Superhydrophilicity of Highly Textured Carbon Films in Range of pH Values from 0 through 14

In the past few years, the study of superhydrophilic surfaces has attracted considerable attention, clue to their great potential in not only fundamental research but also practical applications. However, the bottlenecks in this field are (1) the use of UV irradiation, (2) the chemical modification by high-free-energy materials. and (3) the unavailability of useful superhydrophilic surfaces throughout the range of pH values from 0 through 14. In this article, we describe a method for inducing rough features on carbon surfaces using plasma technique to acquire superhydrophilic character. More interestingly and importantly, the as-prepared films are superhydrophilic for not only pure water but also corrosive liquids, such as acidic and basic solutions. This is the first example of superhydrophilicity over the whole range of pH values without the presence of high-free-energy compounds and in the absence of UV irradiation and might open up new perspectives in preparing novel nanoscale interfacial materials. The method of surface design described here does not require the use of masks or lithography, can be applied to very large surfaces in very short time, and herein offers an inexpensive and rapid method for improving the wettability of materials.