Preparation and characterization of biodegradable cellulose nanofiber films modified with methylene blue and vitamin C for detecting oxidants.

In this study, cellulose nanofiber film was modified with methylene blue (MB) dye and vitamin C (Cel/MB/VC). The physicochemical and antibacterial characteristics of the prepared films were investigated. The rate of absorption and release of MB from the prepared film was studied. Films containing MB and VC were used as a kit to detect hydrogen peroxide. The results showed that MB and VC increased the thickness of the film and the elongation of the film. Both MB and VC agents reduced moisture and water vapor permeability, which significantly increased the antioxidant and antimicrobial properties (against Escherichia coli and Staphylococcus aureus) of the film. SEM images showed that the diameter of cellulose fibers is between 20 and 100 nm, which MB and VC completely cover their surface and the surface porosity of the film. FTIR spectra confirmed the electrostatic interactions between cellulose, MB and VC. According to the XRD results, cellulose has a crystalline structure, which is improved further on the vitamin C is added. According to TGA, MB and VC promoted thermal stability of the cellulose films. The release of methylene blue from the film was reported to be 15%. In the presence of HO, the color of the films containing MB and VC changed from white to blue, and that showed good performance as a hydrogen peroxide detection sensor (kit). The highest sensitivity of the sensor for measuring HO was 0.299 (100 mg/ml) with a detection limit of 1.9 (100 mg/ml).