Photoinduced Miniemulsion Atom Transfer Radical Polymerization

Abstract

Photomediated atom transfer radical\npolymerization (photoATRP)\nof (meth)­acrylic monomers was conducted in miniemulsion media. The\npolymerization procedures took advantage of an ion-pair catalyst formed\nby interaction of Cu/TPMA² (TPMA = tris­(2-pyridylmethyl)­amine)\nand an anionic surfactant, sodium dodecyl sulfate (SDS). The ion-pair\ncatalyst was efficient in controlling ATRP reactions with catalyst\nloadings as low as 100 ppm. The effect of different polymerization\nparameters, such as the size of the reaction vial, amount of surfactant,\nand solids content influencing the photoATRP in miniemulsion, was\nstudied. The polymerization was conducted with solids content ranging\nfrom 5 to 50 vol % under a moderate surfactant loading (<5 wt %\nrelative to monomer). Excellent temporal control was achieved upon\nswitching the UV light on and off multiple times, and the polymer\nwas successfully chain extended, indicating high retention of chain-end\nfidelity.