title: Multicompartmental Janus microbeads from branched polymers by single-emulsion droplet microfluidics.
abstract: We describe a versatile and facile route for the preparation of Janus microbeads using single emulsion droplet-based microfluidics, in which water droplets that contain a mixture of branched poly(N-isopropylacrylamide)-co-(poly(ethylene glycol)diacrylate)-co-(methacrylic acid) and colloidal particles form the basis of our approach. The colloidal particles, poly(methyl methacrylate) microspheres or titanium dioxide particles, and iron oxide nanoparticles are spatially positioned within the water droplets through gravity and an externally applied magnetic force, respectively. Evaporation of water leads to gel formation of the branched copolymer matrix as a result of physical cross-linking through hydrogen bond interactions, fixing the spatial position of the colloidal particles. The thermo- and pH-responsive nature of the branched poly(N-isopropylacrylamide) (PNIPAm)-based copolymer allows for the disintegration of the polymer network of the Janus microbeads and a triggered release of the colloidal content at temperatures below the lower critical solution temperature (LCST) and at increased pH values.
authors.affiliation: Department of Chemistry, University of Warwick , Coventry CV4 7AL, U.K.
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Chen
authors.forename: Gabit
authors.initials: G
authors.lastname: Nurumbetov
authors.forename: Rong
authors.initials: R
authors.lastname: Chen
authors.forename: Nicholas
authors.initials: N
authors.lastname: Ballard
authors.forename: Stefan A F
authors.initials: SA
authors.lastname: Bon
mesh_terms: D004655:Emulsions / Q000737:chemistry; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D058185:Magnetite Nanoparticles / Q000737:chemistry; D044085:Microfluidics / Q000295:instrumentation; D010316:Particle Size; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D004655:Emulsions; D058185:Magnetite Nanoparticles; D011108:Polymers