Abstract:
Present project aims a molecular fabrication approach to study the behavior of fouling
organisms on planar surfaces at specifically controlled pH for the polymeric thin films
coatings fabricated by electrostatic layer-by-layer (LbL) assembly methods.
Poly(acrylic acid) (PAA, a weak polyanion) and poly(diallyldimethylammonium
chloride) (PDADMAC, a strong polycation) were used to fabricate the bulk films. The
weak Poly(allylamine hydrochloride) (PAH) was used as a top layer in bacterial
adhesive thin films. Surface charge tuning was accomplished by regulating 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 adhesive surface characteristics. The fouling behavior of
bacteria on the LbL films with almost comparable hydrophilicity and roughness but
varying 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 film coatings
developed allows achieving optimal microbial growth both in terms of repelling and
adhesion performances at the precise pH values of the environment. The surface
characteristics of the foulants as well as the bacterial adhesive thin films can be used
to switchably attach or repel and detect control concentration of bacterial strains.
