Fabrication of in situ polymerized polyaniline‐based functional nanofibrous structures for flexible electromechanical devices

Abstract

Abstract Recently, flexible electromechanical devices (EMDs) emerged as alternatives to rigid electronics, promoting polymeric materials over traditional semiconductors. This study develops EMDs using conductive nanofibrous membranes of thermoplastic polyurethane (TPU), polyaniline (PANI), and multi‐walled carbon nanotubes (MWCNTs) in various structures. The fabrication technique included the combination of electrospinning and in situ polymerization to create random and aligned conductive membranes. Morphological, mechanical, thermomechanical, and electrical characterizations were conducted to assess their potential in EMDs applications. Mechanical testing revealed that, in comparison to aligned pure TPU mats, aligned TPU/PANI and TPU/MWCNTs/PANI membranes exhibited maximum strains of 26% and 19%, respectively. Meanwhile, randomly oriented mats, TPU/PANI and TPU/MWCNTs/PANI demonstrated maximum strains of 18% and 27%, respectively. Moreover, incorporating PANI and/or MWCNTs increased the Young's modulus. Thermogravimetric analysis showed thermal stability up to 250°C for all mats, with TPU/PANI mats demonstrating superior stability. Dynamic mechanical analysis revealed that PANI incorporation increased the storage modulus from 119 and 180 MPa to 2012 and 1367 MPa for aligned and random mats, respectively, compared with pure TPU mats. The combination of MWCNTs and PANI yielded moduli of 1501 and 1096 MPa, respectively. All conductive mats exhibited symmetric ohmic behavior, with conductivities varying based on orientation and composition. Specifically, TPU/PANI and TPU/MWCNTs/PANI mats exhibited conductivities of 0.83 and 1.78 S/cm for aligned mats, and 0.35 and 0.67 S/cm for random mats, respectively. Pure TPU, on the other hand, displayed a conductivity of 1.8 × 10 −10 S/cm, indicating a significantly lower conductivity compared with the other mats.