Location: Dairy and Functional Foods
Title: Choline chloride based ionic liquid analogues as tool for the fabrication of agar films with improved mechanical properties Authors
Submitted to: Carbohydrate Polymers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 7, 2014
Publication Date: April 19, 2014
Citation: Sousa, A.M., Souza, H.S., Latona, N.P., Liu, C., Goncalves, M.P., Liu, L.S. 2014. Choline chloride based ionic liquid analogues as tool for the fabrication of agar films with improved mechanical properties. Carbohydrate Polymers. DOI: 10.1016/j.carbpol.2014.04.019. Interpretive Summary: Seaweed is an abundant natural resource that could be used for biofuel applications if costs are reduced. One way to reduce biofuel costs would be to expand applications for seaweed by-products in a biorefinery. Agar, obtained from red seaweed, is commonly used in solid biological culture media and as a gelling agent thickener in foods. Although agar derived gels and films have been reported in analytical chemistry, wound healing and transdermal drug delivery, they are brittle and swell quickly following contact with water, which limits applications. In the present study, agar was dissolved in a novel ionic liquid containing the essential nutrient choline, where agar films were cast. The resultant agar films have strong mechanical properties and improved water resistance. This research expands the utilities of seaweed polymers, which would reduce the cost of biofuel production in a biorefinery.
Technical Abstract: In the present paper, we test the suitability of Choline-Cl/urea (DES-U) and Choline-Cl/glycerol (DES-G) eutectic mixtures at 1:2 molar ratios for the production of agar biodegradable films. A three-step process is proposed: pre-solubilization of polymer in DES followed by compression-molding and subsequent drying. The mechanical properties, water resistance and microstructure of the films were evaluated at different polymer concentrations. DES-U showed by far the best film forming ability. Agreeing with the diffusion and SEM data, the best films were found at the lowest and highest agar concentrations (tensile strengths of 24.2-42 MPa and elongations of15.4-38.9%). The water absorption and contact angle studies suggested increased hydrophilicity for the lower agar concentration film. The use of choline-derived ionic liquids as solvent and plasticizer might be a promising tool for the development of new non-aqueous biomaterials based on seaweed polysaccharides.