Self-healing polyurethane elastomer/amphiphilic nanocellulose composites with capability of antibacterial property

Nanofillers usually suppress the self-healing capability of the matrix, because they restrict polymer-chain mobility. This study aims to develop polyurethane nanocomposites with integrated self-healing and antimicrobial properties by simultaneously introducing non-covalent interactions. Initially, chemical modification was used to introduce quaternary ammonium and amphiphilic ionic groups onto cellulose nanofibers, producing amphiphilic nanocellulose (Am-CNF). Subsequently, Am-CNF was mixed with a self-healing ionic polyurethane (IPU) in different proportions using a solution-mixing method to create a series of self-healing antimicrobial APUs. The results indicate that the incorporation of Am-CNF didn’t deteriorate the self-healing behavior and endowed the composites with attractive antibacterial properties through electrostatic interactions with bacteria. At room temperature, the self-healing of the composites is even faster than that of pure IPU, as observed by optical microscopy and 3D confocal microscopy. The developed APUs demonstrated rapid self-healing capabilities and showed up to 99.9% antimicrobial efficacy against both Gram-positive and Gram-negative bacteria. Cellular and animal tests further validated the biosafety of these samples and indicated their potential as medical or packaging materials.