Potential-Controlled Tensiometry: A Tool for Understanding Wetting and Surface Properties of Conductive Powders by Electroimbibition.

Potential-controlled tensiometry is a voltage-induced method which enables measuring the contact angle between a powder bed and a liquid medium through the capillary rise method. This analytical tool provides a fine-grained technique for understanding wetting behavior of powders as well as solid surfaces in connection with the application of an electrical potential. In this work, the powder bed was brought into contact with an aluminum rod connected to a portable lightweight DAC-module (digital to analog converter) powered by a lithium-polymer battery (LiPo). The presented analytical device can be charged up to ±1000 mV. Both the power source and the DAC-module are lightweight in order to be conveniently attached to a force tensiometer without incorporating complex wiring. In this setup, we tested multiwall carbon nanotubes (MWCNT) and glassy carbon particles. An influence of the potential on the wetting behavior of glassy carbon particles is observed which demonstrates the working principle of the device. Surprisingly, no significant effect of the potential on the wetting behavior of MWCNT is indicated in the range studied. This technique can be a valuable tool to analyze the effect of changing surface properties applying electrical gradients on materials.