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Assemblies of Polyacrylonitrile-Derived Photoactive Polymers as Blue and Green Light Photo-Cocatalysts for Cu-Catalyzed ATRP in Water and Organic Solvents.

ABSTRACT: Photoluminescent nanosized quasi-spherical polymeric assemblies prepared by the hydrothermal reaction of polyacrylonitrile (PAN), ht-PLP_PAN, were demonstrated to have the ability to photo-induce atom transfer radical polymerization (ATRP) catalyzed by low, parts per million concentrations of Cu^II complex with tris(2-pyridylmethyl)amine (TPMA). Such photo induced ATRP reactions of acrylate and methacrylate monomers were performed in water or organic solvents, using ht-PLP_PAN as the photo-cocatalyst under blue or green light irradiation. Mechanistic studies indicate that ht-PLP_PAN helps to sustain the polymerization by facilitating the activation of alkyl bromide species by two modes: 1) green or blue light-driven photoreduction of the Cu^II catalyst to the activating Cu^I form, and 2) direct activation of dormant alkyl bromide species which occurs only under blue light. The photoreduction of the Cu^II complex by ht-PLP_PAN was confirmed by linear sweep voltammetry performed under illumination. Analysis of the polymerization kinetics in aqueous media indicated even though Cu^I complexes comprised only 1-1.4% of all Cu species at equilibrium, they exhibited high activation rate constant and activated the alkyl bromide initiators five to six orders of magnitude faster than ht-PLP_PAN.

SUBMITTER: Sun M

PROVIDER: S-EPMC8407075 | biostudies-literature |

REPOSITORIES: biostudies-literature

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