(227d) Adhesion of Polymer/Laponite Nanocomposite Hydrogels As Determined By Jkr Instrument
Biocompatible nanocomposite hydrogels (NC gels) consisting of poly(acrylic acid) (PAA), poly(methacrylic acid), or poly(acrylic acid-co-N-isopropylacrylamide) and nano-sized clay (Laponite) were successfully synthesized by in-situ free radical polymerization of monomers in aqueous solutions of Laponite. The obtained NC gels were uniform and transparent. Their viscosity, storage modulus G’, and loss modulus G” increased significantly upon increasing the content of Laponite and the dose of monomers. They showed tunable adhesion by changing the dose of Laponite and monomers, as well as pH as determined by 180° peel strength measurement. The maximal adhesion was shown when reaching a balance between cohesion and fluidity. A home-made JKR instrument was employed to study the surface adhesion behavior of the NC gels. The combination of peel strength, rheology, and Johnson-Kendall-Roberts (JKR) measurements offers the opportunity of insight into the mechanism of adhesion of hydrogels. The NC gels with tunable adhesion should be ideal candidates for dental adhesive, wound dressing, and tissue engineering.