Flexible PDMS/La$_{0.7}$Sr$_{0.3}$MnO$_3$/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 PDMS/La0.7Sr0.3MnO3 (LSMO)/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 successful incorporation of PDMS, LSMO, and MWCNT components. The composite exhibits a smooth and uniform surface morphology, along with significantly enhanced thermal stability, retaining ~70% mass at elevated temperatures. Electrical measurements reveal thermally activated resistivity behavior, enabling temperature sensing functionality. Additionally, the composite shows a notable decrease in resistance under an applied magnetic field, exhibiting magnetoresistance due to spin-dependent transport in the LSMO phase. Mechanical testing indicates elastomeric behavior with a maximum load of ~0.49 N and stretchability of ~26%, along with ductile deformation characteristics. The multifunctional sensing properties arise from the synergistic interaction between the conductive MWCNT network and 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.