The behavior of hydrophobic-core/hydrophilic-shell structured microgels at an interface: From Mickering emulsion to colloidosomes with dual-level controlled permeability

Abstract

A bottom-up approach was empolyed to prepare colloidosomes with dual-level controlled permeability. Starting from the monodisperse poly-2,2,2-trilfuoroethyl methacrylate (PTFMA) core, different size of microgels were obtained by introducing varying thickness of the Poly(N-isopropylacrylamide) (P(NIPAM-co-AAc)) shell. The effects of core on the mechanical property of microgels and their behavior at oil/water interface in Mickering emulsion were carefully studied. The colloidosomes were then obtained by the “locking” the interfaical microgels in the Mickering emulsion. The release of model drug FITC-Dex from colloidosomes was examined in selected media and the controllable release was achieved by pH (coarse level) and the ratio of the shell to core in the microgels (fine level). The dual-level controlled permeability of colloidosomes enables the high precision for pH triggered drug release system. It is the first demonstration on the permeability control of colloidosomes can be achieved by size control on shell and core of microgels owing to the core hydrophobicity and the shell hydrophilicity. Both convenience and precision on permeability control of colloidosomes were improved in this way due to the mature size control technology in the microgels synthesis.