Origami-Inspired Conductive Paper-Based Folded Pressure Sensor with Interconnection Scaling at the Crease for Novel Wearable Applications.

Drawing inspiration from origami structures, a pressure sensor was developed with unique interconnection scaling at its creases crafted on a conductive paper substrate, paving the way for advanced wearable technology. Two screen-printed conductive paper substrates were combined face-to-face, and specific folds were introduced to optimize the sensor structure. The Electrical Contact Resistance (ECR) was systematically analyzed across different fold numbers and crease gaps, revealing a notable trade-off: while increasing the number of folds expanded the sensing area, it also influenced the ECR, reaching a performance plateau. Strategic modifications in the sensor's design, including refining interconnections at the crease, enhanced its sensitivity and stability, culminating in a remarkable sensitivity of 3.75 kPa-1 at subtle pressure levels (0-0.05 kPa). This sensor's real-world applications proved to be transformative, from detecting bruxism and aiding in neck posture correction to remotely sensing trigger finger locking phenomena, highlighting its potential as a pivotal tool in upcoming medical diagnostics and treatments.

Skin-Inspired Tactile Sensor on Cellulose Fiber Substrates with Interfacial Microstructure for Health Monitoring and Guitar Posture Feedback.

Skin-inspired flexible tactile sensors, with interfacial microstructure, are developed on cellulose fiber substrates for subtle pressure applications. Our device is made of two cellulose fiber substrates with conductive microscale structures, which emulate the randomly distributed spinosum in between the dermis and epidermis layers of the human skin. The microstructures not only permit a higher stress concentration at the tips but also generate electrical contact points and change contact resistance between the top and bottom substrates when the pressure is applied. Meanwhile, cellulose fibers possessing viscoelastic and biocompatible properties are utilized as substrates to mimic the dermis and epidermis layers of the skin. The electrical contact resistances (ECR) are then measured to quantify the tactile information. The microstructures and the substrate properties are studied to enhance the sensors' sensitivity. A very high sensitivity (14.4 kPa-1) and fast recovery time (approx. 2.5 ms) are achieved in the subtle pressure range (approx. 0-0.05 kPa). The device can detect subtle pressures from the human body due to breathing patterns and voice activity showing its potential for healthcare. Further, the guitar strumming and chord progression of the players with different skill levels are assessed to monitor the muscle strain during guitar playing, showing its potential for posture feedback in playing guitar or another musical instrument.