Antimicrobial Cellulose Nanocrystals Containing Quaternary Ammonium Polymers Prepared via Atom Transfer Radical Polymerization

Abstract

Nanomaterials have been widely used as antimicrobial agents for their high efficiency. However, the lack of recovery techniques and toxicity has raised concerns for the use of these materials. Cellulose nanocrystals (CNCs), extracted from plants and agriculture biomass via acid hydrolysis possess many unique features, such as high mechanical strength, high aspect ratio, excellent colloidal stability, and biocompatibility. With the growing interests in green chemistry and chemical process, the modification and utilization of CNCs has appealed to more scientists and researchers. In this study, a CNCs based antimicrobial nanomaterials was developed by grafting poly(diethylaminoethyl methacrylate) (PDMAEMA) via surface-initiated ARGET-ATRP and quaternizing the grafted polymer. The grafting density and molecular weight of the PDMAEMA-g-CNC was controlled by adjusting the surface initiator immobilization and monomer concentration. The degree of quaternization of different PDMAEMA-g-CNCs with various grafting density and chain length were evaluated, and the antimicrobial activity was tested. It is found that the types of quaternizing agents, grafting density, and polymer chain length could affect the surface charge, morphology, degree of quaternization, and antimicrobial activity of CNCs. The smaller quaternizing agents, lower chain density and longer chain length could lead to higher degree of quaternization and enhance the antimicrobial activity of the Q(PDMAEMA)-g-CNC. These findings could be applied to optimize the CNC ATRP surface grafting systems and could be potentially used in applications, such as Pickering emulsion, antimicrobial and drug delivery.