(56a) Biosurfactants in Aqueous Solution: Self-Assembly and Surface Adsorption

Biosurfactants are naturally occurring amphiphiles that reduce interfacial tension in water-oil mixtures. On the basis of their ability to mobilize and disperse hydrocarbons, biosurfactants are involved in the bioremediation of oil spills, and are being actively pursued as alternatives to synthetic surfactants in cleaning, personal care, and cosmetic products. We examine here the micellization of mono-rhamnolipids and di-rhamnolipids in aqueous solutions and their adsorption on solid surfaces, and discuss the effects of rhamnolipid headgroup, rhamnolipid purification, and presence of salt in water. Further, we compare the rhamnolipid solution and surface association behavior to that of synthetic surfactants. An improved fundamental understanding of biosurfactant self-assembly and adsorption properties is important for their utilization in environmental and consumer products applications.