A flexible and stretchable photonic crystal film with sensitive structural color-changing properties for spoiled milk detection

• Published in: Food Chemistry: X Vol. 16; p. 100526
• Main Authors: Thao, Do Thi Vien, Weng, Wei-Tzu, Hieu, Nguyen Van, Chang, Cheng-Chung, Wang, Gou-Jen
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 30.12.2022; Elsevier
• Subjects: Flexible and stretchable photonic crystals; Nanimprinting; Spoiled milk detection; Strain-controllable structural color change; Flexible and stretchable photonic crystals; Nanimprinting; Spoiled milk detection; Strain-controllable structural color change
• ISSN: 2590-1575; 2590-1575
• DOI: 10.1016/j.fochx.2022.100526

[Display omitted] •We propose a smart flexible and stretchable polymer film with photonic crystals for visible detection of spoilage milk.•This film enables the simultaneous change of photonic crystal periodicity and incident angles with minimal strain.•The structural color change of the fabricated SCPC TPU film can be easily achieved by a small stretch force.•Food spoilage can be easily detected by the structural color change caused by the gas it produces.•The proposed structural color change detection method will not cause any chemical contamination of the targeting food. This study proposes a flexible and stretchable 3D polymer film with photonic crystals for the visible detection of spoiled milk. Thermoplastic polyurethane (TPU) was used as the substrate for the photonic crystal structure. The back barrier layer with a regular array of nanohemispheres of anodic aluminum oxide film was used as a template for electroforming a nickel mold. The nanohemisphere array was then nanoimprinted onto the TPU substrate to form a strain-controllable photonic crystal (SCPC) structure on it. Food spoilage can be easily detected by the structural color change caused by the gas it produces. Experimental results confirmed that the structural color change of the fabricated SCPC TPU film occurred when the elongation (ΔL) of the film reached 0.2 mm (1.2 %). Furthermore, spoiled milk detection experiments showed that the proposed SCPC TPU film is a highly intelligent and cost-effective biosensor for detecting spoiled food in a container.