Analytical modeling of wetting dependence on surface nanotopography

An analytical model was developed to describe the mechanism of wetting dependence on surface nanotopography. This model relates the contact angle formation with the asperity geometry for application to a hydrophilic wafer surface, which is derived based on liquid–solid interfacial contact over the contact line. Experimental investigations were performed to verify the model. For much of the examined parameter room in the hydrophilic silicon wafer surface, it was found that the contact angle was strongly dependent on the ratio of asperity height to length, and the sharper asperity led to the higher contact angle. The observations are well consistent with Gibbs' contact-line theory.