Liquid Crystal Colloids
Particle-laden flows are at the heart of many scientific and engineering applications, ranging from the dispersion of pollutants and rain formation in the atmosphere to pharmaceutical aerosols and industrial spray applications to geological sedimentation and combustion processes, and even planetary formation. Such flows consist of a continuous liquid host phase and dispersed particles.
While the movement of particles in isotropic fluids (such as water) has been studied extensively, much less studied are the dynamics and migration of particles in liquid crystalline host phases, whose internal structure offers additional possibilities in terms of elastic and order-driven control.
The video below shows an example of the behaviour of a particle within a nematic undergoing pressure-driven flow. The coloured rods are the director (the average molecular orientation) while the green isosurface denotes a region of low molecular order, associated with a defect in the director structure. Here we see that the particle initiates a transition from a `bend' state (where the director at the centre of the region is vertical, blue directors) to a 'splay' state (where the director at the centre of the region is horizontal, red directors).
This project is led by Dr Oliver Henrich at the University of Strathclyde and the key researcher is Magdalena Lesniewska, a postgraduate research student at Strathclyde.