Washable and Breathable Electret Sensors Based on a Hydro-Charging Technique for Smart Textiles

Abstract

Flexible electromechanical sensors based on electret materials have shown great application potential in wearable electronics. However, achieving great breathability yet maintaining good washability is still a challenge for traditional electret sensors. Herein, we report a washable and breathable electret sensor based on a hydro-charging technique, namely, hydro-charged electret sensor (HCES). The melt-blown polypropylene (MBPP) electret fabric can be charged while washing with water. The surface potential of MBPP electret fabric can be improved by optimizing the type of water, water pressure, water temperature, drying temperature, drying time, ambient air pressure, and ambient relative humidity. It is proposed that the single fiber has charges of different polarities on the upper and lower surfaces due to contact electrification with water, thereby forming electric dipoles between fibers, which can lead to better surface potential stability than the traditional corona-charging method. The HCES can achieve a high air permeability of ∼215 mm/s and sensitivity up to ∼0.21 V/Pa, with output voltage remaining stable after over 36,000 working cycles and multiple times of water washing. As a demonstration example, the HCES is integrated into a chest strap to monitor human respiration conditions.

Flexible, Breathable, and Hydrophobic Iontronic Tactile Sensors Based on a Nonwoven Fabric Platform for Permeable and Waterproof Wearable Sensing Applications

“…In detail, due to the excellent porous network structure, the fabric electrode has the highest permeability of 1161 mm s –1 ; after compositing with IL, the permeability of the fabric electrolyte decreases to 455.3 mm s –1 , and when assembled, the fabric sensor device shows a permeability of 224.9 mm s –1 , which is still much higher than that of nylon (∼79.1 mm s –1 ) and TPU film (∼34.2 mm s –1 ). Furthermore, Table S2 compares the air permeability between the fabric sensor developed in this work and those reported in the literature, ,,− indicating that the excellent permeability is achieved in the field. It is also found that the permeability of the sensor is positively influenced by the applied air pressure (Figure b).…”

Flexible coaxial composite fiber based on carbon nanotube and thermochromic particles for multifunctional sensor and wearable electronics

“…At the same time, in order to test the washability of the fibrous multifunctional sensor, we conducted a performance test on the sensor after several washes. 59–62 The pictures before and after cleaning and the performance test results are shown in Fig. S5 †.…”

Electrostatic Smart Textiles for Braille‐To‐Speech Translation

“…[35] Therefore, a Braille-to-speech translation system comprising of all-textile tactile sensors and loudspeakers with high performances and a facial fabrication process is in high demand. Textile integrated electrostatic transducers (ETs), based on the electrostatic induction effect, have been developed to serve as tactile sensors, [36][37][38] energy harvesters, [39][40][41] flexible microphones, [42] and soft actuators [43][44][45] due to their flexibility, lightweight, excellent output performance, and comfortability. For instance, a textile ET fabricated with conductive yarn and nylon yarn can achieve high-pressure sensitivity of 7.84 mV Pa −1 and excellent machine washability.…”