Dr. Martin Buzza from the Department of Physics and Mathematics of the University of Hull will give a seminar at the School of Mathematics and Physics, on Wednesday the 2nd of December 2015, 3 pm (room ENG209 in Engineering hub, building 13 on the uni map).

Complex behaviour of colloids adsorbed at liquid interfaces

The behaviour of colloids adsorbed at liquid interfaces has attracted growing attention in the last two decades due to their practical importance in the context of particle stabilised emulsions (so called Pickering emulsions). However from a scientific point of view, particles at liquid interfaces also serve as beautiful model systems for a 2D colloidal fluid. In this talk, I will first discuss the interaction between colloidal particles at a liquid interface and show that they are markedly different from those of a bulk colloidal suspension and how they can be tuned by changing the wettability of the particles. Indeed there is still considerable debate in the literature regarding the exact nature of these interactions and I will describe our attempts to measure these interactions [1]. I will then discuss the self-assembly of binary mixtures of hydrophobic and hydrophilic colloidal particles adsorbed at oil/water interfaces. Experimentally, we find that by tuning the interactions, composition and packing geometry of the mixed monolayer, a rich variety of two-dimensional super-lattice [2] and cluster [3] structures are formed which are stabilised by strong electrostatic interactions mediated through the oil phase. The 2D structures obtained are in excellent agreement with zero temperature lattice sum calculations [2-4], indicating that the self-assembly process can be effectively controlled for the creation of novel 2D structures and materials.

[1] L. Parolini, A.D. Law, A. Maestro, D.M.A. Buzza, P. Cicuta, J. Phys.: Condens. Matter, 27, 194119 (2015)

[2] A.D. Law, D.M.A. Buzza, T.S. Horozov, Phys. Rev. Lett., 106, 128302 (2011)

[3] A.D. Law, M. Auriol, D. Smith, T.S. Horozov, D.M.A. Buzza, Phys. Rev. Lett., 110, 138301 (2013)

[4] A.D. Law, T.S. Horozov, D.M.A. Buzza, Soft Matter, 7, 8923 (2011)