Multifunctional Integration in Carbon Nanotube-Engineered Thermoplastic Vulcanizate (TPV) Nanocomposites: From High-Performance Elastomer to Smart Flexible Strain Sensor with High Sensitivity and Durability

The current demand for thermoplastic vulcanizates (TPVs) in industry has shifted from singular fundamental properties toward the integration of multifunctional and intelligent applications. Developing high-performance TPVs tailored for specialized fields and incorporating carbon nanotubes (CNTs) to achieve synergistic enhancements in multifunctional performance hold significant importance. Herein, we developed smart CNT/TPV nanocomposites based on hydrogenated acrylonitrile butadiene rubber (HNBR) and thermoplastic polyester elastomer (TPEE), integrating heat and oil resistance with strain-sensing functionality. By modulating the distribution and interconnectivity of CNTs, conductive networks were constructed. Morphological studies reveal that increasing CNTs content leads to their interconnection within TPEE and at HNBR/TPEE interfaces. A high CNT content facilitates a densely interconnected strain-responsive network, forming a unique shell-bridge hybrid conductive pathway for efficient electron transport. Consequently, the CNT/TPV sample exhibits a high dielectric constant (214 at 100 Hz), low dielectric loss (1.74), and high conductivity, with a percolation threshold of 7.02 wt %. Increased CNT content also enhances the rubber/CNTs dual network, improving modulus, hardness, and oil resistance. The flexible sensor fabricated from CNTs/TPV composites demonstrates high sensitivity (gauge factor = 148.4), a wide detection range (0%–103%), and superior durability (maintains stable electrical signal response after over 104 tensile cycles). Moreover, this sensor accurately detects varying strains and motion states, enabling real-time movement monitoring with rapid response capabilities (250 ms).