title: PS/CTAB/silica composites from room temperature polymerization of high internal phase emulsion gels.
abstract: Polystyrene (PS)/cetyltrimethylammonium bromide (CTAB)/silica composites were prepared by CTAB-catalyzed in-situ polymerization of high internal phase emulsion gels (HIPE gels) at room temperature. The room temperature approach in HIPE gels yielded mono-dispersed PS/CTAB/silica spherical composite particles with sizes of 121 and 155nm. The complex microscopic internal structures of these particles were determined with the use of temperature-modulated differential scanning calorimetry (TMDSC). CTAB, in particular, was identified in different environments within the composite particles based on its different crystallization temperatures observed on cooling: a thin layer at the surface of the fumed silica (TC,CTAB=74°C), multilayers (TC,CTAB=82°C), and a mixed PS/CTAB shell (TC,CTAB=65°C). The amounts of each component were estimated from the enthalpies of the crystallization. The PS/CTAB mixed shell contained CTAB on the surface of the particle plus internal CTAB domains.
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Tan
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Brewer Science Inc., 2401 Brewer Drive, Rolla, MO 65401, USA.
authors.forename: Gu
authors.initials: G
authors.lastname: Xu
authors.affiliation: Department of Mechanical Engineering, Purdue School of Engineering and Technology, Indiana University - Purdue University Indianapolis, IN 46202, USA.
authors.forename: Zhe-Fei
authors.initials: ZF
authors.lastname: Li
authors.affiliation: Department of Chemical Engineering, Ben-Gurion University of the Negev, P.O. Box 653, 84105 Beer-Sheva, Israel.
authors.forename: Oren
authors.initials: O
authors.lastname: Regev
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA.
authors.forename: Madhubhashini
authors.initials: M
authors.lastname: Maddumaarachchi
authors.affiliation: Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA. Electronic address: fblum@okstate.edu.
authors.forename: Frank D
authors.initials: FD
authors.lastname: Blum
keywords: Cetyltrimethylammonium bromide; Differential scanning calorimetry; Free radical polymerization; High internal phase emulsion gels; Polymeric composite nanoparticles; Surfactant catalysis