We study the self-assembly of mixed monolayers of hydrophobic and hydrophilic colloidal particles adsorbed at oil/water interfaces both experimentally and theoretically. Experimentally, we find that by tuning the interactions, composition and packing geometry of the mixed monolayer, a rich variety of two-dimensional super-lattice and cluster structures are formed which are stabilised by strong electrostatic interactions mediated through the oil phase [1,2]. The 2D structures obtained are in excellent agreement with zero temperature lattice sum calculations, indicating that the self-assembly process can be effectively controlled [1-3]. Monte Carlo simulations further reveal that the melting behaviour of these super-lattice structures proceeds via a multi-stage process, with melting temperatures that have a very strong and non-monotonic dependence on composition [3].
[1] A.D. Law, D.M.A. Buzza, T.S. Horozov, Phys. Rev. Lett., 106, 128302 (2011) [2] A.D. Law, M. Auriol, D. Smith, T.S. Horozov, D.M.A. Buzza, submitted [2] A.D. Law, T.S. Horozov, D.M.A. Buzza, Soft Matter, 7, 8923 (2011)
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