The continuous development of controlled living polymerization technique and polymer chemistry, including ATRP, RAFT, ring-opening polymerization, and click chemistry, provide more opportunities in the synthesis of unique and complex polymer architectures. Well-defined architecture gives controlled physical properties for tailored applications. Up to today, many complex polymers including comb polymer, star polymer, brush polymer, dendrimers have been made. Based on previous studies, the highest polymer-chain grafting density on the particle is around 1 chain/nm<sup>2</sup>. In this study, a series of soft and high grafting density polymeric nanoparticles are synthesized and characterized. Polymeric core with grafted polymer chains contribute to the super soft property. The grafting density is estimated to be 10 times higher than regular hairy nanoparticles. The structure and morphology of soft polymeric nanoparticles is well controlled by monomer starved semi-batch nano-emulsion polymerizations, rate of monomer addition and crosslinking density. The synthesis method produces 5-20 nm radii polystyrene nanoparticles with tunable morphologies. Poly (4-methyl styrene) nanoparticles was successfully brominated (62%) to produce functionalized soft nanoparticles (poly(benzyl bromide) soft nanoparticles). The benzyl bromide group functions as the initiator for atom-transfer radical polymerization (ATRP). A series of polymers including poly butyl methacrylate (PBMA), poly hexyl methacrylate (PHMA) were grafted via surface initiated-ATRP. The impact of polymer grafting to the soft nanoparticles on their physical properties were carefully studied. Furthermore, the application of the hairy soft nanoparticles in bulky polymer as a lubricant was also investigated.

Synthesis and characterization of soft and high grafting density nanoparticle

2019 Fall National Meeting

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