Green Deep Eutectic Solvents for Functionalizing Chitosan-Dialdehyde Materials with Varied Crosslinker Content

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Chitosan is a promising biopolymer for advanced packaging but requires property modification.
• Previous modifications focused on single approaches like covalent crosslinking or plasticization.
• Synergistic effects of dual modification strategies remain largely unexplored.

Purpose of the Study:

• To develop novel chitosan-based films with enhanced structural, mechanical, and surface properties for advanced packaging.
• To investigate the synergistic effects of combining covalent crosslinking with dialdehyde starch (DAS) and plasticization with a deep eutectic solvent (DES).
• To systematically evaluate the impact of this dual modification on film characteristics.

Main Methods:

• Synthesized dialdehyde starch (DAS) via periodate oxidation of potato starch.
• Prepared chitosan films using solution casting, incorporating varying molar ratios of DAS and a choline chloride-malonic acid deep eutectic solvent (DES).
• Characterized films for molecular structure, density, mechanical properties, morphology, color, wettability, and surface free energy.

Main Results:

• Dual modification significantly reduced Young's modulus (1150 MPa to 130 MPa) and increased elongation at break (10% to ~90%).
• Surface free energy nearly doubled (32.5 to 59.9 mJ m^-2) upon incorporation of DAS and DES.
• Demonstrated synergistic improvements in mechanical and surface properties unattainable by single modification methods.

Conclusions:

• The dual modification strategy effectively engineers chitosan films for advanced packaging applications.
• Combining DAS crosslinking and DES plasticization offers synergistic benefits over individual treatments.
• This pioneering approach provides a new pathway for developing high-performance chitosan-based biomaterials.