Preparation of glycopolymer hollow particles by sacrificial dissolution of colloidal templates

In this paper, a simple method for fabrication of glycopolymer hollow particles was demonstrated. The P(St-CPEM)-g-PVBSAELA core–shell particles were prepared by emulsifier-free emulsion polymerization of styrene (St) with 2-chloropropionyloxyethyl methacrylate (CPEM) using potassium persulfate as an initiator, followed by surface-initiated activator generated electron transfer–atom transfer radical polymerization (AGET–ATRP) of a styrene derivative bearing a lactose residue, i.e., N-2-4-(vinylbenzenesulfonamido)ethyl lactobionamide (VBSAELA). Dynamic light scattering measurement showed that the P(St-CPEM)-g-PVBSAELA core–shell particles possess graft layers of ca. 160 nm in thickness on the P(St-CPEM) core of 455 nm in diameter. By taking advantages of large difference in solubility between the PSt-based core and the PVBSAELA shell, the submicron-sized PVBSAELA hollow particles were obtained through a selective extraction of the core part from the P(St-CPEM)-g-PVBSAELA particles in tetrahydrofuran. The hydrodynamic diameter of the resulting hollow particles decreased by 15% compared to that of the corresponding core–shell particles. Finally, the micron-sized, raspberry-shaped, PVBSAELA hollow particles were successfully fabricated by a sacrificial dissolution of the PSt-based components from the PVBSAELA-grafted, core/shell heterocoagulates.