Improved Parametrization for Extended Derjaguin, Landau, Verwey, and Overbeek Predictions of Functionalized Gold Nanosphere Stability

Surface chemistry variations on alkanethiol-modified gold nanoparticles (i.e., packing density, tilt angle, and composition) influence their function in nanotechnology-based applications. Accurate theoretical predictions of the stability of functionalized nanoparticles enable guided design of their properties but are often limited by the accuracy of the parameters used as model inputs. These parametrization limitations for the extended Derjaguin, Landau, Verwey, and Overbeek (xDLVO) theory are overcome using a size-dependent Hamaker constant for gold, interfacial surface potentials, and the tilt angles of self-assembled monolayers (SAMs), which improve the predictive power of xDLVO theory for modeling nanoparticle stability. Measurements of the electrical properties of gold nanoparticles functionalized with a series of thiolated acids of differing ligand lengths and SAM tilt angles validate the predictions of xDLVO theory using these new parametrizations, illustrating the potential for this approach to improve the design and control of the properties of functionalized gold nanoparticles in various applications.