Preparation of flexible pressure sensors for intelligent sensing terminals and interdisciplinary comprehensive experimental teaching design

Rapid advances in intelligent wearables, mobile healthcare, and integrated energy systems have increased demand for flexible, highly sensitive, and environmentally friendly sensing terminals. Traditional pressure sensors, often based on metals or semiconductors, face significant limitations, including poor flexibility, limited sensitivity, complex fabrication, and recycling challenges, which hinder their use in next-generation intelligent systems. Concurrently, cultivating interdisciplinary talent with integrated innovation and practical engineering skills is urgent. However, current sensor-related experimental courses often lack comprehensive training that spans material synthesis, device fabrication, system integration, and application. This study aims to address these dual challenges by developing a high-performance, eco-friendly flexible pressure sensor and transforming the corresponding research outcomes into a structured interdisciplinary experimental teaching project, thereby bridging the gap between advanced research and engineering education.

A sandwich-structured flexible pressure sensor was designed and fabricated using reduced graphene oxide (rGO-impregnated fabric as the active sensing layer and laser-induced graphene (LIG) as the porous top and bottom electrodes. The rGO fabric was prepared via a simple soaking–thermal reduction process, in which a piece of cotton-linen blend fabric was immersed in a graphene oxide dispersion and subsequently thermally reduced at 200℃. The LIG electrodes were directly patterned onto polyimide (PI) films using a CO2 laser engraving system, creating a three-dimensional porous conductive network. The sensor was assembled by sandwiching the r GO fabric between two LIG/PI electrodes. The morphology and composition of the rGO fabric and LIG were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy, and Raman spectroscopy. The sensor's electromechanical performance, including sensitivity and stability, was systematically evaluated using a universal testing machine coupled with a digital source meter. The sensor's practical application potential was demonstrated by detecting static forces with standard weights and by monitoring dynamic physiological signals to capture human radial artery pulse waveforms.

The fabricated sensor exhibited excellent overall performance. The rGO formed a continuous conductive coating on the fabric fibers, while the LIG exhibited a highly porous and interconnected structure, enabling efficient signal transduction. The sensor demonstrated a high sensitivity of 30.3 kPa^-1 in the low-pressure range (0–5 kPa). It showed outstanding stability, with negligible performance degradation over 300 loading-unloading cycles at 5 kPa. The sensor could clearly distinguish static loads and reliably capture dynamic physiological signals. The pulse waveform displayed characteristic peaks, from which a heart rate of approximately 72 beats per minute was derived, consistent with the resting state of a healthy adult. This interdisciplinary experiment, integrating knowledge from electrical engineering, materials science, and biomedical engineering, was successfully implemented as a teaching module. It guided students through the complete research cycle, from design and fabrication to testing and application analysis. The teaching practice achieved important outcomes, including supporting student teams in obtaining National-level University Student Innovation Training Program projects and winning a provincial silver medal in the China International College Students' Innovation Competition.

This work successfully developed an eco-friendly, low-cost, high-performance flexible pressure sensor based on rGO fabric and LIG porous electrodes. More importantly, it established an effective model for translating cutting-edge research into a comprehensive interdisciplinary experimental teaching project. This project addresses the shortcomings of traditional sensor experiments by offering students hands-on experience throughout the device development workflow. It effectively enhances students' interdisciplinary integration capabilities, practical engineering skills, and innovative thinking, thereby offering a reproducible and scalable educational paradigm for cultivating interdisciplinary talent under the emerging engineering education initiative.