Preparation of gradient wettability surface by anodization depositing copper hydroxide on copper surface
(School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China)
Abstract: A facile route for preparation of gradient wettability surface on copper substrate with contact angle changing from 90.3° to 4.2° was developed. The Cu(OH)2 nanoribbon arrays were electrochemically deposited on copper foil via a modified anodization technology, and the growth degree and density of the Cu(OH)2 arrays may be controlled varying with position along the substrate by slowly adding aqueous solution of KOH into the two-electrode cell of an anodization system to form the gradient surface. The prepared surface was water resistant and thermal stable, which could keep its gradient wetting property after being immersed in water bath at 100 °C for 10 h. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) demonstrate that the distribution of Cu(OH)2 nanoribbon arrays on copper surface are responsible for the gradient wettability.
Key words: gradient wettability surface; Cu(OH)2 nanoribbon array; anodization depositing; contact angle