Electrospun PEO/PEDOT:PSS Nanofibers for Wearable Physiological Flex Sensors

Abstract

Flexible sensors are fundamental devices for human body monitoring. The mechanical strain and physiological parameters coupled sensing have attracted increasing interest in this field. However, integration of different sensors in one platform usually involves complex fabrication process-flows. Simplification, even if essential, remains a challenge. Here, we investigate a piezoresistive and electrochemical active electrospun nanofibers (NFs) mat as the sensitive element of the wearable physiological flex sensing platform. The use of one material sensitive to the two kinds of stimuli reduces the process-flow to two steps. We demonstrate that the final NFs pH-Flex Sensor can be used to monitor the deformation of a human body joint as well as the pH of the skin. A unique approach has been selected for pH sensing, based on Electrochemical Impedance Spectroscopy (EIS). A linear dependence of the both the double layer capacitance and charge transfer re-sistance with the pH value was obtained by EIS, as well as a linear trend of the electrical resistance with the bending deformation. Gauge factors values calculated after the bending test were 45.84 in traction and 208.55 in compression mode, reflecting the extraordinary piezoresistive behavior of our nanostructured NFs.

Electrospun Nanofibers for Optimized Fiber-Shaped Wearable Sensors

“…The following values were selected: 1.5, 2.2, 2.5, 3.5, and 5 wt%, with respect to PEO. As largely implemented in our works [5,6,9], all prepared polymeric solutions were loaded into a syringe and electrospinning process was provided (NANON 01A by MECC). In this work, two rotating collectors were used, both made of PE: one was an insulating wire and the second one a hollow wire.…”

“…Several works in the literature have proposed sensors characterized by good sensitivity, and, at the same time, many limitations have been raised, mainly that they are addicted to low flexibility and mechanical properties; therefore, there is a necessity to develop sensitive nanostructured materials that are capable of overcoming all the described limitations [3]. To satisfy all features, we propose electrospun nanofibers as sensitive elements, since they, thanks to their intrinsic properties, allow the design of flexible sensors with increased electrical and mechanical performances [4][5][6]. We proposed composite polyethylene oxide/multiwall carbon nanotube (PEO/MWCNTs) nanofibers as the sensitive materials [2].…”

Study on the decay behavior of a flexible sensor based on silver fiber fabrics

“…In general, selecting highly sensitive materials as the basic structure of sensors is a common strategy to improve sensitivity. Research on sensing materials currently involves liquid metals [5] , conductive polymers [6] , and conductive fabrics [7] . Textiles have drawn a lot of interest in creating flexible electronic devices because of their many benefits, including high comfort, outstanding breathability, exceptional flexibility, and lightweight design.…”

Development of High-Sensitivity Piezoresistive Sensors Based on Highly Breathable Spacer Fabric with TPU/PPy/PDA Coating

“…Commonly used conductive materials include metal particles, carbon-based materials, and conductive polymers, of which, conductive polymers are good candidates for piezoresistive pressure sensors due to their excellent conductivity and good biocompatibility. Commonly used conductive polymers include polypyrrole (PPy) [ 30 , 31 , 32 ], polythiophene [ 33 ], polyaniline [ 34 ], etc. Among these, polypyrrole (PPy) is a good candidate for the preparation of sensors due to its simple synthesis process, low cost, high oxidation resistance, high conductivity and specific capacitance values, and easy film formation [ 35 , 36 ].…”