Antioxidant and Adsorption Properties of Bioinspired Phenolic Polymers: A Comparative Study of Catechol and Gallol

Polyphenols, which by the Quideau definition are plant-derived chemicals with two or more phenolic groups, have attracted interest because of their antioxidant activity, adsorption on universal substrates, and biocompatibility. Most polyphenols include gallol groups in their chemical structures, which has inspired us to synthesize gallol-functionalized polymers. We report the reversible addition-fragmentation chain transfer polymerization of 3,4,5-trimethoxystyrene using cyanomethyl dodecyl trithiocarbonate as the chain transfer ag(e)nt. This method produces well-defined polymers with a wide range of molecular weight (from 5.4 to 53.4 kg mol(-1)) and low polydispersity index (M-w/M-n < 1.3). Subsequent demethylation of poly(3,4,5-trimethoxystyrene) (PTMS) yields poly(3,4,5-trihydroxystyrene) (polyvinylgallol, PVGal). These newly synthesized polymers exhibit greater antioxidant activities than widely used catechol-functionalized polymers based on the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and oxygen radical absorbance capacity (ORAC) methods. Also, PVGal showed better adsorption properties on metals and SiO2 substrates than those of the other phenolic polymers. Given these high antioxidant and adsorption properties, the effective use of gallol-funcationalized polymers in biomaterials is expected.