Chemical and Biomolecular Engineering Faculty Research


Alternative Method for Determining Surface Energy by Utilizing Polymer Thin Film Dewetting

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Publication Date

Spring 2003


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.





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