Eletrodos flexíveis com compósitos de polianilina, nanotubos de carbono e lignina para sensores de pressão

Abstract

This work reports the development, characterization, and optimization of pressure sensors based on single-walled carbon nanotubes (SWCNTs) and polyaniline (PANI)/lignin blends. The devices were fabricated on flexible polyethylene terephthalate (PET) substrates using spin coating for SWCNT deposition and blade coating for the PANI/lignin films. The results demonstrate that the incorporation of lignin significantly modifies the electromechanical properties of the electrodes, enabling the tuning of sensor sensitivity while extending the operating pressure range. Pure PANI exhibits high initial sensitivity (≈0.47-0.60 MPa⁻¹), but its response saturates at approximately 2.1 MPa. In contrast, formulations containing 3 wt% and 10 wt% lignin show lower sensitivities (≈0.035 and ≈0.049 MPa⁻¹, respectively), while providing an extended sensing range of up to approximately 5-6 MPa. The devices exhibit response times below 1 s and excellent repeatability during cyclic tests. Therefore, the combination of SWCNTs, PANI, and lignin resulted in low-cost, flexible pressure sensors with a wide operating range and competitive performance compared with technologies reported in the literature, highlighting their potential for pressure monitoring and flexible electronics applications.