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Materials from Colloidal Particles using Optical Fields

Presented by: 
Katherine Macmillan
Thursday 16th May 2019 - 16:40 to 17:00
INI Seminar Room 1
Session Title: 
A part of the celebration of Women in Materials Science (WMS)
Katherine A. Macmillan, Erick Sarmiento and Stefan U. Egelhaaf The interaction of light with colloidal particles has been widely exploited in optical tweezers [1]. In addition, multiple traps or extended potential energy landscapes (optical fields) have been applied using periodic interference patterns, speckle patterns created using ground glass and freely configurable patterns created using spatial light modulators [1, 2]. The capability of these optical potential energy landscapes to trap multiple colloidal particles in a designed structure has yet to be fully explored. In order to pursue this goal, here we study a two dimensional colloidal glass in a periodic potential. We find that a periodic potential with a periodicity commensurate with the lattice spacing for a hexagonally close packed array can induce the particles to crystallise. We have investigated the influence of parameters describing the potential on the formation of crystals from disordered structures. Upon the removal of the periodic potential, the colloidal particles can return to a more disordered state rendering the crystal structures only transient. The possibility of fixing this transient state by attaching the particles together has begun to be investigated. In the future, we aim to use optically-created potential energy landscapes to imprint a structure on a dispersion of colloidal particles that can be fixed by covalently bonding the particles together. [1] Richard D. L. Hanes, Matthew C. Jenkins and Stefan U. Egelhaaf, Review of Scientific Instruments, 2009, 80, 083703 [2] F. Evers, R.D.L. Hanes, C. Zunke, R.F. Capellmann, J. Bewerunge, C. Dalle-Ferrier, M.C. Jenkins1, I. Ladadwa, A. Heuer, R. Castañeda-Priego and S.U. Egelhaaf, European Physical Journal Special Topics, 2012, 222, 2995–3009
University of Cambridge Research Councils UK
    Clay Mathematics Institute London Mathematical Society NM Rothschild and Sons