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

Abstract

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.