(560f) Pulsed Field Gradient NMR Studies of Organocation – Silica Nanoparticle Mixtures

The nucleation and growth of high-silica zeolites in the presence of organocations is an extremely important, but as yet unresolved process in the zeolite science community. While many labs have investigated these systems, particularly TPAOH/TEOS/water mixtures, using methods including scattering, electron microscopy, and calorimetry, the organocation-silica interactions are poorly understood. This presentation will summarize our recent efforts using pulsed-field gradient (PFG) NMR methods to investigate this issue. In short, our work to date shows that by monitoring how the self-diffusion coefficient of the organocation changes with solution conditions, it is possible to measure quantities such as the free energy of adsorption of the organocations on the silica nanoparticle surfaces. We will present results for a series of TAAOH-silica mixtures, as well as results for a series of mixtures containing ?TPA-mimics' and silica.