title: Facile method for preparing organic/inorganic hybrid capsules using amino-functional silane coupling agent in aqueous media.
abstract: A new and facile method for preparing microcapsules with 3-aminopropyltriethoxysilane (APTES)/alginate hybrid shell (AP-capsule) is proposed based on gelling and sol-gel processes. In this method, conventional capsules with alginate shells (Alg-capsule) are produced by dripping carboxymethyl cellulose solution containing calcium chloride into a sodium alginate solution. Subsequently, addition of the Alg-capsules to an aqueous APTES solution induces the formation of APTES/alginate hybrid shells. The optical observation shows that the texture of AP-capsules is more glossy and transparent than that of Alg-capsules. The surface morphology and elemental composition of microcapsules were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS). The results suggest that APTES molecules are incorporated to the framework of the alginate shells via electrostatic interaction between amino groups of APTES and carboxyl groups of alginate and the hybrid shells have a dense and homogeneous structure. In the formation reaction, the shrinking of the capsule shells occurs and the accumulation of APTES in the capsule shells proceeds with pseudo first-order kinetics. Moreover, these behaviors are greatly influenced by pH of the reaction solution, especially promoted under acidic and alkaline conditions.
authors.affiliation: Center for Optical Research & Education, Utsunomiya University, Yoto 7-1-2, Utsunomiya 321-8585, Japan. fkurayama@cc.utsunomiya-u.ac.jp
authors.forename: Fumio
authors.initials: F
authors.lastname: Kurayama
authors.forename: Satoru
authors.initials: S
authors.lastname: Suzuki
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Oyamada
authors.forename: Takeshi
authors.initials: T
authors.lastname: Furusawa
authors.forename: Masahide
authors.initials: M
authors.lastname: Sato
authors.forename: Noboru
authors.initials: N
authors.lastname: Suzuki
mesh_terms: D000464:Alginates / Q000138:chemical synthesis / Q000737:chemistry*; D002214:Capsules / Q000138:chemical synthesis* / Q000737:chemistry; D020723:Glucuronic Acid / Q000138:chemical synthesis / Q000737:chemistry; D006603:Hexuronic Acids / Q000138:chemical synthesis / Q000737:chemistry; D044367:Phase Transition; D011437:Propylamines; D012821:Silanes / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000464:Alginates; D002214:Capsules; D006603:Hexuronic Acids; D011437:Propylamines; D012821:Silanes; D020723:Glucuronic Acid; C477625:amino-propyl-triethoxysilane