Towards Colloids for Host-Guest Complexation

Abstract

In this research the possibilities were explored to equip colloidal particles with host-guest interactions. Host-guest interactions are a (macro)molecular phenomenon that involves the inclusion of a guest molecule by a larger host molecule. A well studied host is cyclodextrin, which forms inclusion complexes with a wide range of organic molecules with typical binding energies of several kBT. These relative mild interactions make this host-guest complexation interesting to apply on colloidal systems, since these systems are usually dominated by forces in the order of a few kBT. In order to design a system suitable for these interactions, a variety of colloids were equipped with different polymer brushes via a controlled surface initiated polymerisation technique. First it was shown that different particles could be obtained that are suitable for the growth of polymer brushes from the particles. Thereafter, particles with different polymers brushes and block-copolymers brushes were synthesized. It was shown that when these brushes contain reactive groups, they could be used for further modification. When two different particles were prepared, one equipped with host molecules and the other with guest molecules, colloidal aggregation was observed. This provides a proof of concept of for the use of host-guest interactions on a colloidal scale. Additionally, the stability of particles with different polymers and block-copolymers was investigated and an attempt was made to investigated the electrophoretic behavior of the particles but it was concluded that a more detailed investigation is required on this topic.