Adsorption of Poly(methyl methacrylate) on Silica Surfaces Having Various Silanol Densities

Abstract

Abstract The adsorption of poly(methyl methacrylate) (PMMA) on silica surfaces having various silanol densities was studied by ESR and IR spectroscopies. Three silica samples, Nipsil HD, Aerosil 300, and Aerosil R812, which have 8, 2.2, and 0.54 nm−2 silanol densities, respectively, were used as the adsorbents. The amount of adsorption, A, the surface coverage, θ, and the fraction of train segments in the polymer, p, were determined. The values of the segment fractions anchoring through the hydrogen bond in all train segments of the adsorbed polymer, fHB, were also estimated. When PMMA adsorbed on Nipsil HD, the polymer adsorbed predominantly by the formation of hydrogen bonds; on the other hand, when PMMA adsorbed on Aerosil 300, the polymer adsorbed through the hydrogen bond in the part of 30–40%. When PMMA adsorbed onto Nipsil HD, the value of pESR obtained by the ESR method was almost the same as the pIR obtained by the IR method. When PMMA adsorbed onto Aerosil 300, the value of pESR was 0.47, twice the value of pIR(0.24).