Bottlebrush polymers are highly branched macromolecules capable of unprecedented control over biologically relevant factors: shape, size, and chemical functionality. Here, we show that bottlebrush polymer functionality and properties are tuned by varying the composition and molecular weight of the grafted side-chain polymers. We study the shape, solution properties, and biocompatibility of bottlebrush polymers with poly(ethylene glycol)(PEG), poly(lactic acid)(PLA), and fluorescently labeled poly(NIPAAm) side-chains. First we synthesized different side-chain polymers with a norbornene endgroup. The bottlebrush side-chains range in molecular weight from Mw 2 000 � 7 000 g mol-1while the overall molecular weight is 100 � 1 1000 kg mol-1. Bottlebrush polymers with amphiphillic PLA-block-PEG copolymer side-chains (Mw130 kg mol-1) display second order structure in SANS data after dialysis against water. The hydrophobic cores of amphiphillic bottlebrushes can encapsulate drug molecules and the core size is tunable by changing the molecular weight of PLA. The solubility and side-chain extension of mixed bottlebrush polymers, having both PLA and PEG homopolymer side-chains, are compared to copolymer bottlebrushes. Fluorescent bottlebrush polymers were synthesized by random co-polymerization of NIPAAm and fluorescein O-methacrylate (FMA) by RAFT. The resulting bottlebrush material was MW 420 kg mol-1 with side-chain Mw4300 g mol-1 and is water soluble. Bottlebrush polymers are characterized by H1NMR, GPC, DSC and SANS, and backbone DP is quantified by light scattering. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/240nm/uploads/45609_acs_abstract.jpg' alt='' />

Bottlebrush polymers: Custom shape, size, and composition of polymer nanoparticles

247th National Meeting (2014)

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