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.