Omniphobic coatings, which repel both water and oil, are important for applications that require fingerprint resistance, friction reduction, or frequent cleaning. To exhibit omniphobicity, coatings typically contain some combination of fluorination and surface roughness. However, monomers that constitute many commercial (semi)fluorinated polymeric coatings break down into perfluorooctanoates (PFOAs), biopersistent and toxic chemicals. This work looks at developing omniphobic polymer coatings from greener (less toxic) monomers than typical C8F17 PFOA derivatives. A primary design goal is to preserve repellency relative to commercial analogues while minimizing fluorine content. To this end, we synthesized a library of linear triblock terpolymers with fluorine-containing end blocks by sequential living anionic polymerization. Each triblock terpolymer was characterized in terms of fluorine content (NMR), nanoscale self-assembly (SAXS, TEM, and AFM), surface roughness (AFM), and surface repellency (contact angle goniometry) and compared to copolymer analogues from literature. The actual repellency was tuned by manipulating surface morphology in thin films via chemically modifying substrates and solvent annealing. Together, these data demonstrated that surface nanostructure is critical toward repellency in the design of greener omniphobic coatings.

Nanoscale self-assembly and morphology-dependent repellency of omniphobic triblock terpolymers

248th National Meeting (2014)

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