Contact-angle hysteresis, correlation with

These surface modifications were performed in "pure" micro-wave (2.45 GHz, "single-mode") or in combined microwave/ radio frequency (2.45 GHz/13.56 MHz, "dual-frequency") plasma. Important systematic changes of the surface composition, wettability, and adhesion of thin metal films were observed for different substrate bias values, and for the different gases. The modified surface-chemical structure is correlated with contact angle hysteresis of water drops this helps to identify which surface characteristics are connected with the wettability heterogeneity and with adhesive bonding properties, and how they are influenced by plasma-surface interactions. 

Table 3 gives similar results for the reactions with CAC and TAA. This time CAC reacts directly with the enolic -OH. Also shown are the water contact angles. Clearly there is no correlation between contact angle and adhesion. Broadly speaking the contact angle hysteresis is constant... 

All the surfaces exhibit adhesion hysteresis (i.e., Wu>Wl) to various degrees. The hysteresis, in general, is lower on PS than on PMMA, which may reflect that the silicone polymers engage in polar interactions with the latter substrate. We take the adhesion of the silicone polymers on polymethylmethacrylate as an indicator of the interaction between the silicone polymers and the acrylic adhesive. The trends of these adhesive energies, like the contact angles, are not consistent with the trend of the release profiles of the elastomers shown in Fig. 2. We next investigated whether there is any correlation between the release profiles of the various silicone elastomers and their interfocial slip characteristics tased on the methodology described by Newby and Chaudhury . 

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