Three-dimensional conductive networks constructed from Ag-decorated MWCNTs in biodegradable polymer composites for high-performance strain sensing.

Abstract

Traditional conductive films such as indium tin oxide (ITO) suffer from the environmental issue of being difficult to degrade and recycle, whereas biodegradable poly(butylene succinate) (PBS) is limited by its intrinsically poor electrical conductivity, making it unsuitable for direct application in flexible electronic devices. To address this challenge, this study constructed Ag-aMWCNTs/TSPANI/PBS ternary composite conductive films with a three-dimensional conductive network through mixed acid modification, silver ion decoration, and in situ solution polymerization, and systematically investigated their structure, properties, and sensing applications. The results indicate that the composite system is a physical blend, and the introduction of Ag-aMWCNTs does not alter the crystal structure of PBS. However, the formed conductive network effectively restricts molecular chain movement and acts as a nucleating agent, significantly enhancing the thermal stability and crystallization performance of the composites. When the Ag-aMWCNT content is 3%, the conductive film exhibits the best overall balance of electrical conductivity, mechanical properties, and degradation performance. The charge transfer resistance is as low as 1.183 × 106 Ω, with degradation rates of 25.84% and 26.37% in soil and enzymatic environments, respectively. The conductive films show sensitive and stable periodic current responses to respiration, swallowing, joint bending, and cyclic pressing, demonstrating promising application prospects in the field of degradable flexible sensing.