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Assembly of complex colloidal structures using critical Casimir forces.

  • Supervisor: Prof. dr. Peter Schall
  • Research Team: Simon Stuij
  • Goal: To create complex structures in a colloidal material using patchy particles and the critical Casimir force interaction.
  • Info: P. Schall, S.G. Stuij

Most current colloidal materials have either a simple liquid structure, a close packed crystal structure or an arrested gel or glass structure. We are interested in developing colloidal materials with more controllable structures as they have potentially unique and useful macroscopic properties e.g. structural color and optical bandgaps. Moreover the availability and the control of a diverse set of local colloidal structures is a prerequisite for more distant but far reaching ideas e.g. colloidal machines. Our approach towards achieving these complex structures is by using site-specific ‘patchy’ colloids which can form bonds only at certain angles with each other. Additionally, we use a temperature-controlled interaction called the critical Casimir interaction which makes these bonds fully reversible upon raising and lowering the temperature. This interaction has the added advantage of allowing us to study in detail the assembly of the structured state from the disordered state. It also may allow different stable complex structures at different temperatures and to switch between them, this could potentially be used to design temperature tuneable optical filters.