Dendritic fibrous nanosilica loaded chitosan for improving water vapor permeability and antibacterial properties of waterborne polyurethane acrylate membranes

ABSTRACT Functional membranes with both water vapor permeability (WVP) and antibacterial properties are not only important in scientific research but are also increasingly required by leather applications. However, creating polymer membranes with both of these properties is still a significant challenge. In this work, dendritic fibrous nanosilica (DFNS) loaded with chitosan (CS) nanoparticles was mixed with waterborne polyurethane acrylate (WPUA) to prepare DFNS@CS/WPUA membranes via in-situ polymerization. Due to the high surface area, V-shaped pore structure, large pore volume and guest molecule accessibility of DFNS, the chitosan was well-encapsulated and showed good dispersibility. As a result, the WPUA/DFNS@CS hybrid membrane not only exhibited a clear increase in WVP, from 121.8 g/m2·24 h to 278.8 g/m2·24 h, but also showed outstanding antimicrobial activity against Escherichia coli, Staphylococcus aureus and Aspergillus niger. In addition, the stress of the membrane increased from 27.3 MPa to 35.9 MPa and its water resistance also improved. This study demonstrates a new method for preparing multifunctional membranes with potential applications in wearable fabrics and leather coating.