Surface modification of poly(ethylene-co-acrylic acid) with amino-functionalized silica nanoparticles

In this work we studied the possibility to achieve a hybrid-surface through the modification, via a facile wet chemical process, of the surface of films of poly(ethylene-co-acrylic acid) (EAA) with amino-modified silica nanoparticles. Films of EAA were preliminarily activated by the introduction of -COCl groups on their surface. Silica nanoparticles were thereafter covalently bound on the polymeric surface as confirmed by FTIR, ATR-FTIR, XPS, NMR and SEM determinations. The nanoparticles formed a multilayer on the film surface and covered almost uniformly the whole film surface. Direct measurements of superficial amino groups by titration allowed us to detect a concentration of about 18 nmol cm(-2). The presence of this uniform layer of nanoparticles bearing polar groups strongly changed the wettability of the material as confirmed by static contact angle measurements that passed from 87 degrees of the neat EAA to about 30 degrees of the amino-functionalized silica nanoparticles modified material.