Supracolloidal Self-Assembly of Micro-Hosts and -Guests on Substrates

In this paper, we demonstrate a microcolloidal analogue of supramolecular host–guest system consisting of polymer microrings as micro-hosts and spherical particles as micro-guests. Polystyrene microrings with accurately controlled hollow cavities are fabricated by a two-step selective plasma etching method. The diameter and depth of the hollow ring can be controlled by different etching stage. The surface charge of microrings can be modified through sulfonation and/or layer-by-layer deposition of polyelectrolytes. Through electrostatic interactions, polystyrene microrings on substrates are used as micro-hosts to capture oppositely charged spherical micro-guests with assembly yields up to 98.7%. The micro-host/guest compounds are found to be stabled in aqueous solution even after peeled off from the substrate.