Alternative method for determining surface energy by utilizing polymer thin film dewetting

Contact angle and contact mechanics, the most common estimating methods for surface energy, exhibit intrinsic drawbacks when determining surface energy or surface energy variation of micron-scaled areas. In this study, the dewetting of a polymer thin film was explored as a means for surface energy determination. In particular, two empirical plots were generated through modification of silicon wafers with various organosilanes and organosilane mixtures. One plot correlated dewetting velocity of a polystyrene thin film as a function of surface energy for both polar and nonpolar surfaces; the other plot consisted of variation of dewetting hole diameters with surface energy for strictly nonpolar surfaces. The empirical plots were then applied to deduce surface energies of micron-scaled areas of gradient and heterogeneous-patterned surfaces. This approach resulted in reasonable values with less than 1% difference as compared to those expected for perfluorodecyl- 1H, 1H,2H,2H-trichlorosilane/n-decyltrichlorosilane surfaces. But the difference was slightly higher (35%) for the n-octadecyltrichlorosilane (OTS) contact-printed surfaces, which might be a result of better contact with the surface and higher OTS concentration on the stamps when smaller stamps were used.