Affiliation:
1. International Institute for Nanocomposites Manufacturing (IINM) WMG University of Warwick Coventry CV4 7AL UK
2. School of Engineering Newcastle University Newcastle upon Tyne NE1 7RU UK
3. DeFENS Department of Food Environmental and Nutritional Science Packaging Division University of Milan Via Celoria 2 Milan 20133 Italy
4. Warwick Medical School University of Warwick Coventry CV4 7AL UK
5. Faculty of Sciences Holon Institute of Technology – HIT Holon 58102 Israel
6. Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovot 76100 Israel
Abstract
AbstractThe inclusion of tungsten disulphide nanotubes (WS2 NTs) in chitosan, plasticized with glycerol, facilitates the formation of a polyelectrolyte complex. The glycerol interrupts the intramolecular hydrogen bonding between chitosan chains allowing positively charged protonated amines of chitosan to form a complex with negatively charged oxygen ions chemisorbed to the tungsten atoms in defects. These interactions, with the unique mechanical and chemical properties of WS2 NTs, result in a chitosan film with superior properties relative to unfilled chitosan. Even at low WS2 NT loadings (≤1 wt%), the Young's modulus (E) increases by 59%, tensile strength (σ) by 40% and tensile toughness by 74%, compared to neat chitosan, without sacrificing ductility. Addition of highly dispersed WS2 NTs significantly improves the gas barrier properties of chitosan, with a 50% reduction in oxygen permeability, while the addition of both glycerol and WS2 NTs to chitosan effectively reduces the carbon dioxide permeability by 80% and the water vapor transmission rate by 90%. The intrinsic antimicrobial efficacy of chitosan against both Gram‐positive and Gram‐negative bacteria is enhanced on inclusion of WS2 NTs. Polyelectrolyte complexation of WS2 NTs and glycerol‐plasticized chitosan provides a cost‐effective, sustainable route to biodegradable films with desirable mechanical, gas barrier properties, and antimicrobial efficacy suitable for food packaging applications.
Funder
Weizmann Institute of Science
Subject
Mechanical Engineering,Mechanics of Materials