Manufacturing and characterization of novel silicone/natural fabric/graphene‐based functional composites for human body motion sensing

Abstract

This study focuses on the development of strain‐sensors utilizing biodegradable natural fabrics (cotton, flax, and wool) and graphene nanoplatelets (GN) through novel coating techniques. A systematic study on improving the electrical conductivity of natural fiber fabrics to be used as effecting sensing stimuli was conducted by varying the proportions of graphene. To further enhance the conductivity, GN was hybridized with conducting polymers, such as polypyrrole (PPy), polyaniline (PANI), and with carbon black (CB). The electrical conductivity, morphological, and mechanical characterizations were carried composites for detailed comparative analysis. The conductive composites were incorporated into flexible and stretchable silicone elastomer (Ecoflex) to be used as strain sensors. Electromechanical characterizations were carried out on the composite sensors and their performance on different human body motions, including finger, wrist, elbow, and knee movements were assessed. The results showed that the addition of hybrids, such as PPy increased the electrical conductivity in fabrics (for instance, cotton with a conductivity of 1.7 S.cm−1). However, the addition of PANI tends to have a negative effect on the conductivity due to poor ability to deposit on the fiber surface. It was observed that the thermal stability was improved with the addition of conductive particles which gives rise to excellent sensitivity and durability of the composite sensors.

Joule-Heating Effect of Thin Films with Carbon-Based Nanomaterials

“…Additionally, the conductivity continued to improve with the increase in the GNP concentration in the paste, which agrees with observations reported in other works [19][20][21]24]. This improvement can be because the incorporation of GNPs has created a path for the electricity flow, and increasing the concentration of the nanoparticles might have resulted in the formation of a better conductive network, which eased the flow of electrons, leading to the linear rise in the electrical conductivity [21]. The number of the layers also influenced the electrical conductivity; in all the cases, it was evident that the samples with only one layer (0.04 mm to 0.05 mm) displayed the largest value, followed by the second (0.06 mm to 0.08 mm) and third layers (0.08 to 0.11 mm).…”

“…It was observed from Figure 8a,b that the electrical resistivity was reduced, and on the contrary, the electrical conductivity was enhanced, with the addition of GNPs. Additionally, the conductivity continued to improve with the increase in the GNP concentration in the paste, which agrees with observations reported in other works [19][20][21]24]. This improvement can be because the incorporation of GNPs has created a path for the electricity flow, and increasing the concentration of the nanoparticles might have resulted in the formation of a better conductive network, which eased the flow of electrons, leading to the linear rise in the electrical conductivity [21].…”

“…orders [19]. Likewise, in other research works [20,21], graphene was used as filler in polyurethane-based polymers and natural rubber latex [22], with enhanced electrical conductivity of the fabrics. Interestingly, besides cotton fabrics, cotton in the fiber form was mixed with polydimethylsiloxane (PDMS) along with multiwalled carbon nanotubes (MWCNTs) to create a conductive composite [23].…”

A Facile Approach of Fabricating Electrically Conductive Knitted Fabrics Using Graphene Oxide and Textile-Based Waste Material

“…The higher K/S and lower L* represent the effective reduction of GO that changed the colour of the sample into a darker shade from the lighter shade [15,25]. Furthermore, several authors reported that reduced wool/graphene composites exhibited higher electrical conductivity than silk/graphene, cotton/graphene, and flax/graphene composites, which might be due to the effective chemical bonding among various functional groups of GO and wool [15,48,49]. The electrical conductivity of fabricated WPrGOKF produced in this study was found to be superior to some other reported graphene incorporated fabrics, as shown in Table 2.…”

Thermoelectrical properties of graphene knife-coated cellulosic fabrics for defect monitoring in Joule-heated textiles

“…The use of this product makes it possible to tune both thermal and electrical conductivity of the base material, incorporating graphene nanoplatelets(GNP) as part of the coating or the fibers. Some of the most advanced developments use graphene to manufacture sensors and smart textiles, [21][22][23][24][25][26][27] electromagnetic shielding, [28][29][30] and flexible energy production devices. 31,32 Currently, there are several alternatives to incorporate graphene into textile substrates.…”