title: Facile spray-drying assembly of uniform microencapsulates with tunable core-shell structures and controlled release properties.
abstract: Microencapsulates with defined core-shell structures are of interest for applications, such as controlled release and encapsulation, because of the feasibility of fine-tuning individual functionalities of different parts. Here, we report a new approach for efficient and scalable production of such particles. Eudragit RS (a co-polymer of ethyl acrylate, methyl methacrylate, and a low content of methacrylic acid ester with quaternary ammonium groups) was used as the main shell component, with silica as the core component, formed upon a single-step spray-drying assembly. The method is capable of forming uniform core-shell particles from homogeneous precursors without the use of any organic solvents. Evaporation-induced self-assembly attained the phase separation among different components during drying, resulting in the core-shell spatial configuration, while precise control over particle uniformity was accomplished via a microfluidic jet spray dryer. Direct control over shell thickness can be achieved from the ratio of the core and shell ingredients in the precursors. A fluorescent compound, rhodamine B, is used as a highly water-soluble model component to investigate the controlled release properties of these microencapsulates, with the release behaviors shown to be significantly dependent upon their architectures.
authors.affiliation: Department of Chemical Engineering, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Liu
authors.forename: Winston Duo
authors.initials: WD
authors.lastname: Wu
authors.forename: Cordelia
authors.initials: C
authors.lastname: Selomulya
authors.forename: Xiao Dong
authors.initials: XD
authors.lastname: Chen
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002214:Capsules / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D003692:Delayed-Action Preparations; D006868:Hydrolysis; D008027:Light; D055616:Microtechnology / Q000379:methods*; D010316:Particle Size; D012542:Scattering, Radiation; D012821:Silanes / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D002214:Capsules; D020099:Coated Materials, Biocompatible; D003692:Delayed-Action Preparations; D012821:Silanes; D014867:Water; C050528:Eudragit RS; C040733:tetraethoxysilane