Flexible PDMS/La0.7Sr0.3MnO3/MWCNT Composite Thin Films for Multifunctional Temperature and Magnetic Sensing Electronic Skin

Abstract

The development of multifunctional electronic skin (e-skin) requires materials that combine mechanical flexibility with responsiveness to multiple stimuli. In this work, a flexible polydimethylsiloxane (PDMS)/La0.7Sr0.3MnO3 (LSMO)/multiwall carbon nanotube (MWCNT) composite thin film was fabricated via solution casting, using LSMO powder synthesized by a solid-state reaction method. Structural and spectroscopic analyses confirm the formation of single-phase rhombohedral LSMO and the successful incorporation of PDMS, LSMO, and MWCNT components. The composite exhibits a smooth and uniform surface morphology, along with significantly improved thermal stability, retaining 70% of its mass at elevated temperatures. Temperature-dependent electrical measurements showed semiconducting behavior with an ∼17% change in resistivity over a temperature variation of ∼100 °C, enabling temperature sensing functionality. Furthermore, the composite exhibited pronounced negative magnetoresistance of approximately 27% under an applied magnetic field, arising from spin-polarized transport in the LSMO phase. Mechanical characterization revealed a tensile strength of ∼0.49 MPa, stretchability of ∼26%, and ductile deformation behavior, while nanoDMA measurements indicated a dominant elastic response with low viscoelastic loss. The multifunctional sensing properties arise from the synergistic interaction between the conductive MWCNT network and the magnetically active LSMO within the flexible PDMS matrix. Overall, the composite demonstrates a unique combination of thermal stability, mechanical flexibility, and dual sensing capability, making it a promising material for next-generation e-skin applications.