How Does Charge Impact Surface Hydrophobicity?

Watch an 18-minute seminar exploring the complex relationship between surface charge and hydrophobicity at the molecular scale, presented by Camille Bilodeau from the University of Virginia at the Lennard-Jones Centre discussion group. Discover how molecular-scale hydrophobicity influences critical interfacial phenomena including adsorptive separations, fouling, colloidal assembly, and protein aggregation, while learning why hydrophobicity at molecular length-scales proves difficult to quantify and depends on surface chemistry and patterning in counterintuitive ways. Examine the methodology using two distinct approaches to measure surface hydrophobicity: Indirect Umbrella Sampling (INDUS) for directly measuring free energy of cavity formation, and spatial umbrella sampling to obtain free energy of binding for model hydrophobic solutes including gold nanoparticles functionalized with alkyl thiol SAMs and hydrophobin proteins. Understand how different positively charged groups such as ammonium versus guanidinium impact hydrophobicity differently due to variations in geometry, partial charge distribution, and hydrogen bond donor sites. Learn about the critical role of charged group spacing in modulating hydrophobicity, including the identification of specific "sweet spot" distances that maximize hydrophilicity. Gain insights into the theoretical foundation connecting adsorption energetics to de-wetting thermodynamics and how charged group chemistry and patterning influence molecular-scale hydrophobic behavior.