role in determining transport properties, and nanoporous structures affect local wettability without significantly reducing spreading speed. By combining BDA and EPD into a hybrid method, dual-scale (nano and micro) porous structures were produced on titanium plates. The methods presented offer the potential to vary the transport characteristics of superhydrophilic surfaces by altering the nanoscale and microscale features independently. As an example, surfaces with unconventional capillary flows were produced by the hybrid method. This method provides additional opportunities to investigate wetting phenomena while offering a potentially low cost process for industrial applications.