Large-Scale Plasma Polymer Coating on Heat Exchanger Fins for Improving the Wettability

This research presents the results of the recently developed large-scale hydrophilic polymer coating by plasma polymerization, optimum plasma zone (OPZ) process. The excellent hydrophilicity of heat exchanger fin surface could give good effects to efficient drainage of condensate water as well as heat transfer performance. The hydrophilicity of layer treated by large-scale OPZ system is excellent irrespective of line speed from 0.6 m/min to 2.4 m/min. The good lateral uniformity of the hydrophilicity could be acquired in large scale OPZ treatment. The application of OPZ technique to the heat exchanger could enhance the efficiency of heat transfer, resulting from decrease of pressure drop. Due to long-term durability of hydrophilicity, the heat transfer performance improved by OPZ process cannot be deteriorated with operation cycle

Permanent Hydrophilic Surface Formation by Ion Assisted Reaction

Since totally wettable hydrophilic polymer surfaces from hydrophobic polymers (PMMA, PTFE, PET and PC) have been demonstrated for the first time at Materials Research Society meeting, 1995 Fall meeting, Boston, the application of ion assisted reaction (IAR), in which energetic ions (0.5~1.5 keV) are irradiated on materials with blowing reactive gases near the irradiating surfaces, has been extended to various polymer, ceramic and metal for creating permanent hydrophilic surfaces. The surface energy was measured by Youngs equation and the highest energy, Es, of 60~70 mN/m, which is similar to surface energy of water (Es of H2O : 72 mN/m) is obtained by controlling ion dose, energy, and amount of blown gas. The higher surface energy of materials possesses the more wettable surface, and relation between wettability and adhesion has been discussed. The remarkable result is the strong adhesion of inert nonattachable material such as Pt on the modified surface. The improvements of adhesions, wettability and surface energy are mainly due to polar force and hydrophilic functional groups such as C=O, (C=O)-O, C-O, etc. on the modified surface without surface damage by surface analyses. Advantages of the method are (1) high reproducibility, (2) simplicity, (3) changing ability of wettability degree, and (4) easy connection to conventional semiconductor process line. Improvements of efficiencies by changing heat transfer coefficients have been presented for the compact heat exchanger system