The adhesion of marine organisms on surfaces such as ship hulls, and fishing nets causes higher fuel consumption and maintenance costs. To overcome these problems, cationic polymers containing a quaternary ammonium moiety can be used to prevent settlement. A challenge with linear polymers is that their flexible structures lead to different morphologies when wet versus dry, likely changing their anti-fouling ability. Bottlebrush polymers with dense branches off the polymer backbone are less flexible and can help stabilize the structure. In this work, cationic macromonomer homopolymerization, which has not been reported in literature, was demonstrated to create bottlebrush polymers via ring opening metathesis polymerization (ROMP). Using these methods, amphiphilic bottlebrush block copolymers of cationic polymers and polystyrene (PS) were created. Prior to ROMP, the tertiary amine macromonomers of poly(dimethylamino ethyl acrylate) (PDMAEA) were made via reversible addition-fragmentation chain transfer (RAFT) polymerization to generate polymers with a polymerizable norbornene end group (macromonomer). The PDMAEA macromonomers were quaternized with hexyl halide and dodecyl halide to obtain quaternary ammonium macromonomers with different quaternary ammonium substituents (PDMAEA-Ca-X macromonomer, where a is the number of carbons in alkyl group and X is the halide counter ion). PDMAEA-C6-Br was successfully polymerized by ROMP to cationic bottlebrush polymers with targeted molecular weights and low dispersity by controlling the ratio of macromonomer (MM) to catalyst. PDMAEA-C6-I also underwent ROMP, but at a slower rate due to ligand exchange between the catalyst and macromonomer halides. Amphiphilic bottlebrush block copolymerization was accomplished by polymerizing PS MMs as the first block and PDMAEA-C6-Br MMs as the second block. Block copolymers with a variety of block compositions were synthesized with desired molecular weights and low dispersity.

Synthesis of bottlebrush polymers with quaternary ammonium macromonomers for anti-marine fouling

2019 Fall National Meeting

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