Solvophobic and Solvophilic Effects on the Potential of Mean Force between Two Nanoparticles in Binary Mixtures

We apply the integral equation theory to study the solvent-induced potential of mean force between two passivated nanoparticles in binary mixtures. We consider a particular model mixture involving two solvent components, where the nanoparticle is weakly solvophilic with respect to one component and solvophobic with respect to the other one. We show that the increase in the mole fraction of the second component results in a more attractive interaction potential between two nanoparticles due to the enhancement of the solvophobic attraction between them, and that these changes in the interaction potential are comparable to the thermal energy. Our results indicate the possibility of using cosolvents in order to tune the degree of solvation and the interaction strength between nanoparticles in solution.