Investigation on the temperature dependence and mechanism of conductive behavior of conductive natural rubber composite with negative temperature coefficient

Abstract Conductive polymer composites (CPCs) often face complex service‐temperature problems. To systematically investigate the influence of temperature on the electrical conductivity and sensing behavior of CPCs, multiwalled carbon nanotube (MWCNT)/natural rubber (NR) composites were studied herein. The research results showed that within the temperature range of −20°C to 60°C, the MWCNT/NR composites had a negative temperature coefficient. Their conductive behavior strengthened with increasing temperature; thus, the composites showed good temperature cycling stability. Increasing temperature was beneficial for the improvement of the monotonicity and symmetry of the resistance–strain response of the composites and the shoulder peak phenomenon. Between 0°C and 60°C, their resistance was less affected by temperature changes and the internal‐charge conduction mechanism was ohmic conduction. Compared with applied voltage and generated strain, temperature more notably influenced charge transport in the composites. Through analytical testing and coarse‐grained molecular dynamics simulation, the systematic mechanism underlying the influence of temperature on the electrical conductivity and sensing behavior of the MWCNT/NR composites was revealed. Further, the influence of thermal expansion and thermal fluctuations on the electrical conductivity of the MWCNT/NR composites was discussed, indicating that thermal fluctuation plays a dominant role. Overall, this research lays a solid foundation for eliminating temperature interference in the sensing response of MWCNT/NR composites and optimizing their sensing response accuracy. Highlights Exploring the relationship between temperature and sensing behavior of MWCNT/NR. Revealing the influence mechanism of temperature on the sensing of MWCNT/NR. MWCNT/NR exhibits cyclic, stable sensing behavior with negative coefficient. Stable sensing response significant for temperature compensation.