Chirality is abundant in nature and plays an important role in biology, chemistry and physics. Symmetry breaking and handedness establishment lead to essentially novel phenomena such as coupling of the translational degrees of freedom and self-propelling.
Within the proposed research, we shall develop novel synthesis methods to fabricate colloids with chiral shape resembling that of DNA. To this end we shall use the molecular/colloidal co-assembly method recently discovered by us. In this approach molecular self-assembly of surfactant (SDS) and cyclodextrin (β-CD) complexes yields hollow tubes of a well-defined size, which confine colloidal particles in their interior. The chiral assemblies are then formed due to simple geometrical restrictions. The co-assembly approach will be further optimised to increase the yield of chiral assemblies and to gain better control of their geometrical parameters. This will be achieved by varying details of the SDS@2β-CD system as well as by testing other molecular tube-forming systems. The crucial step of this proposal is to develop synthesis methods to fix the generated dynamic colloidal assemblies in order to fabricate chiral colloidal particles, which will be stable after the cylindrical confinement is removed.
The synthesised particles will then be used to study the effects of chirality on their anisotropic Brownian and induced motion, self-propelling, etc. We shall subsequently develop separation techniques to yield monodisperse fractions with well-defined handedness. We shall study the interactions of chiral colloids with liquid-crystalline chiral media such as the cholesteric phase, which can provide new means to influence the latter with possible novel applications in the display technology and photonics. Furthermore, we shall investigate the effects of the particle chirality on their pair-wise interactions such as excluded volume, hydrodynamic and screened electrostatic, which can play a role for biological macromolecules. Finally, studies of the self-assembly of chiral colloids will be initiated.

• prof. dr. A.P. (Albert) Philipse

There is a need for chiral structures on colloidal length scales, for example, to control the optical properties of materials. Although examples exist in nature of materials that self-assemble into chiral structures, the mechanisms for the transfer of chirality on a molecular length scale to the colloidal length scale are often unclear. The objective of this proposal is to study chiral self-assembly on a colloidal length scale in confinement. We will focus on the self-assembly of cellulose, known to show a chiral nematic phase, in the presence of temperature reversible supramolecular microtubules of sodium dodecyl sulphate (SDS) and β-cyclodextrin (β-CD). The microtubules are a versatile model for confining pores, while allowing in-situ measurement of the structure and dynamics of the co-assembly. Moreover, we can modify the microtubules using conventional wet-chemical methods...

This project was developed by Jasper Landman, the winner of the Debye graduate programme, who is now working on it as a PhD student. Part of the project is co-funded by the ESRF. 

The objective of the proposed research is to develop colloidal particles with adjustable valence, and study their aggregation properties. Here, ‘valence’ is defined broadly as a measure for the potential number of bonds formed with other colloids, and corresponds to the number of sticky patches on the surface of a colloidal particle. We have recently developed a method to produce colloidal particles with adjustable number of patches and angles between them, see [Kraft et al., JACS 131, 1182, (2009); Soft Matter DOI: 10.1039/b910593j (2009)]. We propose to exploit and explore this unique system by making the patches sticky... 

I was co-applicant of this project (PI: Willem Kegel). I supervised Antara Pal and acted as an advisor in the PhD project of Joost Wolters.

• dr. J. (Jan) Groenewold