(473h) Self-Assembly and Foaming in Mixtures of Fatty Acid and Silica Nanoparticles | AIChE

(473h) Self-Assembly and Foaming in Mixtures of Fatty Acid and Silica Nanoparticles


Bharti, B. - Presenter, Louisiana State University
Ma, Y., Louisiana State University
Wu, Y., Louisiana State University
Shelton, W. A. Jr., Louisiana State University
Lee, J. G., Louisiana State University
The crucial roles of the ionization state and counterion’s presence on the phase behavior of fatty acid in aqueous solutions are well established. However, the effects of counterion on the adsorption and morphological state of fatty acid on nanoparticle surfaces are largely unknown. This knowledge gap exists due to the high complexity of the interactions between nanoparticles, counterions and fatty acid molecules in aqueous solution. In this study, we use adsorption isotherms, small angle neutron scattering, and all-atom molecular dynamic simulations to investigate the effect of addition of ethanolamine as counterion on the adsorption and self-assembly of decanoic acid onto aminopropyl modified silica nanoparticles. We show that the morphology of the fatty acid assemblies on silica nanoparticles changes from discrete surface patches to a continuous bilayer by increasing concentration of the counterion. This morphological behavior of fatty acid on oppositely charged nanoparticle surface alters the interfacial activity of the fatty acid-nanoparticle complex, and thus governs the stability of the foam formed by the mixture. Our study provides new insights into the structure-property relationship of fatty acid-nanoparticle complexes, and outlines a framework to program the stability of foams formed by mixtures of nanoparticles and amphiphiles.