Untangling superposed double layer and structural forces across confined nanoparticle suspensions

Colloidal suspensions in confined geometries

In the presence of geometric confinements such as topographically patterned surfaces, strong light fields, or channels the phase behavior and the dynamical properties of colloidal suspensions are strongly modified in comparison to the bulk properties. Because such geometric confinements play an important role in many physical, biological and chemical processes, investigations of the properties ...

Effects of image charges on double layer structure and forces.

The study of the electrical double layer lies at the heart of soft matter physics and biophysics. Here, we address the effects of the image charges on the double layer structure and forces. For electrolyte solutions between two neutral plates, we show that depletion of the salt ions by the image charge repulsion results in short-range attractive and long-range repulsive forces. If cations and a...

Thermal conductivity of nanoparticle suspensions

We describe an optical beam deflection technique for measurements of the thermal diffusivity of fluid mixtures and suspensions of nanoparticles with a precision of better than 1%. Our approach is tested using the thermal conductivity of ethanol-water mixtures; in nearly pure ethanol, the increase in thermal conductivity with water concentration is a factor of 2 larger than predicted by effectiv...

Nanoparticle embedded double-layer coating for daytime radiative cooling

Probing the double layer: effect of image forces on AFM.

Force probes such as AFM tips or laser trap latex beads have a dielectric constant much less than that of the water that they displace. Thus when a probe approaches a charged surface under water it will be repelled simply based upon the image forces, and these can be of nN magnitude.