Multi-scale hybrid In situ tow scale carbon fiber reinforced thermoplastic strain sensor

Abstract In this study, strain self-sensing of carbon fiber reinforced thermoplastic (CFRTP) composite was investigated using the electrical resistance. The self-sensing researches limited to the thermoset composites motivated the study for the investigations with CFRTP. Additional treatment was performed during the manufacturing to enhance its electromechanical sensitivity and mechanical properties by subtracting carbon fiber tows, in situ interfacial polymerization, and adding graphene oxide (GO) to the polymer. Isolating the sensing tow increased the electromechanical sensitivity because the reduced electrical network was more sensitive to the mechanical deformation. In-plane electrical network to the nearby tows was restricted by eliminating the adjacent carbon fiber tows from the sensing tow. Through-thickness network was controlled by the in situ interfacial polymerization of the sensing tow with polyamide 6,6 (PA 6,6). GO was added to the polymer to enhance the mechanical properties. These additional treatments were converted into equivalent electrical circuit modeling to comprehend the electromechanical behavior of the CFRTPs. The electromechanical sensitivities of the developed CFRTPs increased by 270% compared with control sample. The novel advantages of the proposed method are low cost, easy implementation, in situ integrated smart sensors, and tunable customized electromechanical sensitivity.