Polymer coatings of brushlike monolayers composed of two different polymers, polystyrene and poly(2-vinylpyridine), are grafted by radical polymerization on the surface of silicon wafers. Thickness, grafting
density, molecular weight of grafted chains, and the composition of the coatings were regulated by grafting
time, monomer concentration, and additional initiator in solution. A typical dry film thickness is between
10 and 100 nm, and the molecular weights of the components range from 100 to 300 kg/mol. The fabricated
coatings turn out to be sensitive to the composition of the environment. For instance after exposition to
toluene the layer becomes hydrophobic and the top of the layer is covered by polystyrene. After exposition
to HCl the layer becomes hydrophilic with polyvinylpyridine in the upper layer. This reconstruction of the
polymer layer was observed with contact angle and X-ray photoelectron spectroscopy measurements. The
composition of the top layer in different media is controlled by the composition and molecular weight of
the two polymers in the coating. The “switching” properties of the coating are shown to be reversible.
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