Structural optimization and antibacterial property of alkylimidazole salt/carboxymethyl cellulose/starch composite films.

As a green solvent, alkylimidazolium salt has attracted much attention due to high antibacterial activity and excellent biocompatibility. In this work, 1-allyl-3-alkylimidazolium bromide ionic liquids (AIMB) were synthesized in a closed system. Using carboxymethyl cellulose (CMC) and starch (SR) as carriers, 1-allyl-3-dodecylimidazolium bromide ionic liquid (AIMC12)/CMC/SR (AIMCS) films were prepared via solution casting method. The AIMC12 exhibited the highest antibacterial activity. Under the optimized ratio of CMC to SR, the AIMCS-1-1 film showed effective antibacterial properties for E. coli and S. aureus with the inhibition zone of 3.50 cm and 3.02 cm, respectively. In addition, the tensile strength and elongation at break of AIMCS-1-1 reached to 4.5 MPa and 111.6 %, and its Young's modulus was 1.4 GPa. Therefore, as-prepared AIMB will be expected to replace traditional antibacterial agents in antibacterial applications, and as-prepared AIMCS films as the green packaging materials have potential application in antibacterial packaging.