Novel synthesis of poly(methyl methacrylate) brush encapsulated silica particles

Abstract

Silica (SiO 2 )-crosslinked polystyrene (PS) particles possessing photofunctional N,N-diethyldithiocarbamate (DC) groups on their surface were prepared by the free-radical emulsion copolymerization of a mixture of SiO 2 (diameter ¼ 20 nm), styrene, divinyl benzene, 4-vinylbenzyl N,N-diethyldithiocarbamate (VBDC), and 2-hydroxyethyl methacrylate with a radical initiator under UV irradiation. In this copolymerization, the inimer VBDC had the formation of a hyperbranched structure by a living radical mechanism. The particle sizes of such core-shell structures [number-average particle diameter (D n ) ¼ 35-40 nm] were controlled by the variation of the feed amounts of the monomers and surfactant, or emulsion system. The size distributions were relatively narrow (weight-average particle diameter/D n % 1.05). These particles had DC groups on their surface. Subsequently, poly(methyl methacrylate) brush encapsulated SiO 2 particles were synthesized by the grafting from a photoinduced atom transfer radical polymerization approach of methyl methacrylate initiated by SiO 2 -crosslinked PS particles as a macroinitiator.

Architecture of polymer particles composed of brush structure at surfaces and construction of colloidal crystals

“…In previous works [24][25][26], the reduction of DC groups at the peripheral sites of hyperbranched polymers and at the side chain ends of polymer brushes was recognized from the disappearance of methylene proton (d = 3.68 and 4.00 ppm) of DC groups by 1 H NMR spectra. The content of DC groups on the surfaces of the CSP particles was measured as follows.…”

“…Ishizu et al [25,26] reported that the architecture of polymeric superstructure films by locking the cubic lattices of cross-linked core-shell particles in a poly (methyl methacrylate) (PMMA) matrix was composed of three phase-separated microdomains.…”

Synthesis of tailored core–brush polymer particles via a living radical polymerization and architecture of colloidal crystals

“…In previous works [22,23], the reduction of DC groups at the peripheral sites of hyperbranched structures was recognized from the disappearance of methylene protons (d = 3.68 and 4.00 ppm) of DC groups by 1 H NMR spectra. The content of DC groups on the surface of the EP particles was measured as follows.…”

“…Subsequently, core-brush particles were synthesized by the photo-induced atom transfer radical polymerization (ATRP) of MMA initiated by photo-functional PS particles as a macroinitiator. Moreover, we have also applied this method for the synthesis of poly(methyl methacrylate) (PMMA) brush encapsulated silica particles [23]. More recently, hybrid materials have been also developed through the synthesis of colloidal silica surrounded by elastomer polymer brushes [24].…”

Synthesis of silica hybrid nanoparticles modified with photofunctional polymers and construction of colloidal crystals

“…Subsequently, core‐shell particles were synthesized by photo‐induced atom transfer radical polymerization (ATRP) of MMA initiated by photofunctional PS particles as a macroinitiator. Moreover, we have extended this idea to the synthesis of PMMA brushes encapsulated SiO 2 particle 21. That is, SiO 2 ‐crosslinked PS (possessing photofunctional DC groups on their surface) core‐shell particles were synthesized first by free‐radical emulsion copolymerization of a mixture of St, DVB, VBDC, and 2‐hydroxyethyl methacrylate (HEMA) with a radical initiator under UV irradiation.…”