Highly viscoelastic, stretchable, conductive, and self-healing strain sensors based on cellulose nanofiber-reinforced polyacrylic acid hydrogel

Cellulose ◽  
2021 ◽  
Vol 28 (7) ◽  
pp. 4295-4311
Author(s):  
Yue Jiao ◽  
Kaiyue Lu ◽  
Ya Lu ◽  
Yiying Yue ◽  
Xinwu Xu ◽  
...  
Keyword(s):  
Polyacrylic Acid ◽  
Strain Sensors ◽  
Cellulose Nanofiber ◽  
Self Healing

scholarly journals Dynamic Mussel-Inspired Chitin Nanocomposite Hydrogels for Wearable Strain Sensors

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1416 ◽  
Author(s):  
Pejman Heidarian ◽  
Abbas Z. Kouzani ◽  
Akif Kaynak ◽  
Ali Zolfagharian ◽  
Hossein Yousefi
Keyword(s):  
Mechanical Properties ◽  
Polyacrylic Acid ◽  
Strain Sensors ◽  
Self Healing ◽  
Network Stability ◽  
Ferric Ions ◽  
Trade Off ◽  
Nanocomposite Hydrogels ◽  
Healing Efficiency ◽  
Hydrogel Network

It is an ongoing challenge to fabricate an electroconductive and tough hydrogel with autonomous self-healing and self-recovery (SELF) for wearable strain sensors. Current electroconductive hydrogels often show a trade-off between static crosslinks for mechanical strength and dynamic crosslinks for SELF properties. In this work, a facile procedure was developed to synthesize a dynamic electroconductive hydrogel with excellent SELF and mechanical properties from starch/polyacrylic acid (St/PAA) by simply loading ferric ions (Fe3+) and tannic acid-coated chitin nanofibers (TA-ChNFs) into the hydrogel network. Based on our findings, the highest toughness was observed for the 1 wt.% TA-ChNF-reinforced hydrogel (1.43 MJ/m3), which is 10.5-fold higher than the unreinforced counterpart. Moreover, the 1 wt.% TA-ChNF-reinforced hydrogel showed the highest resistance against crack propagation and a 96.5% healing efficiency after 40 min. Therefore, it was chosen as the optimized hydrogel to pursue the remaining experiments. Due to its unique SELF performance, network stability, superior mechanical, and self-adhesiveness properties, this hydrogel demonstrates potential for applications in self-wearable strain sensors.

scholarly journals Highly Viscoelastic, Stretchable, Conductive, and Self-Healing Strain Sensors based on Cellulose Nanofibers-Reinforced Polyacrylic Acid Hydrogel

2021 ◽  
Author(s):  
Yue Jiao ◽  
Kaiyue Lu ◽  
Ya Lu ◽  
Yiying Yue ◽  
Xinwu Xu ◽  
...  
Keyword(s):  
Polyacrylic Acid ◽  
Cellulose Nanofibers ◽  
Strain Sensors ◽  
Self Healing ◽  
Wearable Electronics ◽  
Chemically Modified ◽  
Mechanical And Electrical Properties ◽  
Healing Efficiency ◽  
Hydrogel Matrix ◽  
External Stimuli

Abstract Conductive and self-healing hydrogels are among the emerging materials that mimic the human skin and are important due to their probable prospects in soft robots and wearable electronics. However, the mechanical properties of the hydrogel matrix limit their applications. In this study, we developed a physicochemically dual cross-linked chemically modified-cellulose nanofibers-carbon nanotubes/polyacrylic acid (TOCNF-CNTs/PAA) hydrogel. The TOCNFs acted both as a nanofiller and dispersant to increase the mechanical strength of the PAA matrix and break the agglomerates of the CNTs. The final self-healing and conductive TOCNF-CNTs/PAA-0.7 (mass ratio of CNTs to AA) hydrogel with a uniform texture exhibited highly intrinsic stretchability (breaking elongation to ca. 850%), enhanced tensile properties (ca. 59kPa), ideal conductivity (ca. 2.88S·m− 1) and pressure sensitivity. Besides, the composite hydrogels achieved up to approximately 98.36% and 99.99% self-healing efficiency for mechanical and electrical properties, respectively, without any external stimuli. Therefore, the as-designed multi-functional self-healing hydrogels, combined with stretching, sensitivity, and repeatability, possess the ability to monitor human activity and develop multifunctional, advanced, and commercial products such as wearable strain sensors, health monitors, and smart robots.

scholarly journals A Skin-Inspired Stretchable, Self-Healing and Electro-Conductive Hydrogel with a Synergistic Triple Network for Wearable Strain Sensors Applied in Human-Motion Detection

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1737 ◽  
Author(s):  
Yuanyuan Chen ◽  
Kaiyue Lu ◽  
Yuhan Song ◽  
Jingquan Han ◽  
Yiying Yue ◽  
...  
Keyword(s):  
Polyacrylic Acid ◽  
Cellulose Nanofibrils ◽  
Human Motion ◽  
Strain Sensors ◽  
Current Response ◽  
Oxidized Cellulose ◽  
Self Healing ◽  
Wearable Electronics ◽  
Conductive Hydrogel ◽  
Hydrogel Matrix

Hydrogel-based strain sensors inspired by nature have attracted tremendous attention for their promising applications in advanced wearable electronics. Nevertheless, achieving a skin-like stretchable conductive hydrogel with synergistic characteristics, such as ideal stretchability, excellent sensing performance and high self-healing efficiency, remains challenging. Herein, a highly stretchable, self-healing and electro-conductive hydrogel with a hierarchically triple-network structure was developed through a facile two-step preparation process. Firstly, 2, 2, 6, 6-tetrametylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils were homogeneously dispersed into polyacrylic acid hydrogel, with the presence of ferric ions as an ionic crosslinker to synthesize TEMPO-oxidized cellulose nanofibrils/polyacrylic acid hydrogel via a one-pot free radical polymerization. A polypyrrole conductive network was then incorporated into the synthetic hydrogel matrix as the third-level gel network by polymerizing pyrrole monomers. The hierarchical 3D network was mutually interlocked through hydrogen bonds, ionic coordination interactions and physical entanglements of polymer chains to achieve the target composite hydrogels with a homogeneous texture, enhanced mechanical stretchability (elongation at break of ~890%), high viscoelasticity (maximum storage modulus of ~27.1 kPa), intrinsic self-healing ability (electrical and mechanical healing efficiencies of ~99.4% and 98.3%) and ideal electro-conductibility (~3.9 S m−1). The strain sensor assembled by the hybrid hydrogel, with a desired gauge factor of ~7.3, exhibits a sensitive, fast and stable current response for monitoring small/large-scale human movements in real-time, demonstrating promising applications in damage-free wearable electronics.

scholarly journals Ultra-Stretchable and Self-Healing Anti-Freezing Strain Sensors Based on Hydrophobic Associated Polyacrylic Acid Hydrogels

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6165
Author(s):  
Shuya Yin ◽  
Gehong Su ◽  
Jiajun Chen ◽  
Xiaoyan Peng ◽  
Tao Zhou
Keyword(s):  
Flexible Electronics ◽  
Polyacrylic Acid ◽  
Retention Rate ◽  
Strain Sensors ◽  
Working Environment ◽  
Glycerol Solution ◽  
Self Healing ◽  
Ambient Conditions ◽  
Subzero Temperatures ◽  
Water Glycerol

Water-rich conductive hydrogels with excellent stretchability are promising in strain sensors due to their potential application in flexible electronics. However, the features of being water-rich also limit their working environment. Hydrogels must be frozen at subzero temperatures and dried out under ambient conditions, leading to a loss of mechanical and electric properties. Herein, we prepare HAGx hydrogels (a polyacrylic acid (HAPAA) hydrogel in a binary water–glycerol solution, where x is the mass ratio of water to glycerol), in which the water is replaced with water–glycerol mixed solutions. The as-prepared HAGx hydrogels show great anti-freezing properties at a range of −70 to 25 °C, as well as excellent moisture stability (the weight retention rate was as high as 93% after 14 days). With the increase of glycerol, HAGx hydrogels demonstrate a superior stretchable and self-healing ability, which could even be stretched to more than 6000% without breaking, and had a 100% self-healing efficiency. The HAGx hydrogels had good self-healing ability at subzero temperatures. In addition, HAGx hydrogels also had eye-catching adhesive properties and transparency, which is helpful when used as strain sensors.

scholarly journals Dynamic Nanohybrid-Polysaccharide Hydrogels for Soft Wearable Strain Sensing

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3574
Author(s):  
Pejman Heidarian ◽  
Hossein Yousefi ◽  
Akif Kaynak ◽  
Mariana Paulino ◽  
Saleh Gharaie ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Strain Sensors ◽  
Self Healing ◽  
Nano Materials ◽  
Strain Sensing ◽  
Ferric Ions ◽  
Research Activity ◽  
Adhesion Properties ◽  
High Mechanical Strength ◽  
The Moment

Electroconductive hydrogels with stimuli-free self-healing and self-recovery (SELF) properties and high mechanical strength for wearable strain sensors is an area of intensive research activity at the moment. Most electroconductive hydrogels, however, consist of static bonds for mechanical strength and dynamic bonds for SELF performance, presenting a challenge to improve both properties into one single hydrogel. An alternative strategy to successfully incorporate both properties into one system is via the use of stiff or rigid, yet dynamic nano-materials. In this work, a nano-hybrid modifier derived from nano-chitin coated with ferric ions and tannic acid (TA/Fe@ChNFs) is blended into a starch/polyvinyl alcohol/polyacrylic acid (St/PVA/PAA) hydrogel. It is hypothesized that the TA/Fe@ChNFs nanohybrid imparts both mechanical strength and stimuli-free SELF properties to the hydrogel via dynamic catecholato-metal coordination bonds. Additionally, the catechol groups of TA provide mussel-inspired adhesion properties to the hydrogel. Due to its electroconductivity, toughness, stimuli-free SELF properties, and self-adhesiveness, a prototype soft wearable strain sensor is created using this hydrogel and subsequently tested.

Multifunctional Self-Healing Dual Network Hydrogels Constructed via Host–Guest Interaction and Dynamic Covalent Bond as Wearable Strain Sensors for Monitoring Human and Organ Motions

2021 ◽  
Vol 13 (12) ◽  
pp. 14612-14622
Author(s):  
Xiong Liu ◽  
Zhijun Ren ◽  
Fangfei Liu ◽  
Li Zhao ◽  
Qiangjun Ling ◽  
...  
Keyword(s):  
Covalent Bond ◽  
Strain Sensors ◽  
Self Healing

Ultrastretchable and Self-Healing Conductors with Double Dynamic Network for Omni-Healable Capacitive Strain Sensors

Nano Letters ◽  
2021 ◽  
Author(s):  
Pan-Pan Jiang ◽  
Haili Qin ◽  
Jing Dai ◽  
Shu-Hong Yu ◽  
Huai-Ping Cong
Keyword(s):  
Dynamic Network ◽  
Strain Sensors ◽  
Self Healing ◽  
Capacitive Strain

Low temperature tolerant, ultrasensitive strain sensors based on self-healing hydrogel for self-monitor of human motion

2019 ◽  
Vol 257 ◽  
pp. 116177 ◽  
Author(s):  
Shengping Dai ◽  
Xinghao Hu ◽  
Xiuzhu Xu ◽  
Xiaoting Cao ◽  
Yuewen Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Human Motion ◽  
Strain Sensors ◽  
Self Healing
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