The wettability of graphene has been extensively studied and successfully modified by chemical functionalization. Nevertheless, the unavoidable introduction of undesired defects and the absence of systematic and local control over wettability by previous methods have limited the use of graphene in applications. In addition, microscale patterning, according to wettability, has not been attempted. Here, we demonstrate that the wettability of graphene can be systematically controlled and surface patterned into microscale sections based on wettability without creating significant defects, possible by nondestructive hydrogen plasma. Hydrophobic graphene is progressively converted to hydrophilic hydrogenated graphene (H-Gr) that reaches superhydrophilicity. The great contrast in wettability between graphene and H-Gr makes it possible to selectively position and isolate human breast cancer cells on arrays of micropatterns since strong hydrophilicity facilitates the adsorption of the cells. We believe that our method will provide an essential technique for enabling surface and biological applications requiring microscale patterns with different wettability.
Bibliographical noteFunding Information:
This research was supported by programs through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2018R1D1A1B07048187, NRF-2019R1A2C2002960 (J.H.) and NRF-2017R1A5A1014862 (G.H.L.)).
Copyright © 2020 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering