Diffusion of gold nanoparticles in porous silica monoliths determined by dynamic light scattering

Hypothesis: The applicability of the dynamic light scattering method for the determination of particle dif-fusivity under confinement without applying refractive index matching was not adequately explored so far. The confinement effect on particle diffusion in a porous material which is relevant for particle chro-matography has also not yet been fully characterized.Experiments: Dynamic light scattering experiments were performed for unimodal dispersions of 11-mercaptoundecanoic acid-capped gold nanoparticles. Diffusion coefficients of gold nanoparticles in por-ous silica monoliths were determined without limiting refractive index matching fluids. Comparative experiments were also performed with the same nanoparticles and porous silica monolith but applying refractive index matching.Findings: Two distinct diffusivities could be determined inside the porous silica monolith, both smaller than that in free media, showing a slowing-down of the diffusion processes of nanoparticles under con-finement. While the larger diffusivity can be related to the slightly slowed-down diffusion of particles in

Automated summary

The applicability of dynamic light scattering for determining particle diffusivity under confinement without refractive index matching has not been fully explored. Furthermore, the effect of confinement on particle diffusion in porous materials relevant to particle chromatography has not been fully characterized.