Sensitive, Stretchable, and Sustainable Conductive Cellulose Nanocrystal Composite for Human Motion Detection

Abstract

Sensitive strain sensors (an important component of soft robotics, wearable devices, and biomedical electronics) with high sensitivity, stretchability, and long-term stability are still challenging. A sensitive, stretchable, and sustainable sensor using poly­(3,4-ethylenedioxythiophene) (PEDOT) coated cellulose nanocrystals (CNC) with poly­(vinyl alcohol)/glycerol (PVA/Gly) composite is proposed. The low cost and sustainable PEDOT coated CNC with high aspect ratio lowered the electrical percolation threshold that significantly improved the electrical conductivity leading to better sensitivity (gauge factor = 21.25) compared to the PEDOT applied film without CNC (gauge factor = 9.35). The exceptional stretchability of up to 500% and a low Young’s modulus with long-term stability exceeding 3 months are due to the glycerol plasticizer. The fabricated sensors possessed outstanding real-time strain sensing capability for a series of human motions, including complex joint bending motions, subtle muscle motions, wrist pulse, and excellent self-healing ability. This effective green strategy for preparing a highly stretchable conductive composite addresses current limitations in strain sensor preparation and offers a sustainable approach to sensor design and development.

Self-Standing, Photothermal-Actuating, and Motion-Monitoring Janus Films One-Pot Synthesized by Green Carboxymethyl Glucomannan/Liquid Metal Nanoinks

“…The GF values of CGM/EGaIn films were 31.09, 63.46, and 663.98 during the strain range of 0–2%, 2–4%, and 4–5%, respectively, indicating CGM/EGaIn films exhibited an ultrahigh strain sensitivity at the small strain. Figure e showed that the sensitivity of CGM/EGaIn films was much higher than most of the reported biomass-based sensors. − Therefore, the human motion (such as throat vibrating (Figure f), wrist bending (Figure g) and finger bending (Figure h)) manners can be easily monitored by recording the obvious and regular relative resistance changes of CGM/EGaIn-50% film in a repeatable bending manner.…”

Highly Stretchable, Highly Sensitive, and Antibacterial Electrospun Nanofiber Strain Sensors with Low Detection Limit and Stable CNT/MXene/CNT Sandwich Conductive Layers for Human Motion Detection

“…In addition, electrical stability of the CNT/MXene/CNT/TPU strain sensor is further characterized by the I – V curve under different stretching (Figure S6) and the Δ R / R 0 -strain curve at different stretching rates (Figure S7), which enable the sensor to accurately and timely transmit the signals captured in human motion detection to back-end processing equipment. Additionally, the performances of the CNT/MXene/CNT/TPU strain sensor and recent crack-based strain sensors are compared in terms of sensing range and sensitivity (Figure h), ,,− and the detailed parameters are shown in Table S1. It can be found that crack-based strain sensors are generally unable to combine a wide sensing range and high sensitivity.…”

Recent advances in the construction and application of stretchable PEDOT smart electronic membranes

“…Resistive sensors generally have a faster response time. Lee et al 252 prepared a sensitive, stretchable, and sustainable conductive cellulose nanocrystal composite for human motion detection (Fig. 18a).…”