| Electrostatic interactions in solution have been studied for over a century. During this time an enormous effort has been applied to understanding how charged particles interact when they are surrounded by an electric double layer (EDL) comprised of counterions and co-ions. Recently, synthetic procedures have been developed to produce nanoparticles (NPs) with well controlled shapes, sizes, and polydispersity that can be functionalized by adsorbing ligands in a self-assembled monolayer (SAM) on their surface. These monolayers can contain functional groups that can dissociate or adsorb ions, be oxidized or reduced, or reconfigure to change their dipole moment -- all of which influence the electrostatic potential around the particle and also the electrostatic interparticle interactions.;In this thesis I present a number of experimental examples supported by theoretical arguments where electrostatic interactions are used to either measure or control chemical, optical, or electronic properties of the systems. The initial group of examples focuses on the reactivity of ligands adsorbed to nanoparticle surfaces, followed by a group of examples in which "switchable" molecules -- including Stoddart-type mechanically interlocked molecules, their precursors, and light sensitive azobenzene moieties -- are used to selectively assemble NPs into larger structures and control the UV-vis absorption of the system. The characteristic length scale of the experimental systems is then increased to examine the conductance of thin films of "ionic" NPs. Finally, electrostatic interactions are examined on a macroscopic scale by characterizing contact electrification between nominally identical surfaces and the use of electric field gradients to assemble millimeter scale dielectric particles. Taken as a whole, these examples show that electrostatic interactions can be used to control the behavior of systems with length scales from nanometers to millimeters. |
