Stretchable and tough conductive hydrogels for flexible pressure and strain sensors

2020 ◽  
Vol 8 (16) ◽  
pp. 3437-3459 ◽  
Author(s):  
Zhenwu Wang ◽  
Yang Cong ◽  
Jun Fu

This review summarises recent advances in stretchable and tough conductive hydrogel sensors for wearable and implantable devices.

2020 ◽  
Vol 8 (39) ◽  
pp. 20474-20485
Author(s):  
Dong Zhang ◽  
Yijing Tang ◽  
Yanxian Zhang ◽  
Fengyu Yang ◽  
Yonglan Liu ◽  
...  

A new fully polymeric conductive hydrogel sensor with IPN structure was developed, which achieved ultra-high stretchability, strong surface adhesion, and high sensing stability in response to both large and subtle human movements.


Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3947 ◽  
Author(s):  
Li Tang ◽  
Shaoji Wu ◽  
Jie Qu ◽  
Liang Gong ◽  
Jianxin Tang

Hydrogels, as classic soft materials, are important materials for tissue engineering and biosensing with unique properties, such as good biocompatibility, high stretchability, strong adhesion, excellent self-healing, and self-recovery. Conductive hydrogels possess the additional property of conductivity, which endows them with advanced applications in actuating devices, biomedicine, and sensing. In this review, we provide an overview of the recent development of conductive hydrogels in the field of strain sensors, with particular focus on the types of conductive fillers, including ionic conductors, conducting nanomaterials, and conductive polymers. The synthetic methods of such conductive hydrogel materials and their physical and chemical properties are highlighted. At last, challenges and future perspectives of conductive hydrogels applied in flexible strain sensors are discussed.


Soft Matter ◽  
2021 ◽  
Author(s):  
Yang Yu ◽  
Fengjin Xie ◽  
Xinpei Gao ◽  
Liqiang Zheng

The next generation of high-performance flexible electronics has put forward new demands to the development of ionic conductive hydrogels. In recent years, many efforts have been made toward developing double-network...


2021 ◽  
Vol 45 (1) ◽  
pp. 208-216
Author(s):  
Zhonghua Zhao ◽  
Xiang Yuan ◽  
Yicheng Huang ◽  
Jikui Wang

Conductive hydrogels are promising flexible conductors for human motion monitoring.


e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 391-397
Author(s):  
Tao Liu ◽  
Ripeng Zhang ◽  
Jianzhi Liu ◽  
Ling Zhao ◽  
Yueqin Yu

Abstract Highly stretched and conductive hydrogels, especially synthetized from natural polymers, are beneficial for highly stretched electronic equipment which is applied in extreme environment. We designed and prepared robust and tough alginate hydrogels (GMA-SA-PAM) using the ingenious strategy of fully interpenetrating cross-linking, in which the glycidyl methacrylate (GMA) was used to modify sodium alginate (SA) and then copolymerized with acrylamide (AM) and methylenebisacrylamide (BIS) as cross-linkers. The complete cross-linked structures can averagely dissipate energy and the polymer structures can maintain hydrogels that are three-dimensional to greatly improve the mechanical performance of hydrogels. The GMA-SA-PAM hydrogels display ultra-stretchable (strain up to ∼407% of tensile strain) and highly compressible (∼57% of compression strain) properties. In addition, soaking the GMA-SA-PAM hydrogel in 5 wt% NaCl solution also endows the conductivity of the hydrogel (this hydrogel was named as GSP-Na) with excellent conductive properties (5.26 S m−1). The GSP-Na hydrogel with high stability, durability, as well as wide range extent sensor is also demonstrated by researching the electrochemical signals and showing the potential for applications in wearable and quickly responded electronics.


Author(s):  
Zexing Deng ◽  
Rui Yu ◽  
Baolin Guo

Stimuli-responsive conductive hydrogel has been emerged as a new surging concept in hydrogel research field due to its combined advantages of stimuli-responsivity and conductivity from conductive polymers (such as polyaniline,...


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1854
Author(s):  
Xiuru Xu ◽  
Chubin He ◽  
Feng Luo ◽  
Hao Wang ◽  
Zhengchun Peng

Robust conductive hydrogels are in great demand for the practical applications of smart soft robots, epidermal electronics, and human–machine interactions. We successfully prepared nanoparticles enhanced polyacrylamide/hydroxypropyl guar gum/acryloyl-grafted chitosan quaternary ammonium salt/calcium ions/SiO2 nanoparticles (PHC/Ca2+/SiO2 NPs) conductive hydrogels. Owing to the stable chemical and physical hybrid crosslinking networks and reversible non-covalent interactions, the PHC/Ca2+/SiO2 NPs conductive hydrogel showed good conductivity (~3.39 S/m), excellent toughness (6.71 MJ/m3), high stretchability (2256%), fast self-recovery (80% within 10 s, and 100% within 30 s), and good fatigue resistance. The maximum gauge factor as high as 66.99 was obtained, with a wide detectable strain range (from 0.25% to 500% strain), the fast response (25.00 ms) and recovery time (86.12 ms), excellent negligible response hysteresis, and good response stability. The applications of monitoring the human’s body movements were demonstrated, such as wrist bending and pulse tracking.


2021 ◽  
Vol 16 (6) ◽  
pp. 861-868
Author(s):  
Mengge Lv ◽  
Xinfang Wei ◽  
Liwen Peng

Conductive hydrogels have shown excellent application prospects in the fields of bioelectronics, tissue engineering, wearable devices, etc. However, its poor compatibility at the organic-inorganic interface affects its mechanical strength and limits its wide application. We prepared carbon fiber-polyacrylamide organic-inorganic composite material by electrochemical polymerization using N,N-methylenebisacrylamide as the crosslinking agent, acrylamide as the monomer, and carbon fiber as the conductive filler. It forms a conductive hydrogel after absorbing water. The effects of monomer concentration, reaction time, and current on the composite material were investigated in this article. The experimental results show that a large number of irregular bumps are produced on the surface of carbon fiber, and various characterization tests show that it is polyacrylamide (PAM) that successfully attached to carbon fiber. Under the same electrochemical polymerization time, the current density and monomer concentration have little effect on the molecular weight which mainly concentrated around 6.2 × 105. The graft modification of PAM reduces the defects on the surface of the carbon fiber, and the composite effect is good.


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