Deep eutectic solvents as functional additives for Starch-based films

The interest in biofilms based on starch has grown in recent years, since it is an abundant biopolymer which forms resistant materials.³ Starch-based biofilms are generally produced by the solubilization of the biopolymer in a solvent containing a plasticizer additive. The film-forming solution undergoes a drying operation to form the desired material. ¹ As these films are brittle, the plasticizer addition is imperative to reduce the interactions between adjacent molecules and improve the film's flexibility.4 Therefore, the objective of this work was to study the effect of the addition of ionic liquid (IL) and deep eutectic solvents (DES) as plasticizing agents. Additives were synthesized as described in the literature.¹ The film characterization was performed on a UV-vis spectrophotometer (wavelengh 700 nm) and the thickness was measured on a digital micrometer. Both additives were used in the film formulation which were prepared by the casting method. The plasticizers amount is shown in the Table 1. For comparison, we prepared a film containing only 1% glycerol as plasticizer. The data presented in Table 1 show a decrease in film thickness when DES was used as plasticizer as opposed to the data obtained with IL when compared to the standard film of glycerol. It was also observed that the addition of DES contributed to an increase in film transparency. In this way, DES is a new alternative for the biofilms production.