Surface-initiated polymerization from TiO_2 nanoparticle surfaces through a biomimetic initiator: A new route toward polymer-matrix nanocomposites

摘要

Polymer nanocomposites of core-shell structure were prepared by grafting poly(methyl methacrylate) (PMMA) from TiO_2 nanoparticle via the surface-initiated polymerization (SIP) strategy. A bifunctional polymerization initiator inspired by L-3,4-dihydroxyphenyl-alanine (DOPA), a key constituent of mussel adhesive proteins (MAPs), was designed and synthesized for use in SIP from oxide surfaces. The biomimetic initiator spontaneously adsorbed to TiO_2 from aqueous solution, resulting in a colloidal initiator system with the initiator content of approximately 6.8 wt percent. Subsequent in situ activation of the surface-initiated atom transfer radical polymerization (SI-ATRP) gave rise to PMMA polymer shell layers tethered to TiO_2 nanoparticle cores. The results demonstrate a viable biomimetic strategy toward the preparation of polymer functionalized metal oxide nanoparticles that may be useful for construction of functional polymer nanocomposites.