The orientation and charge of water at the hydrophobic oil droplet-water interface.

Electrophoretic mobility does not always reflect the charge on an oil droplet.

Electrophoresis is widely used to determine the electrostatic potential of colloidal particles. Oil droplets in pure water show negative or positive electrophoretic mobilities depending on the pH. This is commonly attributed to the adsorption of hydroxyl or hydronium ions, resulting in a negative or positive surface charge, respectively. This explanation, however, is not in agreement with the d...

The measurement of droplet size distribution of water-oil emulsion through NMR method

The effects of water/oil volume ratio, type and concentration of demulsifier, water salinity and mixing speed on the average water droplets size in water-oil emulsion are evaluated at different times through NMR measurements.The type and concentration of demulsifier have the greatest effects on the average droplet size with 38% and 31.5%, respectively. The water/oil volume ratio, water salinity...

Janus silica film with hydrophobic and hydrophilic surfaces grown at an oil–water interface†

We report a new methyltrimethoxysilane (MTMS) based route to growing a Janus silica film at the oil–water interface, which upon drying shows anisotropic wetting by water on its two surfaces. The contact angle of water on the surface grown in contact with the oil-side is found to be 150 , but it is much smaller, 65 , on the side which grew in contact with the aqueous phase. This large difference...

Electro-Coalescence of an Aqueous Droplet at an Oil–Water Interface with an Investigation of Secondary Droplets Formation

Effect of Bubble/Droplet Morphology and Slippage on Attachment Induction Time in Deoiling Flotation Process

A modified model has been analytically developed to describe the induction time of an elliptic air bubble in contact with an elliptic hydrophobic oil droplet. The role of hydrophobicity was revealed in the slippage of liquid over the surfaces of bubble and droplet. In this condition, the analytical relationships for pressure distribution and consequently hydrodynamic resistance force through th...