Review of Graphene-Based Textile Strain Sensors, with Emphasis on Structure Activity Relationship

Abstract

Graphene-based textile strain sensors were reviewed in terms of their preparation methods, performance, and applications with particular attention on its forming method, the key properties (sensitivity, stability, sensing range and response time), and comparisons. Staple fiber strain sensors, staple and filament strain sensors, nonwoven fabric strain sensors, woven fabric strain sensors and knitted fabric strain sensors were summarized, respectively. (i) In general, graphene-based textile strain sensors can be obtained in two ways. One method is to prepare conductive textiles through spinning and weaving techniques, and the graphene worked as conductive filler. The other method is to deposit graphene-based materials on the surface of textiles, the graphene served as conductive coatings and colorants. (ii) The gauge factor (GF) value of sensor refers to its mechanical and electromechanical properties, which are the key evaluation indicators. We found the absolute value of GF of graphene-based textile strain sensor could be roughly divided into two trends according to its structural changes. Firstly, in the recoverable deformation stage, GF usually decreased with the increase of strain. Secondly, in the unrecoverable deformation stage, GF usually increased with the increase of strain. (iii) The main challenge of graphene-based textile strain sensors was that their application capacity received limited studies. Most of current studies only discussed washability, seldomly involving the impact of other environmental factors, including friction, PH, etc. Based on these developments, this work was done to provide some merit to references and guidelines for the progress of future research on flexible and wearable electronics.

Keywords: fabric; graphene-based; staple and filament yarn; staple fiber; textile strain sensors.

Figure 1

The development trend of carbon-based strain sensors in recent five years.

Figure 2

The general trend of GF absolute value of textile strain sensors according to their structure variation.

Figure 3

Fabrication and performance of graphene-based textile strain sensors. (a) Schematic illustration showing the fabrication of PGFs via a phase separation method. “Adapted with permission from reference [57]. Copyright [2019], Advanced Functional Materials”. (b) Schematic illustration for preparing poly (styrene-butadiene-styrene)/graphene composite fibers through a wet-spinning method. “Adapted with permission from reference [45]. Copyright [2020], Macromolecular Materials and Engineering”. (c) Durability of the PGFs strain sensors after 6000 cycles at a 1% strain stretch and release. “Adapted with permission from reference [57]. Copyright [2019], Advanced Functional Materials”. (d) Stability of the rGOFF strain sensor under a repeated applied strain of 20.0%. “Adapted with permission from reference [46]. Copyright [2019], ACS Applied Materials & Interfaces”. (e) Schematic diagram of CVD method. “Adapted with permission from reference [107]. Copyright [2009], Nano Letters”. (f) Schematic diagram of dip-coating method. “Adapted with permission from reference [108]. Copyright [2020], ACS Applied Materials & Interfaces”.

Figure 4

Applications of graphene-based textile strain sensors. (a) Relative resistance changes of the elbow joint bending. “Adapted with permission from reference [45]. Copyright [2020], Macromolecular Materials and Engineering”. (b) Relative resistance changes of the CFSS to wrist bending. “Adapted with permission from reference [82]. Copyright [2020], ACS Applied Materials & Interfaces”. (c) Responsive curves of wearable sensor on the knee under motions of flexing/extending, walking, jogging, jumping, and squatting-jumping. “Adapted with permission from reference [65]. Copyright [2015], Advanced materials”. (d) Responsive curves of the graphene-silk fabric strain sensor to eyes blinking, mouth opening and closing, laughing and crying. “Adapted with permission from reference [79]. Copyright [2019], Advanced Materials Interfaces”. (e) Responsive curves of wearable sensors during the robot’s dance “Gangnam Style”: Elbow (black line), waist (redline), and knee (blue line). “Adapted with permission from reference [65]. Copyright [2015], Advanced materials”. (f) Relative resistance changes with various movements of the motion glove containing the fabric-based sensors, such as pressing, bending, grabbing, and up, down, and rotation of the wrist. “Adapted with permission from reference [83]. Copyright [2018], ACS Applied Materials & Interfaces”.