Investigating adsorption to soft-matter interfaces with second harmonic scattering Erika J. Riffe 1 , Richard J. Saykally 1,2 1 Department of Chemistry, University of California, USA, 2 Chemical Sciences Division, Lawrence Berkeley National Lab, USA Aqueous interfaces govern many important processes, e.g. water purification. Developing an understanding of ion and molecule adsorption to interfaces used for water filtration can assist the fabrication of better filtration systems. Second Harmonic Scattering spectroscopy (SHS) can be used to probe buried interfaces of model systems in situ . 1 Information including adsorption kinetics, particle size and shape, and molecular orientation of adsorbing species can all be determined from polarization and angle-resolved SHS measurements. 2 The Gibbs- free energy of adsorption of relevant ions and molecules to a variety of interfaces can provide a detailed picture of the adsorption processes. Methods such as competitive displacement are utilized to determine the adsorption of such molecules that do not possess a transition at the incident or second-harmonic frequencies. 3 Molecular orientation information can be used to infer the dominant molecular interactions occurring at each interface. 2 The development of these techniques to probe colloidal samples such as polymers, porous silica nanoparticles, and metal-organic frameworks (MOFs) will be discussed. Further, the effect of ion strength and pH will be considered. References 1. S. Roke, G. Gonella. Nonlinear Light Scattering and Spectroscopy of Particles and Droplets in Liquids. Annu. Rev. Phys. Chem. 2012, 63 , 353-78. 2. A.G.F. de Beer, S. Roke. Obtaining molecular orientation from second harmonic and sum frequency scattering experiments in water: Angular distribution and polarization dependence. J. Chem. Phys . 2010, 132 , 234702. 3. W.T.S. Cole, H. Wei, S.C. Nguyen, C.B. Harris, D.J.Miller, R.J. Saykally. Dynamics of Micropollutant Adsorption to Polystyrene Surfaces Probed by Angle-Resolved Second Harmonic Scattering. J. Phys. Chem. C 2019, 123 , 14362-14369.
P35
© The Author(s), 2023
Made with FlippingBook Learn more on our blog