Halochromic polybutylene adipate terephthalate (PBAT) for acid base sensor

A novel pH sensory material of biodegradable halochromic film based on polybutylene co-adipate tereph-thalate (PBAT) that can change color at acidic and base exposure is presented. The effect of starch and polyethylene glycol (PEG) addition on the efficacy of halochromic pH films was assessed. The solution casting method was used to fabricate the halochromic film, and the incorporation of PBAT, starch, PEG, and dye was confirmed using Fourier transform infrared (FTIR). The halochromic film sensitivity to color changes was revealed by Ultraviolet-Visible Spectroscopy (UV-Vis), and the mechanical performance was determined by tensile strength, elongation at break and young's modulus. The halochromic film dis-plays a clear color response from yellow in an acidic solution to purple in the base solution. The transition from yellow to purple color can be clearly seen at pH 6, between 420 and 450 nm and 550-600 nm absor-bance peak. The addition of starch enabled the halochromic properties, and PEG improved the homogene-ity of dye spreading onto the film. On top of that, PEG increased the flexibility of the PBAT-pH sensor, suggesting a wide potential for use in many applications such as food packaging as well as biomedical and environmental industrial applications. Real testing of food applications using lemon and fish were investigated where the film revealed a clear color change on 2nd day of exposure to fish, indicating that the halochromic film was efficient to sense pH changes due to bacterial activities in fish decomposition. However, the color changes under the acidic condition were less relevant.Copyright (c) 2022 Elsevier Ltd. All rights reserved.Selection and peer-review under responsibility of the 14th AUN/SEED-Net Regional Conference on Mate-rials and 4th International Postgraduate Conference on Materials, Minerals and Polymer (RCM & MAMIP 2021).

Automated summary

A biodegradable halochromic film based on PBAT was developed as a novel pH sensory material that can undergo color changes in acidic and base exposure. The addition of starch and PEG improved the efficacy of the pH film. The film was fabricated through solution casting method and its characteristics were evaluated using FTIR, UV-Vis spectroscopy, and mechanical tests. The results showed that the film exhibited clear color response and mechanical performance. Real testing on food applications demonstrated its potential in sensing pH changes due to bacterial activities. The film has wide applications in food packaging, biomedical, and environmental industries.