Strain and Pressure Sensors Based on MWCNT/PDMS for Human Motion/Perception Detection

Abstract

Flexible wearable devices have attracted wide attention in capacious fields because of their real-time and continuous monitoring of human information. The development of flexible sensors and corresponding integration with wearable devices is of great significance to build smart wearable devices. In this work, multi-walled carbon nanotube/polydimethylsiloxane-based (MWCNT/PDMS) resistive strain sensors and pressure sensors were developed to integrate a smart glove for human motion/perception detection. Firstly, MWCNT/PDMS conductive layers with excellent electrical and mechanical properties (resistivity of 2.897 KΩ · cm, elongation at break of 145%) were fabricated via a facile scraping-coating method. Then, a resistive strain sensor with a stable homogeneous structure was developed due to the similar physicochemical properties of the PDMS encapsulation layer and MWCNT/PDMS sensing layer. The resistance changes of the prepared strain sensor exhibited a great linear relationship with the strain. Moreover, it could output obvious repeatable dynamic response signals. It still had good cyclic stability and durability after 180° bending/restoring cycles and 40% stretching/releasing cycles. Secondly, MWCNT/PDMS layers with bioinspired spinous microstructures were formed by a simple sandpaper retransfer process and then assembled face-to-face into a resistive pressure sensor. The pressure sensor presented a linear relationship of relative resistance change and pressure in the range of 0–31.83 KPa with a sensitivity of 0.026 KPa−1, and a sensitivity of 2.769 × 10−4 KPa−1 over 32 KPa. Furthermore, it responded quickly and kept good cycle stability at 25.78 KPa dynamic loop over 2000 s. Finally, as parts of a wearable device, resistive strain sensors and a pressure sensor were then integrated into different areas of the glove. The cost-effective, multi-functional smart glove can recognize finger bending, gestures, and external mechanical stimuli, which holds great potential in the fields of medical healthcare, human-computer cooperation, and so on.

Antimicrobial Hydrogels: Potential Materials for Medical Application

“…Chitosan (CS), dopamine (PDA), gelatin (Gel), agarose, sodium hyaluronate (HA), cellulose and alginate not only have good solubility, biocompatibility, and easy modification, but also synthesized antibacterial hydrocolloids have good antibacterial properties, and can release antibacterial agents accurately, and most of them are not resistant to bacteria, so they are often used to prepare antibacterial hydrogels. [183] Vasquez et al studied an in situ generated PEGDA/HA-SH hydrogel, which has antibacterial activity against a variety of gram-positive bacteria (Staphylococcus aureus and 59 strains of Staphylococcus epidermidis), drug-resistant gram-positive bacteria (MRSA and MRSE), gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii) and drug-resistant gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli), and can be used to treat infections. [184] Rahmani et al developed a novel polyurethane/polyethylene glycol (PU/PEG)-based hydrogel with good biocompatibility showing significant anti-Staphylococcus aureus activity, a favorable candidate for wound dressing applications.…”

Design of foam flexible pressure sensor based on PDMS/MWCNTs/HPC/PDA for human motion detection

“…Among the commonly used conductive materials are carbon nanotubes (CNTs), graphene (RGO), metal nanowires, etc. [6,7].…”

Highly sensitive strain sensors based on dispensing technology for human–machine interaction

“…Therefore, it is still a big challenge to obtain a strain sensor that is simple to prepare, low cost, high sensitivity, and high stability. At the same time, human skin is the largest perception network on the human body [9], and traditional human-machine interaction devices often only focus on its interaction effect, while ignoring the comfort and realism of human experience [10][11][12][13][14][15]. With the development of flexible electronic technology, the preparation of sensitive units of sensors has gradually become refined and patterned, which has opened a new journey to explore high-performance flexible strain sensors for humanmachine interaction [16][17][18][19][20].…”