Adhesion in water between ionic polymer surfaces

To study the electrostatic interaction between two ionic polymer surface, a polyester film surface was graft-polymerized with a cationic monomer, N,N-dimethylaminoethyl methacrylate and an anionic monomer, acrylic acid. When the oppositely charged film pair was brought into contact in the presence of water, they showed strong adhesion instantaneously in water. The adhesion interaction was studied with both shear strength method and atomic force microscopy. The interaction depended on the graft density and the ionic nature of the graft chains. The addition of salt to the medium of the measurement caused a remarkable reduction in the adhesive interaction. These interactions were attributed to the coulombic force between the grafted ionic polymer chains. q1998 Elsevier Science B.V. All rights reserved