|AVS 57th International Symposium & Exhibition|
|Graphene Focus Topic||Tuesday Sessions|
|Session:||Graphene Focus Topic Poster Session|
|Presenter:||N. Tsuda, Nagoya University, Japan|
|Authors:||N. Tsuda, Nagoya University, Japan
Y. Aoki, Nagoya University, Japan
J. Hieda, Nagoya University, Japan
O. Takai, Nagoya University, Japan
N. Saito, Nagoya University, Japan
|Correspondent:||Click to Email|
Plasma in gas phase is widely used in many industrial fields such as electronic device manufacturing processes (plasma etching, sputtering, plasma-enhanced CVD, etc.), hard coating processes (ion plating, sputtering, etc.), surface treatment processes (low or atmospheric pressure plasma treatments, sputtering, plasma etching, etc.) and so on. Plasma in solid phase has been utilized finally for surface plasmon resonance (SPR) spectroscopy, nanoparticles, etc., and plasmonics is developing as a new research field. On the other hand, plasma in liquid phase is not generally well-known, although it has been partially utilized in water treatments and electrical discharge machining. The fundamentals of plasma in liquid phase have not been established, including its generation techniques, its state, and activated chemical species. However, it would be reasonable to expect a higher reaction rate under lower-temperature conditions, and the greater chemical reaction variability since the molecular density of liquid is much higher than that of gas phase. So we have named the plasma in liquid phase “solution plasma” because we make variety of plasma by choosing the combinations of solvents and solutes in solutions, and are developing solution plasma processing (SPP). In SPP, aqueous solutions, nonaqueous ones, liquid nitrogen, supercritical fluids, etc. can be utilized as solutions. Recently, we have investigated the features of SPP and the applications such as syntheses of nanoparticles and mesoporous silica, and surface modification of particles.
In this research, graphene sheet were modified by a glow discharge in solution. A pulsed power supply was used to generate discharges. The pulsed width was 2 micro seconds, the repetition frequency was 15 kHz. The electrode was tungsten wire in the diameter of 1 mm with electrode gap of 0.3 mm. ammonium aqueous solution was used as the medium around plasma. Graphene sheets were separated by oxidation. The grapheme sheets were added to the ammonium solution and irradiated by glow discharge in the solution. The solution and the productants after the discharge were analyzed by optical emission spectroscopy, IR spectroscopy, Uv-Vis spectroscopy, AFM, XRD and TEM. After the discharge, the graphene sheets were modified by amino functional groups. Moreover, the aminocaproic acid was grafted into the amino functional groups on graphene sheets. Finally, graphene sheets were solidified because the space of sheets was measured.