Comparative Electromagnetic Shielding Performance of Ti₃C₂Tₓ–PVA Composites in Various Structural Forms: Compact Films, Hydrogels, and Aerogels

Abstract

The structural design of lightweight MXene-polymer composites has attracted significant interest for enhancing both electromagnetic interference (EMI) shielding performance and mechanical strength, which are critical for practical applications. However, a systematic understanding of how various structural configurations of MXene composites affect EMI shielding is lacking. In this study, lightweight Ti3C2Tx -PVA composites were fabricated in three structural forms hydrogel, aerogel, and compact film while varying the Ti3C2Tx areal density (14 to 20 mg cm⁻²) to elucidate the role of structural design in X-band EMI shielding and mechanical properties. EMI shielding performance depends on the structural configuration and areal density of MXene in Ti3C2Tx-PVA composites. The shielding effectiveness increases with the increasing Ti3C2Tx content in each configuration. At a fixed Ti3C2Tx areal density of 0.02 g cm⁻², the Ti3C2Tx -PVA hydrogel demonstrated the highest shielding effectiveness (SE = 70 dB at 10 GHz), attributed to strong dipole polarization and efficient ionic conduction behavior, followed by the compact film (40 dB) and then the aerogel (21 dB). Notably, the aerogel achieved the highest absorption coefficient (A=0.89) due to the improved impedance matching and pronounced internal reflections, whereas the hydrogels and compact films exhibited reflection-dominated shielding. Furthermore, the incorporation of PVA polymer molecules into Ti3C2Tx MXenes significantly enhanced their mechanical properties across all configurations: the hydrogel achieved high stretchability (636%), the aerogel displayed superior compressive strength (0.215 MPa), and the compact film reached a tensile strength of 56 MPa, each surpassing the performance of its pristine Ti3C2Tx MXene counterpart. Overall, tailoring the structural configuration into a hydrogel, aerogel, or compact film offers versatile routes for optimizing both EMI attenuation and mechanical performance of MXene polymer composites.