Designer Colloids

Speaker: Dr Martin Buzza MInstP, University of Hull

Colloids are small particles suspended in a liquid and they are important for many practical applications (e.g., paints, inks, creams, ketchup, milk, blood etc.). Although colloids are much larger than atoms, they are often small enough to be perturbed by collisions from surrounding liquid molecules and execute a perpetual, random motion known as Brownian motion. This means that they can exert pressure on any walls that confine them, spontaneously self-assemble into crystal structures etc., and therefore effectively behave like ‘big atoms’. However, unlike atoms where the interactions are pre-defined, the interactions between colloidal particles can be easily tuned, allowing us to control the large-scale structure of colloidal suspensions through relatively modest modifications of the colloidal particles themselves or their environment. In this sense, colloids are ideal ‘designer materials’, allowing us to design and make new structures and materials for different applications. In this talk, I will focus on colloids adsorbed at liquid interfaces, which provide exciting opportunities for creating two dimensional (2D) materials. I will show that these colloidal 2D materials are very versatile, as the electrostatic, capillary and elastic interactions between the colloids can be tuned to create a rich variety of structures, including hexagonal, cluster phases, honeycombs and quasicrystals (exotic non-periodic crystal structures), see for example Figure 1. 

Figure 1 (Top row) Electron microscope images of complex cluster and chain phases formed by core-shell particles at an air/water interface at different area fractions of the particles; (Bottom row) Corresponding computer simulations of the same system. (from J. Menath, J.L. Eatson, R. Brilmayer, A. Andrieu-Brunsen, D.M.A. Buzza and N. Vogel, PNAS, 2021, 118, e2113394118)

Venue Information

The lecture will take place on Wednesday 26 February at 16:30. There will be free biscuits and cake from 16:00. The lecture will take place at the University of Leeds in the Sir William Henry Bragg Building, Lecture Theatre Gr.25.