Layer-by-Layer (LbL) assemblies of poly(allylamine hydrochloride) (PAH) and hyaluronic acid (HA) were fabricated in order to study their wet adhesive behavior. The film characteristics were investigated by AFM, QCM and DPI to understand the inherent surface structures during the assembly process. Adhesion of these systems was evaluated with colloidal probe AFM to understand the correlation between the structure of the film and the energy required to separate these LbL assemblies. We describe how the conditions of the LbL fabrication can be varied to control the adhesion between films. The characteristics of the film formation are examined as a function of ionic strength during the film formation. The dependence on contact time and LbL film thickness on the critical pull-off force and work of adhesion are discussed. Specifically, by introducing sodium chloride (NaCl) in the assembly process, the pull off force can be increased by a factor of 10 and the work of adhesion by two orders of magnitude. Based on these results we discuss how the fabrication procedure can create low or highly adhesive interfaces.
torbjorn@forceit.eu
