Construction of catechol-containing semi-fluorinated asymmetric polymer brush via successive RAFT polymerization and ATRP

A fluorine-containing anti-fouling surface was developed at a molecular-length scale by using a compositional heterogeneous polymer brush, which involves hydrophilic poly(ethylene glycol) (PEG) brushes with non-fouling functionality, fouling-release hydrophobic poly(2,2,3,3,3-pentafluoropropyl acrylate) (PPFA) brushes and catechol moieties, an important component of mussel adhesive proteins (MAPs), to anchor asymmetric polymer brushes onto surfaces. A well-defined PtBBPMA-co-PPEGMEMA-co-PDOMA macroinitiator was firstly prepared by RAFT copolymerization of tert-butyl 2-((2-bromopropanoyloxy) methyl) acrylate (tBBPMA) consisting of a Br-containing ATRP initiating group, poly (ethylene glycol) methyl ether methacrylate (PEGMEMA) macromonomer and N-(3,4-dihydroxyphenethyl) methacrylamide (DOMA) bearing an adhesive anchoring group of the catechol moiety. ATRP of PFA was then directly initiated by PtBBPMA-co-PPEGMEMA-co-PDOMA to afford (PtBA-co-PPEGMEMA-co-PDOMA)-g-PPFA asymmetric polymer brush via the grafting-from strategy. The asymmetric polymer brush surface could form a layer of amphiphilic brushes on the substrate with the assistance of adhesive anchoring groups through the drop coating technology. With dense heterogeneous brush conformation at a molecular-length scale, (PtBA-co-PPEGMEMA-co-PDOMA)-g-PPFA-based surface shows considerable anti-fouling performance with less protein adsorption (81.9% off) and cell adhesion (83.6% off) in comparison with bare surface.