Continuous Flow Fabrication of Block Copolymer–Grafted Silica Micro‐Particles in Environmentally Friendly Water/Ethanol Media

Abstract

Polymer‐grafted inorganic particles (PGIPs) are attractive building blocks for numerous chemical and material applications. Surface‐initiated controlled radical polymerization (SI‐CRP) is the most feasible method to fabricate PGIPs. However, a conventional in‐batch reaction still suffers from several disadvantages, including time‐consuming purification processes, low grafting efficiency, and possible gelation problems. Herein, a facile method is demonstrated to synthesize block copolymer–grafted inorganic particles, that is, poly(poly(ethylene glycol) methyl ether methacrylate) (PPEGMEMA)‐b‐poly(N‐isopropylacrylamide) (PNIPAM)–grafted silica micro‐particles using continuous flow chemistry in an environmentally friendly aqueous media. Immobilizing the chain transfer agent and subsequent SI‐CRP can be accomplished sequentially in a continuous flow system, avoiding multi‐step purification processes in between. The chain length (MW) of the grafted polymers is tunable by adjusting the flow time or monomer concentration, and the narrower molar mass dispersity (Ð < 1.4) of the grafted polymers reveals the uniform polymer chains on the particles. Moreover, compared with the in‐batch reaction at the same condition, the continuous system also suppresses possible gelation problems.

Tailoring the mechanical properties of polymer nanocomposites via interfacial engineering

“…Various strategies have been suggested for the control of the spatial distribution of NPs, invoking their surface modification such as by adding surfactants (cationic, anionic or nonionic), [24][25][26] inorganic surface modification, 27,28 adsorbent modification, 29,30 and using grafted polymer chains. 29,31 The last method is rather popular, [32][33][34] and in this case, the grafted chains are similar to an amphiphilic material, promoting the compatibility of NPs with the polymer matrix. In this case, the interfacial interactions can be tuned by controlling the grafting density, the grafted chain length, the polymer matrix chain length and the diameter of NPs.…”

PET‐RAFT polymerization under flow chemistry and surface‐initiated reactions

“…SI‐CRP has been performed from various particles (e.g. silica, 82 iron oxide, 83 and graphene oxide 84 ) and different planar substrates, including silicon wafers, 85 gold, 86 and indium tin oxide (ITO) 87 . Advincula and colleagues 88 combined electrochemistry and SI‐RAFT polymerization to prepare cell‐resistant poly(polyethylene glycol methyl ether methacrylate) brushes on conducting gold surfaces.…”

Harnessing autocatalytic reactions in polymerization and depolymerization

“…A number of advances have been made in having a desirable control over kinetics of polymerization by using a continuous flow during polymerization. Examples include control over molecular weight (MW) and its distribution in free-radical polymerization, living free-radical polymerization by reversible addition fragmentation chain transfer (RAFT) in ethanol and water [51] as well as diblock copolymerization on grafted polymers [52] (cf. Fig.…”