Adsorption of alginic acid to titanium investigated using x-ray photoelectron spectroscopy and atomic force microscopy

X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) have been used to characterize the adsorption of alginic acid to titanium as a function of alginic acid solution pH. It was found that alginic acid adsorbs in greater quantity at acidic pH than at basic pH. The results provide evidence for an anion-exchange adsorption mechanism at weakly acidic pH. Addition of calcium chloride to the alginic acid solution results in a reduction of alginic acid adsorption at acidic pH and an increase at basic pH. This behavior can be explained by inhibition of anion exchange by the calcium cation at acidic pH and mediation of a bond between alginic acid and the titanium surface at basic pH. Elucidation of the adsorption chemistry of biofilm components to the surfaces of engineering materials is a prerequisite to developing surface modification strategies to reduce biofouling adhesion. Data presented herein can be used in the future as a baseline for comparison with data for such modified surfaces. Published in 2002 John Wiley Sons, Ltd.