title: Facile synthesis of core-shell/hollow anisotropic particles via control of cross-linking during one-pot dispersion polymerization.
abstract: Preparation of anisotropic particles based on seed phase separation involves multiple processes, and asymmetrical structures and surfaces cannot be produced when anisotropic shapes emerge. In conventional one-pot dispersion polymerization (Dis.P) using cross-linker, only spherical particles are prepared due to rapid and high cross-linking. Herein, monodisperse snowman-like particles with core-shell/hollow structures and partially rough surface were synthesized straightforward by a modified one-pot Dis.P, in which ethylene glycol and water (6/4, vol.) were used as medium, and ammonium persulfate (APS) aqueous solution, vinyl acetate (VA) and/or acrylic acid (AA), divinylbenzene (DVB) and styrene (St) were added at 6h. The cross-linking of growing particles was confined to exterior (forming cross-linked shell), and gel contents were low, leading to phase separation. Asymmetrical morphologies, structures, sizes and surface roughness were flexibly tuned by varying amounts of APS, VA and/or AA, water and DVB, and DVB adding speed. At low APS contents or high DVB amounts, the inhomogeneous cross-linking of head enabled its phase to separate, producing elongated head. With addition of VA and AA, phase separations inside head and body were induced, generating hollow structure. Adding DVB very slowly, nonlinear growth of third compartment occurred, forming bowed head.
authors.affiliation: Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China; State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China; State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China; State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: lyliu@mail.buct.edu.cn.
authors.forename: Lianying
authors.initials: L
authors.lastname: Liu
authors.affiliation: Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China; State Key Laboratory of Chemical Resource Engineering College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: yangwt@mail.buct.edu.cn.
authors.forename: Wantai
authors.initials: W
authors.lastname: Yang
keywords: Anisotropic particles; Controlled cross-linking; Core-shell and hollow structure; One-pot synthesis