Adsorption of polymer/solvent complexes on silica surfaces

In this work local chain conformation, polymer/solvent interactions and par ticle size of different PMMA/solvent or PMMA/surfactant/solvent systems wer e investigated by dynamic light scattering, infrared spectroscopy and capil lary viscosimetry. Aggregation can be forced, in the chlorinated solvents, through mixing with a small amount of PEG non-ionic surfactants. Nano-gel p articles can also be formed by stereocomplexation of i- and s-PMMA in certa in solvents. The adsorption of stereoregular PMMA on silica was investigate d by H-1 NMR. The strong relative lowering of the peak ascribed to isotacti c sequences has provided evidence of a stereospecific adsorption of the iso tactic segments. The conformation and the secondary structure induced by th e PMMA stereoregularity may, therefore, be considered as a significant fact or in the adsorption process. According to the miscibility of the component s, PMMA/PEG mixtures are shown to increase the amount of polymer adsorbed a nd also to modify the stereoselectivity of the adsorption. Aggregative adso rption is assumed to deeply influence the organisation of the polymer at th e silica/solvent interface. Finally, adsorption of aggregates of stereocomp lexes can be used to pattern surfaces in thin Films.