In this study, functional-group-retaining polymerization of hydroxyethyl methacrylate (HEMA) was carried out by using an atmospheric pressure non-equilibrium Ar plasma jet. The polymeric films deposited under different conditions were characterized by Fourier transform infrared spectroscopy (FT-IR). The FT-IR spectra show that HEMA was polymerized (carbon-carbon double bond disappeared) and the main functional groups were successfully retained in the plasma-polymerization films. The plasma-polymerization mechanism and the polymerization reaction kinetics will be discussed.

A non-equilibrium atmospheric pressure plasma was applied for the polymerization of the methacrylic monomers such as (2-hydroxyethyl methacrylate (HEMA), methacrylic acid (MAA) and butyl methacrylate (BMA)). These monomers were successfully polymerized with retaining the functional groups of ester or acid. The polymerization mechanism was discussed on the basis of the optical emission spectroscopy (OES) of the plasma. It was strongly suggested that the functional groups could be retained in the polymerization proceeds when the HOMO-LUMO gap of the monomer is close to the energy of Ar metastable atom, which initiates the polymerization.

In this study, a 35-μm-thick copper sub-micron paste (particle diameter of 700 - 900 nm) was printed on an alumina substrate, and then sintered by conventional heating treatment and by atmospheric pressure plasma (APP) treatment, respectively. Surface micro-structures of the printed films sintered by both methods were observed by SEM. As a result, copper sub-micron particles were successfully sintered at a relatively low temperature by APP treatment. Through the SEM micrographs we suppose that the sintering processes by both methods are quite different.