Generating morphologically and chemically diverse surfaces through post-polymerization modification of polymer brushes

Click chemistry combined with post-polymerization modification (PPM) of reactive polymer brushes can result in a wide array of surfaces, differing in chemical functionalities and morphologies.1 Poly(pentafluorophenyl acrylate) (Poly(PFPA)) brushes react quickly and quantitatively towards primary amines, with few side reactions, and have been shown to be a promising reactive scaffold for use in templating a variety of functionalities and morphologies to make diverse surface coatings.2 Here, morphologically and  chemically diverse substrates are fabricated from poly(PFPA) surfaces with excellent control over surface properties. Morphology is controlled through the fabrication of nanoscale surface creases using two different methods of PPM with Jeffamine M-2070, an amine functionalized copolymer of poly(ethylene glycol) and poly(propylene glycol).3,4 Through isolation and manipulation of reaction variables, the factors driving crease formation in reactive polymer brush scaffolds are studied in order to further apply this phenomenon to other systems. Chemically diverse surfaces are also generated through the fabrication of a tri-functional surface. Using reactive microcapillary printing, poly(PFPA) brushes can be partially patterned with other click functionalities, such as strained cyclooctyne derivatives and sulfonyl fluorides.5 This tri-reactive surface can then react selectively with high fidelity in a one pot reaction via three orthogonal chemistries at room temperature: activated ester aminolysis, strain promoted azide–alkyne cycloaddition, and sulfur(VI) fluoride exchange, all of which are tolerant of ambient moisture and oxygen.6 This approach allows for the development of highly complex surface motifs patterned with different chemistries and morphologies.

1Iha, R. K; Wooley, K. L.; Nystrom, A. M.; Burke, D. J.; Kade, M. J.; Hawker, C. J. Chem. Rev. 2009, 109, 5620-5686.

2Arnold, R. M.; Sheppard, G. R.; Locklin, J. Macromolecules 2012, 45, 5444-5450.

3Brooks, K.; Razavi, M. J.; Wang, X.; Locklin, J. ACS Nano 2015, 9, 10961-10969.

4Brooks, K.; Razavi, M. J.; White, E. M.; Wang, X.; Locklin, J. Adv. Mater. Interfaces 2017, Accepted.

5Brooks, K.; Yatvin, J.; McNitt, C. D.; Reese, A. R.; Jung, C.; Popik, V. V.; Locklin, J. Langmuir 2016, 32, 6600-6605.

6Yatvin, J.; Brooks, K.; Locklin, J. Chem. Eur. J. 2016, 22, 16348-16354.