Halochromic PLA/PEG as real‐time solution and vapor sensing

Abstract

In this study, halochromic sensor-based poly (lactic acid) (PLA) and polyethylene glycol (PEG) film as real-time sensing is successfully fabricated. Bromocresol purple (BCP) dye concentrations were varied (0.01 and 0.03 wt%/vol) in halochromic PLA/PEG film that changed its color from yellow to purple at a basic environment. The efficacy of the film with more BCP loading toward basic sensing was significant, where the material showed distinct color change with rapid response time. The color changes were proven by the CIE lab analysis, which showed that the initial and final colors of the indicator after interaction with PLA/PEG film are well above the limit for visual perception. The film response in base vapor was further determined by the amount of total volatile basic nitrogen (TVB-N) released from mackerel. The mackerel was kept at room temperature (26 ± 1 C) for 24 h and chiller temperature (3 ± 1 C) for 11 days. The threshold of food spoilage indicated by the TVB-N and the ΔE was reached at 18 h at room temperature when it started to deteriorate on Day 7 in the chiller. The findings suggest that a pH-sensor made of the PLA/PEG/BCP films is suitable for multiple applications, particularly in base solution and vapor sensing detection.