Reactive Polyvinylamine-Graft-TEMPO/Laccase Complex Giving Wet Cellulose Adhesion

Abstract

Cellulose surfaces are activated for wet adhesion, bioconjugation and other applications by the introduction of a “primer” layer consisting of a covalently bonded polyelectrolyte complex based on laccase and polyvinylamine with pendent TEMPO groups, PVAm-T . The laccase, in conjunction with dissolved oxygen, activates the TEMPO moieties on PVAm-T, facilitating the oxidation of primary hydroxyl groups on the cellulose surface. The resulting cellulosic aldehydes are free to couple covalently with amine groups on the PVAm-T . The generally accepted mechanism of TEMPO oxidation is that the primary oxidant converts TEMPO into a reactive oxoammonium ion that shuttles an electron to primary alcohols. Since the translational mobility of TEMPO will be limited when grafted to a polymer and present as a polyelectrolyte complex with laccase, it is proposed that the activated oxoammonium ions jump along the PVAm-T chain, from TEMPO to neighbouring TEMPO. Wet adhesion of laminated regenerated cellulose sheets was used as the primary assay indicating the presence of covalent bonding.