Evanescent-wave dynamic light scattering at an oil-water interface: Diffusion of interface-adsorbed colloids

Stocco, Antonio; Mokhtari, Tahereh; Haseloff, Günter; Erbe, Andreas; Sigel, Reinhard

doi:10.1103/PhysRevE.83.011601

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Journal article

Evanescent-wave dynamic light scattering at an oil-water interface: Diffusion of interface-adsorbed colloids

Stocco, Antonio Max Planck Institute of Colloids and Interfaces, Golm, Germany
Mokhtari, Tahereh Adolphe Merkle Institute, Fribourg, Switzerland
Haseloff, Günter Max Planck Institute of Colloids and Interfaces, Golm, Germany
Erbe, Andreas Max Planck Institute of Colloids and Interfaces, Golm, Germany - Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany.
Sigel, Reinhard Adolphe Merkle Institute, Fribourg, Switzerland

13.01.2011

Published in:

Physical Review E. - 2011, vol. 83, no. 1, p. 011601

English A light-scattering goniometer for evanescent-wave dynamic light scattering (EWDLS) measurements at a liquid-fluid interface is introduced, and used for measurements on two charge-stabilized polystyrene colloid systems adsorbed to alkane-water interfaces. The goniometer allows an independent variation of the penetration depth and the scattering vector components parallel and perpendicular to a liquid-fluid interface. The possible illumination geometries are compared. Ellipsometry at the liquid-fluid interface is implemented as a complementary tool. In EWDLS measurements, the absence of diffusive motion perpendicular to the interface is demonstrated, which confirms the adsorption of the particles. The two-step decay of the autocorrelation function is interpreted in terms of diffusion within a two-dimensional interface lattice of colloidal particles, stabilized by repulsive electrostatic interactions, and a desorption process. A significant slowing down of the in-plane diffusion of the colloids as compared to the bulk diffusion is observed.

Faculty

Faculté des sciences et de médecine

Department

AMI - Soft Nanoscience

Language