Effect of Water Traces upon Adsorption of PMMA on Flat Substrates of Glass and Silica

Using IR spectroscopy and AFM, we investigated the effect of traces of water on the adsorbed amount and the morphology of the adsorbed layer in the adsorption of PMMA on flat silica and flat glass. To obtain very anhydrous solutions, we used a technique that involves the addition of molecular sieves to the solution. We showed that this method allows direct comparison of PMMA adsorption between dispersed and flat substrates of silica; in the absence of water in the solution, as is obtained with this technique, the amount of polymer adsorbed on flat silica is similar to amounts reported in the literature for dispersed silicas. We also showed that the adsorption of PMMA occurs in a similar way, with the same adsorbed amount and same layer morphology, onto glass and silica only when the adsorption takes place in an extremely anhydrous solution. On the contrary, when water molecules are present, the adsorbed amount of polymer increases on both substrates, with a higher amplitude on the glass substrates, and th...