Carbon Dots Synergizing with Phosphate Starch to Construct Dual Conduction Pathways for High-Performance Smart Packaging Films

作者：Xiaoxu Zhang, Chengguo Liu, Xiaoqin Yang, Qian Jiang, Can Liu, Ping Zhao, Jingyan Liu · 发表于：Materials · 年份：2025 · DOI：10.3390/ma18245644 · 被引用次数：3 · 研究领域：Carbon and Quantum Dots Applications、Electrochemical sensors and biosensors、Nanocomposite Films for Food Packaging

The advancement of smart packaging technology demands high-performance and sustainable sensing materials. While starch is a biodegradable natural polymer, its inherent high crystallinity restricts charge transport capability. This study developed a novel smart sensing film by incorporating ellagic acid-derived blue, fluorescent carbon dots (CDs) into phosphate starch (PS), which is rich in phosphorus. The effects of silver ions (Ag+), sodium carboxymethyl cellulose (CMC), and CDs on the film properties were systematically investigated. Results indicate that CDs act as flexible nano-crosslinkers, forming hydrogen bonds with PS molecular chains and effectively balancing strength and toughness—achieving a tensile strength of 5.1 MPa and an elongation at break of 24.1%. Phosphorus, in synergy with CDs, facilitates an efficient dual conduction pathway for ions and electrons: phosphate groups enable ion transport, while the conjugated carbon cores of the CDs provide electron transport channels. This synergistic effect significantly reduces the film’s electrical impedance from 6.93 × 106 Ω to 1.12 × 106 Ω (a reduction of 84%) and enhances thermal stability, increasing the char residue from 1.1% to 18.3%. The PS/CDs composite film exhibits a strong linear current response to pH in the range of 2–7 (R2 = 0.9450), and shows enhanced discrimination between fresh orange juice (pH = 3.38) and spoiled orange juice (pH = 2.68), with a current change of 0.62 × 10−5 A. Moreover, the film exhi...