A versatile macro-initiator with dual functional anchoring groups for surface-initiated atom transfer radical polymerization on various substrates

A versatile macro-initiator with dual functional anchoring groups for surface-initiated atom transfer radical polymerization (SI-ATRP) on various substrates is reported. Conventional free radical copolymerization was performed with N-(3,4-dihydroxyphenyl) ethyl methacrylamide (a dopamine anchor-containing monomer), 4-(1-pyrenyl) butyl methacrylate (a pyrene anchor-containing monomer), and 2-(2-bromoisobutyryloxy) ethyl methacrylate (an ATRP-initiating monomer) to produce a random copolymer. Dopamine anchors on the copolymer could assemble on the macroscopic planar substrates (e.g., Si, Ti, Au, Cu, stainless steel, Al2O3, PI, PTFE, PDMS, textile, and wood) and pyrene anchors on the carbon-based nanoscaled materials (e.g., two-dimensional graphene oxide and one-dimensional carbon nanotubes). The successful preparation of polymer brushes through SI-ATRP in a water and methanol system from various substrates was characterized via ATR-IR, AFM, XPS, TGA, and TEM, which confirmed the versatility of the macro-initiator. More importantly, a synergistic anchoring effect between catechol and pyrene groups was discovered, leading to high quantities of grafted polymers from the graphene oxide substrates. Microcontact printing of the macro-initiator was also demonstrated in the formation of patterned surfaces on the Ti substrate.