Plasticizing of chitosan films with deep eutectic mixture of malonic acid and choline chloride. (1st October 2018) - Sokolova, Maria P.
Graphical abstract: Highlights: A novel chitosan films containing up to 82% of deep eutectic solvent were prepared. A strong interaction of chitosan with a deep eutectic solvent (DES) was observed. The plasticizing effect of DES on the chitosan was demonstrated. Fast and complete dissolution of chitosan/DES films in pure water was found. The nanoscale mechanical properties of chitosan films were probed for the first time. Abstract: Chitosan (CS) films containing deep eutectic solvent (DES) based on malonic acid (MA) and choline chloride (ChCl) were successfully prepared by solution casting method by using DES content ranging from 0 to 82 wt%. A strong interaction of CS with the components of DES was demonstrated by analyses of water sorption isotherms, atomic force microscopy and FTIR results. The plasticizing effect of the MA and ChCl mixture on the CS matrix was shown by static bulk mechanical measurements, thermal analysis and quantitative nanomechanical mapping (QNM). Elongation at break increased from 3 to 62% at increase of DES content from 0 to 67 wt%, while further increase of DES content led to the decreasing of maximal elongation. Introduction of DES into CS films led to the appearance of glass transition temperature in the region +2 - -2.3 °C. QNM results indicated homogeneity of the films containing up to 75 wt% of DES.