Direct Measurement of Surface Forces in Liquids-Measurement of Hydrophobic Attraction-

Direct measurement of thermophoretic forces.

We study the thermophoretic motion of a micron sized single colloidal particle in front of a flat wall by evanescent light scattering. To quantify thermophoretic effects we analyse the nonequilibrium steady state (NESS) of the particle in a constant temperature gradient perpendicular to the confining walls. We propose to determine thermophoretic forces from a "generalized potential" associated ...

Direct Measurement of Colloidal Forces in an Anisotropic Solvent

We present a new method to measure attractive interactions between colloidal particles, and determine the nature of the attraction between particles suspended in a nematic liquid crystal. We confine droplets filled with ferrofluid to a thin layer and apply a magnetic field to induce dipole moments that drive the droplets apart. When the field is removed, the attractive interactions pull the dro...

Direct measurement of crystal surface stress.

Direct measurement of interaction forces between charged multilamellar vesicles†.

Depletion-attraction induced adhesion of two giant (∼ 40 μm), charged multilamellar vesicles is studied using a new Cantilevered-Capillary Force Apparatus, developed in this laboratory. The specific goal of this work is to investigate the role of dynamics in the adhesion and de-adhesion processes when the vesicles come together or are pulled apart at a constant velocity. Hydrodynamic effects ar...

Direct measurement of entropic forces induced by rigid rods.

We present the first direct depletion potential measurements for a single colloidal sphere close to a wall in a suspension of rigid colloidal rods. Since all particle interactions are as good as hard-core-like, the depletion potentials are of entirely entropic origin. We developed a density functional theory approach that accurately accounts for this experimental situation. The depletion potent...