Quantitative measurement of core coverage in core-shell particles by solid-state H-1 NMR spin-diffusion experiments

The shell material core coverages of two-phase core-shell particles are det ermined quantitatively by NMR spin-diffusion experiments. A simple relation is derived between the specific surface (ratio of core surface and core vo lume) and the core coverage of acrylic core-shell particles in the solid st ate. Through calibration with a reference sample of known core coverage, th e core coverage of the other samples can then be evaluated. The values of c ore coverages determined by spin-diffusion become more accurate as the core coverage becomes smaller. In a series of poly(methyl methacrylate) (PMMA) and poly(butyl acrylate) core-shell latices, the core coverage was found to vary between 43 and 80%. Additionally, information about the global partic le morphologies is derived from a quantitative comparison of the specific s urface and the particle diameter measured by dynamic light scattering.