Bottlebrush polymers are highly branched macromolecules with polymeric side-chains. The novel structure of bottlebrush polymers may make them particularly useful in specialty applications, and here we explore the surface and solution properties of model thermoresponsive poly(N-isopropylacrilamide) (PNIPAAM) bottlebrush polymers. The resulting PNIPAAM bottlebrush polymers are fully soluble in water only after removal of the terminal chain transfer agent, reflecting a disproportionately strong effect of the side-chain end groups on bottlebrush polymer solubility (Figure 1 (a)). Above the LCST, PNIPAAM bottlebrush polymers aggregate, and PNIPAAM bottlebrush polymers with 9 kg/mol side-chains form a lyotropic liquid crystal phase, evidenced by low-angle scattering peaks and birefringence under polarized optical microscopy at temperatures above the LCST. Small-angle neutron scattering (SANS) measurements of PNIPAAM bottlebrush polymers in D2O demonstrate that the side-chains collapse as the temperature increases towards the lower critical solution temperature (LCST); both the LCST and the collapse of the side-chains is dependent on the side-chain length IFT measurements show that PNIPAAM reduces the interfacial tension to values comparable to linear PNIPAAM homopolymer. Antifouling studies by quartz-crystal microbalance show a reduction in cell attachment onto a gold surface with PNIPAAM coatings. This study demonstrates the potentially useful interfacial and surface properties of bottlebrush polymers. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/240nm/uploads/42621_melittin_jpg.jpg' alt='' />

Thermoresponsive bottlebrush polymers

247th National Meeting (2014)

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