Wettability gradient surfaces prepared by corona discharge treatment

In this study, we developed a new method to prepare wettability gradients on polymer surfaces by treating the polymer sheets with corona, in which the power output is gradually increased. The corona discharge treatment is more simple and practical method to prepare wettability gradient surfaces than the plasma discharge treatment because the samples are treated in air atmosphere. The prepared gradient surfaces can be used to systematically investigate protein, blood, or cell interactions in terms of the surface hydrophilicity/hydrophobicity of polymeric materials. The corona-treated PE surface did not show any noticeable change to the eye, but the wettability of the surface based on the measurement of water contact angle gradually increased along the sample distance with increasing power output (the contact angles gradually decreased from 90 to about 40 degree by the corona discharge treatment).