Estudo das propriedades ópticas e eletrônicas de materiais compósitos poliméricos: uma abordagem de integração aos dispositivos inteligentes de identificação

Abstract

In this study, the physical, electronic, and optical properties of synthesized polymeric materials were investigated and applied to the substrates of an RFID device capable of communicating with a mobile application. The conductive polymer polyaniline (PAni-ES) was synthesized and characterized using X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). A pure sample of PAni-ES was analyzed for its electrical conductivity, reaching 15.8 S/cm, and peaking at 81.6 S/cm when graphite was added in incremental portions. Another composite, composed of polyvinyl alcohol (PVOH) and PAni-ES with highly pure micrometric graphite, exhibited an ohmic resistance of 58 Ω/cm². Due to its lower elasticity, this composite was applied as a film in the touch interface circuit. Furthermore, a blend of multi-walled carbon nanotubes (MWCNT), epoxy resin, and PAni-ES was used in an RFID antenna, achieving 140 Ω/cm². For transparency control, a polymer-dispersed liquid crystal (PDLC) film was energized by the control circuit, reaching up to 80% transparency in the transition from opaque to transparent. Activation of the PDLC revealed a recoverable pattern. The mechanism is controlled by the command circuit, with power modulated by battery-powered substrates. The RFID device communicates passively with the mobile device via Near Field Communication (NFC). The mobile application securely recognizes the unique identifier (UID) of the tag, activates the substrate, and allows the code to be recovered via the camera. This integrated approach enhances authentication levels through the use of the explored polymeric materials.