Abstract
Low-temperature NH3/He-microplasma under a high-pressure environment close to atmospheric pressure (720-730 Torr) has been employed for local surface modification of nitrogen groups on the surface of plasma-polymerized styrene (pp-styrene). As a result of optical emission spectroscopy (OES) measurement, the gas temperature of low-temperature NH3/He-microplasma was Tg ≈ 290 K and proved the treatment to be less thermal damage for the polymer. Also, from the measurement of Lissajou figure, the estimated electron temperature and the mean electron density was Te≈ 105 K and Ne ≈ 107 cm-3, respectively. X-ray photoelectron spectroscopy (XPS) measurement results show that the nitrogen and oxygen groups were modified locally on the surface of pp-styrene film by the treatment of NH3/He-low-temperature plasma. The diameter of modified nitrogen groups' area corresponds to that of the glass capillary (500μm) at the end of microplasma torch. Furthermore, the resonant frequency decline of the treated pp-styrene-coated surface transverse wave (STW) acoustic device suggested that NH3/He-low-temperature plasma raised the water adsorption on the surface of pp-styrene film. In maximum, the water adsorption increased 2.63 times compared to untreated one.
