Fabrication of hydrophilic graphene film by molecular functionalization

• Published in: Physica Status Solidi. B: Basic Solid State Physics Vol. 254; no. 2; pp. np - n/a
• Main Authors: Taniguchi, Yoshiaki, Miki, Tsubasa, Mitsuno, Takanori, Ohno, Yasuhide, Nagase, Masao, Minagawa, Keiji, Yasuzawa, Mikito
• Format: Journal Article
• Language: English
• Published: 01.02.2017
• Subjects: biosensors; Contact angle; Electrical resistivity; epitaxy; Graphene; hydrophilicity; Langmuir-Blodgett films; Phosphorylcholine; Solid state physics; Surface chemistry; Time dependence
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201600524

We demonstrated the fabrication of a hydrophilic graphene film by functionalization using a phosphorylcholine group. Since the phosphorylcholine group retains water molecules, it is expected that a hydrophilic graphene film can be realized from the initial hydrophobic characteristic. To evaluate the molecular functionalization, the contact angle and four‐terminal resistivity were measured after every 1 min of phosphorylcholine group functionalization. The contact angle showed a sudden decrease of approximately 20° after 3 min. On the other hand, the resistivity gradually increased in accordance with the Langmuir adsorption isotherm. These results indicate that the phosphorylcholine group successfully modified the surface of graphene, and a hydrophilic graphene film was obtained without significant degradation of the electrical characteristics. Time dependence of the net contact angle change and resistivity change. The insets show the photographs of the contact angle measurement for the initial hydrophobic film and for the hydrophilic film obtained by functionalization.