Abstract:
Present project aims a molecular fabrication approach to study the behaviour of foulants on planar surfaces at specifically controlled pH for the polymeric thin films coatings fabricated by electrostatic layer-by-layer (LBL) assembly methods. Copolymers of polymethyl methacrylate PMMA and Poly (acrylic acid) (PAA, a weak polyanion) were synthesized with various compositions as PMMA-co-AA 70, 50 and 30%. These are employed as polyanion with poly(diallyl dimethylammonium chloride) (PDADMAC, a strong polycation) were used to build up the bulk films. The PDADMAC and in certain cases PAH was applied as a top layer in bacterial adhesive thin films. Surface charge tuning was accomplished by controlling the level of ionization of the weak polyelectrolytes at different pH values and subsequent manipulation of the amount of polyelectrolyte deposited in the one preceding the last and last layers, respectively. The prepared films were investigated for their antimicrobial and bacterial surface characteristics and role of hydrophilic and hydrophobic characteristics were discussed. The fouling behaviour of bacteria on the LBL films with similar hydrophilicity and roughness but different surface charge densities was studied. Antimicrobial activity of coated glass slides was evaluated against Escherichia coli (E. coli, ATCC# 8739) and Staphylococcus aureus (S. aureus, ATTC# 6538). The switchable thin films coatings developed allows achieving optimal microbial growth both in terms of repelling and adhesion performances at the specific pH values of the environment. The surface characteristics of the foulants as well as the bacterial adhesive thin films can be used to switchable attach or repel and detect control concentration of bacterial strains.
