Reversible pH-Responsive Surface: From Superhydrophobicity to Superhydrophilicity


  • Financial support from the Major State Basic Research Development Program (Grant. No. G2000078102), 863 High-tech R&D Program (2003AA302140), the National Natural Science Foundation of China (20334010, 20473045), and the Ministry of Education is gratefully acknowledged.


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A pH-responsive surface has been fabricated by chemisorption of HS(CH2)9CH3 and HS(CH2)10COOH in an appropriate ratio onto a fractal-like gold structure. The surface exhibits superhydrophobicity in an acidic environment and superhydrophilicity under basic conditions. The Figure (right, top) shows an acid droplet on the gold surface, while the image below it shows a base droplet.