Physically Controlled Radical Polymerization of Vaporized Vinyl Monomers on Surfaces. Synthesis of Block Copolymers of Methyl Methacrylate and Styrene with a Conventional Free Radical Initiator

Abstract

Physically controlled radical polymerization of vinyl monomers with conventional free radical initiators was achieved in the presence of monomer vapors on solid substrate surfaces. The polymerization of methyl methacrylate (MMA) and styrene (St) by 2,2‘-azobis(isobutyronitrile) (AIBN) on substrate surfaces resulted in the deposition of high molecular weight polymers, forming a rough surface morphology in such forms of aggregated particles. The proportional relationship between the number-average molecular weight and polymer yield was successfully obtained, and the consecutive copolymerization of MMA and St produced a block copolymer, poly(MMA-b-St). These results support the living nature of the free radical polymerization on surfaces in the presence of monomer vapors. The SEM observations of the deposits revealed that the polymerization proceeded with a continuous polymer deposition taking place at points where the active species were immobilized, reflecting a predesigned pattern on the substrate surface.

Surface Grafting of Polymers onto Nanoparticles in a Solvent-Free Dry-System and Applications of Polymer-grafted Nanoparticles as Novel Functional Hybrid Materials

“…Endo and coworkers reported physically controlled radical polymerization of vapor-phase vinyl monomers by conventional free-radical initiators deposited onto solid surfaces, such as aluminum plate. [76][77][78][79] Deposition polymerization in monomer vapor of MMA and styrene was initiated from free radicals on the surface and high molecular weight polymers formed on the substrate surfaces. During polymerization, the number-average molecular weight was found to increase linearly with polymer yield.…”

Hydrophobic cellulose fiber surfaces modified with 2,2,3,3,3-pentafluoropropylmethacrylate (FMA) by vapor-phase-assisted photopolymerization

“…This suggests that the propagation reaction was greatly accelerated once the reaction time exceeded 5 h. A similar phenomenon was observed in a previous study of VASP. 10 Thus, this acceleration must be caused by factors such as an increase in the adsorption and absorption area of monomer molecules and the suppression of termination reactions caused by the isolation of active chain ends on the top surface of deposits, as reported previously. 11 Multimodal profiles with wide polydispersity values are typical profiles of the photo-VASP products obtained in this study.…”

“…14 The molecular weight of the extracted polymers ranged from 28 600 to 1 160 000 in M w , with large polydispersity values of 2.6-4.9, consistent with the peculiar structural property of photo-VASP products as previously reported. 10,12,15 As listed in Table 1, PFMA production with HMPP gradually increased from 2.7 to 7.5 mg over a period of up to 5 h. Over 5 h, a significant increase in polymer accumulation (410.8 mg) was observed as shown in samples 1-5 (reaction time 6 h), with an extreme increase in molecular weight. This suggests that the propagation reaction was greatly accelerated once the reaction time exceeded 5 h. A similar phenomenon was observed in a previous study of VASP.…”

“…5-9 Previously, we reported physically controlled living radical polymerization using free radical initiators by the VASP method, enabling the preparation of block copolymers, 10 the design of fine patterns, application to surface coatings with a fluorinated polymer 11 and the development of a homogeneous coating of a fine Fe-powder surface. 12 In these studies, a small amount of organic solvent was used to precoat initiators on substrate surfaces.…”

Melt-Processable Nanocomposites Grafting-From Platelet Surfaces by Vapor-Assisted Surface Polymerization

“…It was also revealed that, because of a particular interaction between silicate platelet surfaces and MMA units in copolymer chains, a small number of MMA units in a styrene-MMA copolymer induced the exfoliation of layered silicates [30]. Considering the easy preparation of block copolymers and other advantageous features of VASP method [31], various designs of polymer structure by VASP could be created on the silicate layer surfaces to prepare nanocomposites that maintain their structures after melt processing.…”