Microphase Separation and Wetting Properties of Palmitate-graft-poly(vinyl alcohol) Films

Bulk and surface organization properties of grafted copolymers having an hydrophilic poly(vinyl alcohol) backbone and hydrophobic palmitic side chains were investigated. A structural study shows the existence of a microphase separation into lamellar structures for grafting ratios of only 0.09. Water wettability of films obtained by solvent casting from these grafted copolymers indicates a good segregation and organization of the alkyl chains at the surface of the films even at grafting ratio as low as 0.04. The quality of the solvent used during the copolymer film formation is shown to have a strong influence on organization and wetting properties of these materials. The existence of specific interactions of H-bond type in the PVA phase seems to be responsible for a strong incompatibility between the hydrophilic backbone and the hydrophobic side chains leading to such surprisingly good bulk and surface organizations.