Date: Wednesday 13th of January 2021, 13:30.
Location: Online (MS Teams meeting).

‘Are Langmuir trough studies useful? Unexpected emulsification behaviour using colloidal rods’

by Prof Paul Clegg, School of Physics and Astronomy, University of Edinburgh, Edinburgh, UK.

Abstract:

While studies carried out in a Langmuir trough have demonstrated that, at high surface pressure, rod-like colloidal particles flip from being parallel to being perpendicular to the liquid interface much less is known about the practical situation on the surface of a droplet or bubble. We present emulsification studies using colloidal rods and find that the rods are often shared between droplets forming a “bridge”. In a trough, it is the low aspect ratio rods which flip and the high aspect ratio rods which form bilayers; on the surface of a droplet we found that the high aspect ratio rods always bridge whereas the shorter rods are bistable. Hence, the behaviour of anisotropic particles in action is essentially opposite to expectations from trough studies.