Polymer brushes have been shown as an alternative, non-toxic coating to reduce fouling, but typically require multiple surface modification steps and are impractical for large-scale deposition processes. Bottlebrush polymers present a potential alternative that can be synthesized in a batch reactor and subsequently deposited on a surface, resulting in a uniform brushy coating. However, scalable methods for depositing and crosslinking bottlebrush films have not been reported. In this study, we demonstrate that polystyrene (PS) bottlebrush polymers can be deposited from solution and crosslinked <i>on-demand </i>through UV irradiation. We show that short irradiation time is sufficient to produce crosslinked bottlebrush films that are solvent resistant by quantifying the residual film thickness after development. This crosslinking behavior was not observed with linear PS polymers. The effects of film thickness, curing time, light intensity, side chain length and composition on the extent of crosslinking are studied. We propose that the mechanism for crosslinking is thiol-ene coupling of the thiol terminated side-chains to double bonds of the backbone, and show that a bottlebrush without backbone double bonds does not crosslink under UV irradiation. We further show that addition of small molecular reagents for thiol-ene reaction increases residual film thickness. This approach is easily extended to different side-chain chemistries, including poly(ethylene oxide) (PEO) and poly(lactic acid) (PLA). This work demonstrates a rapid and straightforward process to deposit and crosslink bottlebrush thin films.

Rapid processing of bottlebrush coatings through UV-induced crosslinking

256th National Meeting (2018)

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