(678a) Competitive Adsorptionat Interfaces: Insights from Experiments and Simulations

Colloidal formulations contain a variety of surface-active compounds, including molecular surfactants, low molecular-weight compounds, fragrances, particles and nanoparticles, and other components, for example impurities. A variety of applications, ranging from cleaning to wetting to adhesion, depend on the preferential adsorption of various compounds on selected surfaces and interfaces. In this presentation, we will review a series of experimental and computational investigations conducted for selected systems to probe and quantify competitive adsorption at selected interfaces. Experimentally, focus will be on data obtained using the quartz crystal microbalance with dissipation monitoring (QCM-D). These experiments were conducted for single surfactants in the presence of low molecular weight compounds (e.g., impurities or co-surfactants), as well as for surfactant mixtures, and for surfactant systems competing with antibiotics for adsorption on plastic surfaces. Computationally, synergistic studies were conducted to elucidate the mechanisms responsible for the experimental observations just summarized, as well as to probe the adsorption of surfactant mixtures at liquid-liquid interfaces. The practical and environmental implications of the results will be briefly discussed during the presentation.