Multiblock copolymers composed of polymer segments of sufficiently high molecular weight such that microphase separation and self-assembly can occur provide a pathway to a myriad of nano-engineered materials. We have focused on synthesis of multiblock copolymer nanoparticles in environmentally friendly aqueous emulsion polymerization based on reversible addition-fragmentation chain transfer (RAFT) polymerization using the three most commonly industrially employed monomer families in emulsion polymerization, namely methacrylates, acrylates and styrene. Due to the submicron-size of the polymeric nanoparticles that form the locus of polymerization, the polymerization can proceed at a significantly higher rate than the corresponding homogeneous (solution, bulk) system. Exploitation of such compartmentalization effects enables access to polymer structures that are challenging to prepare under homogeneous polymerization conditions, especially using slowly propagating monomers such as methacrylates.<br/>The concept of nano-engineering of polymer nanoparticle morphology is demonstrated by exploiting the ability to covalently link numerous polymer blocks that are chemically incompatible, resulting in microphase separation and formation of a well-defined multilayered structure within the nanoparticles (Fig. 1). The method developed is environmentally friendly (use of water as solvent) and fulfils all requirements for scale up to an industrial process using existing industrial equipment; no intermediate purification steps, relatively high solids content, good colloidal stability with no flocculation/coagulation as well as near full monomer conversion in each sequential polymerization step.

Multiblock copolymer synthesis and nanoparticle engineering in environmentally friendly aqueous-based emulsion systems

2019 Fall National Meeting

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