Condensation on hydrosol modified polyethylene

Water vapour condensation was examined on polyethylene film and polyethylene film that was modified to promote improved wetting properties. The objective was to produce filmwise rather than dropwise condensation of water vapour, given the filmwise condensate has improved optical properties for the transmission of light, and leads to more coherent images. On the untreated polyethylene film the drop geometry was nearly spherical. However, when the surface was modified using a Corona Discharge treatment the drop geometry was distorted significantly, however, remained discrete. The wetting properties were further improved when the untreated polyethylene film was modified by depositing tin hydrosol particles onto the surface. However, over time there was a significant degradation in the quality of the two surface treatments, resulting in a similar level of performance. When the Corona Discharge treated polyethylene film was treated with the tin hydrosol; however, the condensation proceeded by a filmwise mechanism almost immediately. Over time the effectiveness of the combined treatment did not degrade in any way. Clearly, the adhesion of the tin–hydrosol particles to the Corona Discharge treated polyethylene film was much stronger, and in turn the water condensation proceeded by a filmwise mechanism.