scholarly journals Ionic Conductive Organohydrogel With Ultrastretchability, Self-Healable and Freezing-Tolerant Properties for Wearable Strain Sensor

2021 ◽  
Vol 9 ◽  
Author(s):  
Feng Ji ◽  
Min Jiang ◽  
Qingyu Yu ◽  
Xuefang Hao ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Strain Sensor ◽  
Fast Response ◽  
Self Healing ◽  
One Pot ◽  
High Mechanical Strength ◽  
Flexible Sensors ◽  
Healing Property ◽  
Human Motions ◽  
Huge Challenge

Currently, stretchable hydrogel has attracted great attention in the field of wearable flexible sensors. However, fabricating flexible hydrogel sensor simultaneously with superstretchability, high mechanical strength, remarkable self-healing ability, excellent anti-freezing and sensing features via a facile method remains a huge challenge. Herein, a fully physically linked poly(hydroxyethyl acrylamide)-gelatin-glycerol-lithium chloride (PHEAA-GE-Gl-LiCl) double network organohydrogel is prepared via a simple one-pot heating-cooling-photopolymerization method. The prepared PHEAA-GE-Gl-LiCl organohydrogel exhibits favorable stretchability (970%) and remarkable self-healing property. Meanwhile, due to the presence of glycerol and LiCl, the PHEAA-GE-Gl-LiCl organohydrogel possesses outstanding anti-freezing capability, it can maintain excellent stretchability (608%) and conductivity (0.102 S/m) even at −40°C. In addition, the PHEAA-GE-Gl-LiCl organohydrogel-based strain sensor is capable of repeatedly and stably detecting and monitoring both large-scale human motions and subtle physiological signals in a wide temperature range (from −40°C to 25°C). More importantly, the PHEAA-GE-Gl-LiCl organohydrogel-based sensor displays excellent strain sensitivity (GF = 13.16 at 500% strain), fast response time (300 ms), and outstanding repeatability. Based on these super characteristics, it is envisioned that PHEAA-GE-Gl-LiCl organohydrogel holds promising potentials as wearable strain sensor.

scholarly journals Inkjet printed self-healable strain sensor based on graphene and magnetic iron oxide nano-composite on engineered polyurethane substrate

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gul Hassan ◽  
Muhammad Umair Khan ◽  
Jinho Bae ◽  
Ahmed Shuja
Keyword(s):  
Iron Oxide ◽  
Strain Sensor ◽  
Gauge Factor ◽  
Self Healing ◽  
Nano Composite ◽  
Mechanical Fracture ◽  
Magnetic Iron Oxide ◽  
Stretching Factor ◽  
Highly Stretchable ◽  
Healing Property

Abstract In recent years, self-healing property has getting tremendous attention in the future wearable electronic. This paper proposes a novel cut-able and highly stretchable strain sensor utilizing a self-healing function from magnetic force of magnetic iron oxide and graphene nano-composite on an engineered self-healable polyurethane substrate through commercialized inkjet printer DMP-3000. Inducing the magnetic property, magnetic iron oxide is applied to connect between graphene flacks in the nano-composite. To find the best nano-composite, the optimum graphene and magnetic iron oxide blending ratio is 1:1. The proposed sensor shows a high mechanical fracture recovery, sensitivity towards strain, and excellent self-healing property. The proposed devices maintain their performance over 10,000 times bending/relaxing cycles, and 94% of their function are recovered even after cutting them. The device also demonstrates stretchability up to 54.5% and a stretching factor is decreased down to 32.5% after cutting them. The gauge factor of the device is 271.4 at 35%, which means its sensitivity is good. Hence, these results may open a new opportunity towards the design and fabrication of future self-healing wearable strain sensors and their applied electronic devices.

Self-healing and anti-freezing graphene-hydrogel-graphene sandwich strain sensor with ultrahigh sensitivity

2021 ◽  
Author(s):  
Lu Wu ◽  
Mingshuai Fan ◽  
Meijie Qu ◽  
Shuaitao Yang ◽  
Jia Nie ◽  
...  
Keyword(s):  
Strain Sensor ◽  
Smart Material ◽  
Self Healing ◽  
Flexible Sensors ◽  
Ultrahigh Sensitivity ◽  
Application Prospects

Hydrogel with specially designed structures and adjustable properties has been considered as an “smart” material with multi-purpose application prospects, especially in the field of flexible sensors. However, most of hydrogel-based...

scholarly journals Self-Healing Mechanism and Conductivity of the Hydrogel Flexible Sensors: A Review

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 216
Author(s):  
Juan Zhang ◽  
Yanen Wang ◽  
Qinghua Wei ◽  
Yanmei Wang ◽  
Mingju Lei ◽  
...  
Keyword(s):  
Matrix Material ◽  
Environmental Parameters ◽  
The Self ◽  
Self Healing ◽  
Flexible Sensors ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Key Issues ◽  
Healing Property ◽  
Ideal Matrix

Sensors are devices that can capture changes in environmental parameters and convert them into electrical signals to output, which are widely used in all aspects of life. Flexible sensors, sensors made of flexible materials, not only overcome the limitations of the environment on detection devices but also expand the application of sensors in human health and biomedicine. Conductivity and flexibility are the most important parameters for flexible sensors, and hydrogels are currently considered to be an ideal matrix material due to their excellent flexibility and biocompatibility. In particular, compared with flexible sensors based on elastomers with a high modulus, the hydrogel sensor has better stretchability and can be tightly attached to the surface of objects. However, for hydrogel sensors, a poor mechanical lifetime is always an issue. To address this challenge, a self-healing hydrogel has been proposed. Currently, a large number of studies on the self-healing property have been performed, and numerous exciting results have been obtained, but there are few detailed reviews focusing on the self-healing mechanism and conductivity of hydrogel flexible sensors. This paper presents an overview of self-healing hydrogel flexible sensors, focusing on their self-healing mechanism and conductivity. Moreover, the advantages and disadvantages of different types of sensors have been summarized and discussed. Finally, the key issues and challenges for self-healing flexible sensors are also identified and discussed along with recommendations for the future.

scholarly journals Effect of Elasticity on Electrical Properties of Weft-Knitted Conductive Fabrics

2021 ◽  
Vol 29 (1(145)) ◽  
pp. 47-52
Author(s):  
Xiaoxue Han ◽  
Xuhong Miao ◽  
Xiaohan Chen ◽  
Li Niu ◽  
Ailan Wan
Keyword(s):  
Large Scale ◽  
Wearable Sensors ◽  
Test Method ◽  
Polymer Materials ◽  
Electrical Performance ◽  
Flexible Sensors ◽  
Sensing Properties ◽  
Substrate Elasticity ◽  
The Impact ◽  
Human Motions

Because of softness and lightness, various flexible sensors have attracted extensive attention and been widely studied. Sensing mechanism of most wearable sensors is derived from an elastic substrate, such as fabric or polymer materials. Although the mechanical-electrical performance of several flexible sensors has been reported, including sensitivity, linearity hysteresis and repeatability, research on the effects of substrate elasticity on sensor capacity is scarce. In this paper, the impact of spandex content, washing and ironing processing on the elasticity of weft knitted sensors was investigated by the constant- extension test method. Afterwards, differences in sensing properties between diverse elastic sensors under single as well as repeated stretch were reported. The experimental results showed that spandex content does influence the elasticity of knitted fabric, which has a further great effect on sensing properties. A highly elastic sensor is capable of detecting large-scale human motions, while sensors with lower elasticity are opposite, which demonstrates that elastic sensors can be designed and chosen to meet the requirements of detecting and monitoring distinct human motions.

An Efficient and Improved Process for the Synthesis of Itopride Hydrochloride and Trimethobenzamide Hydrochloride

2018 ◽  
Vol 15 (4) ◽  
pp. 572-575 ◽  
Author(s):  
Ponnusamy Kannan ◽  
Samuel I.D. Presley ◽  
Pallikondaperumal Shanmugasundaram ◽  
Nagapillai Prakash ◽  
Deivanayagam Easwaramoorthy
Keyword(s):  
Large Scale ◽  
Hydroxylamine Hydrochloride ◽  
Scale Production ◽  
One Pot ◽  
Hydrochloride Salt ◽  
Environmental Friendly ◽  
Large Scale Production ◽  
Non Ulcer Dyspepsia ◽  
Itopride Hydrochloride ◽  
Yield And Purity

Aim and Objective: Itopride is a prokinetic agent used for treating conditions like non-ulcer dyspepsia. Itopride is administered as its hydrochloride salt. Trimethobenzamide is used for treating nausea and vomiting and administered as its hydrochloride salt. The aim is to develop a novel and environmental friendly method for large-scale production of itopride and trimethobenzamide. Materials and Methods: Itopride and trimethobenzamide can be prepared from a common intermediate 4- (dimethylaminoethoxy) benzyl amine. The intermediate is prepared from one pot synthesis using Phyrdroxybenzaldehye and zinc dust and further reaction of the intermediate with substituted methoxy benzoic acid along with boric acid and PEG gives itopride and trimethobenzamide. Results: The intermediate 4-(dimethylaminoethoxy) benzylamine is prepared by treating p-hydroxybenzaldehyde and 2-dimethylaminoethyl chloride. The aldehyde formed is treated with hydroxylamine hydrochloride. The intermediate is confirmed by NMR and the purity is analysed by HPLC. Conclusion: Both itopride and trimethobenzamide were successfully synthesized by this method. The developed method is environmental friendly, economical for large-scale production with good yield and purity.

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.

scholarly journals Characterization of Steel Slag Filler and Its Effect on Aging Resistance of Asphalt Mastic with Various Aging Methods

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 869
Author(s):  
Minghua Wei ◽  
Shaopeng Wu ◽  
Haiqin Xu ◽  
Hechuan Li ◽  
Chao Yang
Keyword(s):  
Particle Size ◽  
Surface Characterization ◽  
Steel Slag ◽  
Self Healing ◽  
Limestone Filler ◽  
Asphalt Mastic ◽  
Pore Characterization ◽  
Asphalt Mastics ◽  
Healing Property

Steel slag is the by-product of the steelmaking industry, the negative influences of which prompt more investigation into the recycling methods of steel slag. The purpose of this study is to characterize steel slag filler and study its feasibility of replacing limestone filler in asphalt concrete by evaluating the resistance of asphalt mastic under various aging methods. Firstly, steel slag filler, limestone filler, virgin asphalt, steel slag filler asphalt mastic and limestone filler asphalt mastic were prepared. Subsequently, particle size distribution, surface characterization and pore characterization of the fillers were evaluated. Finally, rheological property, self-healing property and chemical functional groups of the asphalt mastics with various aging methods were tested via dynamic shear rheometer and Fourier transform infrared spectrometer. The results show that there are similar particle size distributions, however, different surface characterization and pore characterization in the fillers. The analysis to asphalt mastics demonstrates how the addition of steel slag filler contributes to the resistance of asphalt mastic under the environment of acid and alkaline but is harmful under UV radiation especially. In addition, the pore structure in steel slag filler should be a potential explanation for the changing resistance of the asphalt mastics. In conclusion, steel slag filler is suggested to replace limestone filler under the environment of acid and alkaline, and environmental factor should be taken into consideration when steel slag filler is applied to replace natural fillers in asphalt mastic.

scholarly journals Rapid synchronized fabrication of vascularized thermosets and composites

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mayank Garg ◽  
Jia En Aw ◽  
Xiang Zhang ◽  
Polette J. Centellas ◽  
Leon M. Dean ◽  
...  
Keyword(s):  
Large Scale ◽  
Capillary Flow ◽  
External Heat ◽  
Frontal Polymerization ◽  
Self Healing ◽  
Vascular Networks ◽  
Ambient Conditions ◽  
External Energy ◽  
Imaging Phantoms ◽  
Vascular Structures

AbstractBioinspired vascular networks transport heat and mass in hydrogels, microfluidic devices, self-healing and self-cooling structures, filters, and flow batteries. Lengthy, multistep fabrication processes involving solvents, external heat, and vacuum hinder large-scale application of vascular networks in structural materials. Here, we report the rapid (seconds to minutes), scalable, and synchronized fabrication of vascular thermosets and fiber-reinforced composites under ambient conditions. The exothermic frontal polymerization (FP) of a liquid or gelled resin facilitates coordinated depolymerization of an embedded sacrificial template to create host structures with high-fidelity interconnected microchannels. The chemical energy released during matrix polymerization eliminates the need for a sustained external heat source and greatly reduces external energy consumption for processing. Programming the rate of depolymerization of the sacrificial thermoplastic to match the kinetics of FP has the potential to significantly expedite the fabrication of vascular structures with extended lifetimes, microreactors, and imaging phantoms for understanding capillary flow in biological systems.

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