NOTE Adhesive Interaction in Water between Surfaces with Various Zeta Potentials
EXPERIMENTAL
To obtain polymer surfaces having different zeta potentials, a poly(ethylene terephthalate) (PET) film surface was graft-poly-Materials merized with an anionic monomer, acrylic acid (AAc), and a
The PET and cellulose films used were of commercial grade and both cationic monomer, N,N-dimethylaminoethyl methacrylate (DMAhad a thickness around 40 mm. Purification of these films was performed EMA). In addition, a cellulose film was surface-modified with by Soxhlet extraction with methanol for 20 h before use. AAc, DMA- chloroacetic acid to introduce anionic carboxyl groups and N,N-EMA, and DMAPAA were all of chemical grade and purified by conven- dimethylaminopropyl acrylamide (DMAPAA) to introduce cattional distillation. Chloroacetic acid was used as received. Quartz glass ionic dimethylamino groups. Through these surface modifications was used after immersion in a hot chromic acid mixture for 24 h followed by rigorous washing with distilled water.
we could obtain films having zeta potentials ranging from /39 to 058 mV. Adhesive interaction in water between two surfaces of Surface Modification of Films these films was measured with a tensile testing method after lapping the two surfaces in water. When one film was surface-grafted Surface graft polymerization of AAc and DMAEMA onto the PET film with cationic polymer chains, it exhibited significant adhesion inwas carried out with the procedure described elsewhere (3). Briefly, a strip stantaneously in water toward the other surface with a negative of film of 1.5 1 6 cm 2 was placed in a Pyrex test tube, together with 10 zeta potential, such as the surface-modified cellulose films, quartz, wt% aqueous monomer solution, to which sodium periodate was added by 5 1 10 04 M. To effect graft polymerization, the mixture was kept at 30ะC and the unmodified PET film. The quartz surface showed a detectwithout degassing and irradiated with UV from a high-pressure mercury able attractive force toward the cationic cellulose surface, but the lamp for 1.5 h. The homopolymer contaminating the grafted surfaces was force was weaker than that toward the cationically grafted surface.
removed by water extraction for 24 h. The graft density was determined with Apparently, no correlation was found between the zeta potential a C.I. Acid Orange 7 dyeing method for the film grafted with DMAEMA of the surfaces and their adhesive strength.