PDMS Sponges with Embedded Carbon Nanotubes as Piezoresistive Sensors for Human Motion Detection

• Published in: Nanomaterials (Basel, Switzerland) Vol. 11; no. 7; p. 1740
• Main Authors: Herren, Blake, Webster, Vincent, Davidson, Eric, Saha, Mrinal C., Altan, M. Cengiz, Liu, Yingtao
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.07.2021; MDPI
• Subjects: Carbon; Carbon nanotubes; Compression; Curing; Dispersion; Durability; Elastomers; Elbow; Elbow (anatomy); Electrical properties; Embedding; Fabrication; Human motion; human motion monitoring; Joints (anatomy); Methods; Microwaves; Motion detection; Motion perception; nanocomposite sponge; Nanocomposites; Nanoparticles; Nanotechnology; Nanotubes; piezoresistive sensor; Polydimethylsiloxane; Polymers; Porosity; Prostheses; Scanning electron microscopy; semiconductors; Sensors; Sponges; Strain rate; Throwing; wearable electronics; United States > US
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano11071740

Porous piezoresistive sensors offer promising flexible sensing functionality, such as human joint motion detection and gesture identification. Herein, a facile fabrication method is developed using a microwave-based rapid porogen removal technique for the manufacturing of porous nanocomposite sponges consisting of polydimethylsiloxane (PDMS) and well-dispersed carbon nanotubes (CNTs). The porogen amounts and CNT loadings are varied to tailor the porosity and electrical properties of the porous sensors. The sponges are characterized by a scanning electron microscope (SEM) to compare their microstructures, validate the high-quality CNT dispersion, and confirm the successful nanofiller embedding within the elastomeric matrix. Sponges with a 3 wt% CNT loading demonstrate the highest piezoresistive sensitivity. Experimental characterization shows that the sponges with low porosity have long durability and minimal strain rate dependence. Additionally, the developed sponges with 3 wt% CNTs are employed for the human motion detection using piezoresistive method. One experiment includes fingertip compression measurements on a prosthetic hand. Moreover, the sensors are attached to the chest, elbow, and knee of a user to detect breathing, running, walking, joint bending, and throwing motions.