Graphene coatings may help change material properties

New research conducted at MIT shows that while graphene preserves the properties of materials with intermediate wettability, in more extreme cases – such as with superhydrophobic or superhydrophilic surfaces – an added layer of graphene changes the way coated materials behave significantly. According to the researchers, that's an important finding. Until recently, coating a superhydrophobic material with graphene was seen as a possible way of making electronic circuits that would be protected from shortcircuiting and corrosion in water. But it's not quite that simple, they point out. Professor Daniel Blankschtein said: "This finding may be viewed as a negative result, but it is nevertheless extremely important because it [shows] what can actually be accomplished in practice." The research, which included both theoretical modeling and experimental confirmation, showed that by depositing a large graphene sheet on another material's surface using chemical vapour deposition it is possible to induce electrical conductivity on that surface while partially preserving the desired surface wetting behaviour. The team describes this partial transmission of the underlying characteristics as 'translucency', rather than transparency. By selecting a particular combination of an underlying material with a graphene coating, different combinations of electrical, optical and wetting characteristics can be achieved. Researcher Chih-Jeh Shih said: "This breakthrough successfully decouples the conductivity and wettability of a material." The work is believed to open up new possibilities for practical devices, because the materials involved are already widely used in industry. Shih concluded: "Due to its compatibility with today's semiconductor processes, many exciting opportunities may be pursued in the areas of microelectronics, nanoscale heat transfer and microfluidic devices — to simultaneously engineer desired wettability, heat transfer and electronic transport."