Surface-initiated ring-opening metathesis polymerization of pentadecafluorooctyl-5-norbornene-2-carboxylate from variable substrates modified with sticky biomimic initiator

A novel strategy is reported to produce low surface energy poly(pentadecafluorooctyl-5-norbornene-2-carboxylate) brushes (PNCA-F ₁₅) on surfaces of variable metals and metallic oxides. PNCA-F ₁₅ brushes are grafted from biomimic catecholic initiator via surface-initiated ring-opening metathesis polymerization at ambient conditions. The biomimic catecholic initiator can assemble on a variety of substrates, such as Ti(TiO₂), Al(Al₂O₃), steel, Au, Cu, Ag, and Zn, and on both nanoparticles and planar substrates, allowing successful grafting of low surface energy polymer brushes from these substrates. The polymer brush modified substances were characterized by thermogravimetric analysis, X-ray photoelectron spectroscopy, water contact angle measurements, and atomic force microscopy. The PNCA-F₁₅ brushes grow progressly with time with highly uniform surface coverage. Very uniform polymer layer with the thickness 11 nm is obtained after 2 h polymerization at 0.25 M monomer concentration. Thermogravimetric analysis shows the grafting amount of PNCA-F₁₅ is 39.3% (2 h). Upon grafting on rough surfaces, e.g., electrochemically anodized alumina and titania, superhydrophobicity and superoleophobicity in particular can be achieved; e.g., the PNCA-F₁₅ grafted rough TiO₂ nanotubes films exhibit static water contact angle of 170°.