Effect of molecular weight on the properties of chitosan films prepared using electrostatic spraying technique

• Published in: Carbohydrate polymers Vol. 212; pp. 197 - 205
• Main Authors: Zhong, Yu, Zhuang, Chenjun, Gu, Weiqi, Zhao, Yanyun
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.05.2019
• Subjects: Chitosan; Electrostatic spraying; Film property; Molecular weight; Chitosan; Electrostatic spraying; Film property; Molecular weight
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2019.02.048

[Display omitted] •Chitosan (CH) could form stand-alone film by electrostatic spraying (ES) technique.•Molecular weight (MW) of CH impacted solution property and then film quality.•CH solution was well atomization while spray cone angle was reduced with MW.•With increased MW, structure of CH film was more compact and crystallographic.•Water barrier ability and tensile strength of film were improved along with MW. Chitosan (CH) films were prepared with different number-average molecular weight (MW, ca. 6.55, 12.93 and 47.70 kDa) and concentration (0.5, 0.75, and 1.0%) using electrostatic spraying (ES) technique. The effects of MW on film-forming solution properties, ES-atomization performances, and film characteristics were investigated. With increase of MW, conductivity, viscosity, surface tension, and contact angle of CH film-forming solution was raised due to the increases of proportions of amine-groups and degrees of CH chain entanglements. Spray cone angle was generally higher at 12.93 kDa, while the average median diameters of film-forming solution droplets were in the range of 6.3–12.0 μm, indicating well atomization effect. Water barrier property and tensile strength of CH films were improved along with increased MW, which was in accordance with the more completed, rougher and more crystalline microstructures implying by SEM, AFM and XRD. However, film antibacterial capacities against E.coli and L. innocua were descended with increased MW. Considering the overall properties, CH film prepared by 47.70 kDa at 0.5% possessed the best performances.