Chitosan-functionalized silica nanoparticles as a multifunctional coating material for improved water repellency, antimicrobial activity and mechanical strength of degradable bioplastics

With the mounting plastic pollution fast becoming a global environmental catastrophe, there is a growing effort to develop and utilize plastics that can be biodegraded in a facile manner. One of the major challenges facing more widespread usage of these degradable bioplastics is the premature structural disintegration, especially at the surface, mainly due to their inherent mechanical weakness and continuous hydrolysis. To overcome these limitations, this study herein presents a simple, and yet highly effective strategy of coating the surface of bioplastics with chitosan-functionalized silica nanoparticles (SNP). SNP itself has been widely demonstrated to be an effective hydrophobic coating material, but introducing chitosan on SNP not only further increase the hydrophobicity, but also similarly enhance the mechanical strength of the bioplastics through increased physical interaction with cationic chitosan. Furthermore, the natural anti-microbial activity of chitosan could be imparted to the coated surface. As a whole, the chitosan-functionalized SNP is highly advantageous as a multifunctional coating material. Graphical abstract: [Figure not available: see fulltext.].