An Ultra-Stretchable Polyvinyl Alcohol Hydrogel Based on Tannic Acid Modified Aramid Nanofibers for Use as a Strain Sensor

Abstract

The mechanical performance is critical for hydrogels that are used as strain sensors. p-Aramid nanofiber (ANF) is preferable as an additive to the reinforce the mechanical performance of a poly(vinyl alcohol) (PVA). However, due to the limited hydrogen bond sites, the preparation of ultra-stretchable, ANF-based hydrogel strain sensor is still a challenge. Herein, we reported an ultra-stretchable PVA hydrogel sensor based on tea stain-inspired ANFs. Due to the presence of numerous phenol groups in the tannic acid (TA) layer, the interaction between PVA and the ANFs was significantly enhanced even though the mass ratio of TA@ANF in the hydrogel was 2.8 wt‰. The tensile breaking modulus of the PVA/TA@ANF/Ag hydrogel sensor was increased from 86 kPa to 326 kPa, and the tensile breaking elongation was increased from 356% to 602%. Meanwhile, the hydrogel became much softer, and no obvious deterioration of the flexibility was observed after repeated use. Moreover, Ag NPs were formed in situ on the surfaces of the ANFs, which imparted the sensor with electrical conductivity. The hydrogel-based strain sensor could be used to detect the joint movements of a finger, an elbow, a wrist, and a knee, respectively. This ultra-stretchable hydrogel described herein was a promising candidate for detecting large-scale motions.

Aramid Nanofiber/Polypyrrole Composite Films for Broadband EMI Shielding, Wearable Electronics, Joule Heating, and Photothermal Conversion

“…Wearable sensors for strain and pressure have attracted people’s widespread attention due to the demand of disease diagnosis, human body monitoring, and other issues in recent years. ,, Sensing nanomaterials with excellent mechanical properties and conductivity have been efficient conductive components of flexible electronic devices for wearable devices and sensors . The ANF/PPy composite film has good mechanical flexibility and high conductivity, resulting in a potential application in wearable sensors for monitoring the human motions.…”

“…30,48,49 Sensing nanomaterials with excellent mechanical properties and conductivity have been efficient conductive components of flexible electronic devices for wearable devices and sensors. 25 The ANF/PPy composite film has good mechanical flexibility and high conductivity, resulting in a potential application in wearable sensors for monitoring the human motions. The ANF/PPy-4 composite film was chosen to characterize the sensing ability owing to mechanical robustness (ultimate stress of 132 MPa) and electrical conductivity of 3546 S m −1 (as shown in Figures 3e and 4f).…”

“…In addition, Yin et al 24 developed a simple method to prepare fiber/rubber composites and constructed ANF/CNT on the fiber surface, which low-sensitivity ΔR/R 0 (∼0.1%) limits its application in wearable sensors. Miao et al 25 assembled the PVA/TA@ANFs/Ag hydrogels; ΔR/R 0 of the hydrogel strain sensor was 51% used for monitoring the knee. Liu et al 26 prepared a multifunctional material platform based on a composite nanofiber framework, which is applied to the engineering of wearable kirigami electronics, which can achieve measurement of physiological parameters and offer a new opinion to develop advanced wearable systems and human− machine interfaces.…”

Multifunctional aramid nanofibers @ polypyrrole films for broadband frequency electromagnetic interference shielding, wearable electronics, Joule heating and photothermal conversion

“…Wearable sensors for strain and pressure have attracted people's widespread attention due to the demand of disease diagnosis, human body monitor and other issues in recent years, [24,44,45] Sensing nanomaterials with excellent mechanical properties and conductivity have been e cient conductive components of exible electronic devices for wearable devices and sensors. [21] ANF@PPy composite lm has good mechanical exibility and high conductivity, resulting in a potential application in wearable sensor for monitoring the human motions. ANF@PPy-4 lm was chosen to characterize the sensing ability owing to mechanical robustness (ultimate stress of 132 MPa) and conductivity of 3546 S m-1 (as shown in Fig.…”

A Facile One-Pot Preparation and Properties of Nanocellulose-Reinforced Ionic Conductive Hydrogels

“…Polyvinyl alcohol (PVA) is a cheap biopolymer, which is widely used in many fields such as bioengineering, modern medicine, textiles, and garments [ 4 ]. It is easily soluble in biological media and can use various cross-linking agents to form stable new hydrogels based on polyvinyl alcohol [ 5 , 6 ]. In general, the addition of nanomaterials to hydrogel systems is an effective and practical way to improve the mechanical strength of hydrogels.…”