Solvation of Nanoscale Materials

The utility of colloidal nanomaterials in energy storage devices, high-definition displays, and industrial coatings depends on their solution processibility and stability. Traditional theories of solvation and colloidal stability, namely Derjaguin- Landau-Verwey-Overbeek (DLVO) and Flory-Huggins theories, describe classical approaches to solvation and colloidal sta- bility of hard-shell colloids and macromolecules, respectively. In contrast, the solution-state behavior of polymers, proteins, and related macromolecules must be understood in terms of solvent interactions, which become especially important due to the accessible cavities of hydrophobic and hydrophilic moieties in these systems. The colloidal stability of permanently porous materials, such as nanoparticles of metal-organic frameworks (nanoMOFs), on the other hand, challenges conventional notions of colloidal stability due to the presence of both internal and external surfaces, and because their external surfaces are mostly empty space. To develop nanoMOFs and other porous colloids into useful materials, we must understand the solvation of porous interfaces. Here, we discuss classical models of solvation and colloidal stability for non-porous and pseudo-porous (proteins and polymers) materials as a basis to propose that the colloidal stability of porous materials likely involves self- assembled solvation shells and strong solvent interactions with the molecular components of the nanomaterial.