The demand for highly flexible and self-powered wearable textile devices has increased in recent years. Graphene coated textile-based wearable devices have been used for energy harvesting and storage due to their outstanding mechanical, electrical and electronic properties. However, the use of metal based nanocomposites is limited in textiles, due to their poor bending, fixation, and binding on textiles. We present here reduced graphene oxide (rGO) as an n-type and conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as a p-type material for a wearable thermoelectric nanogenerator (TEG) using a (pad–dry–cure) technique. We developed a reduced graphene oxide (rGO) coated textile-based wearable TEG for energy harvesting from low-grade human body heat. The conductive polymer (PEDOT:PSS) and (rGO) nanocomposite were coated using a layer by layer approach. The resultant fabric showed higher weight pickup of 60–80%. The developed textile based TEG device showed an enhanced Seebeck coefficient of (25–150 μV K⁻¹), and a power factor of (2.5–60 μW m⁻¹ K⁻¹). The developed TE device showed a higher potential to convert the low-grade body heat into electrical energy, between the human body temperature of (36.5 °C) and an external environment of (20.0 ± 5 °C) with a temperature difference of (2.5–16.5 °C). The wearable textile-based TEG is capable of producing an open circuit output voltage of 12.5–119.5 mV at an ambient fixed temperature of (20 °C). The rGO coated textile fabric also showed reduced electrical sheet resistance by increasing the number of dyeing cycles (10) and increased with the number of (20) washing cycles. The developed reduced graphene oxide (rGO) coated electrodes showed a sheet resistance of 185–45 kΩ and (15 kΩ) for PEDOT:PSS–rGO nanocomposites respectively. Furthermore, the mechanical performance of the as coated textile fabric was enhanced from (20–80 mPa) with increasing number of padding cycles. The thermoelectric performance was significantly improved, without influencing the breath-ability and comfort properties of the resultant fabric. This study presents a promising approach for the fabrication of PEDOT:PSS/rGO nano-hybrids for textile-based wearable thermoelectric generators (TEGs) for energy harvesting from low-grade body heat.

The use of self-powering wearable devices has increased in recent years due to the increasing demands of the internet of things (IOTs). Textile fabrics have shown increasing trends toward wearable electronics due to their outstanding mechanical, electrical, and electronic properties. Herein, we report the development of a highly flexible and washable thermoelectric device with a sheet resistance of 185–45 kΩ. The sheet resistance of the rGO-coated fabric was reduced from 185 to 45 kΩ on coating with PEDOT:PSS, and was further decreased from 45 kΩ to 25 kΩ with 10 padding cycles. The fabric showed a higher wet pickup percentage of 60–80%, which improved the electrical and thermoelectric performance of the resultant textile. The sheet resistance remained stable for up to 20 cycles and then increased (25Ω–180 kΩ). A difference was attained between the human body temperature (T_h) of 36.5 °C with a temperature gradient (ΔT) of 16.5 °C and an ambient temperature of 20.0 ± 0.5 °C. The performance of the device was significantly improved with an enhanced thermoelectric Seebeck coefficient of 2.5–25.0 μV K⁻¹, power factor of 0.25–0.60 μW m⁻¹ K⁻², and figure of merit (ZT) of 0.02–0.08 × 10⁻³. There was an improvement in the tensile strength of the rGO-coated fabric from 20 to 60 mPa, and in the water contact angle (WCA) from 121° to 152°, with a slightly reduced air permeability of 173 to 165 cm³ S² s⁻¹, without influencing the comfort properties. The study demonstrates that the graphene and polymer nanocomposite-coated textile fabric can be used as a self-powered wearable thermoelectric generator for energy harvesting from low-grade human body heat.

A full biocomposite was fabricated from Cordenka CR fibre and furan resin. High fibre mass fractions (FMF) were achieved by pressing the CR fibres into unidirectional sheets prior to incorporation into the resin. Results of testing indicated that the tensile properties of the biocomposite were improved by the initial increase of FMF from 51 to 64%, with a subsequent increase of FMF to 75% resulting in a deterioration of those properties. Examination of the tensile fracture surfaces with a scanning electron microscope (SEM) revealed moderate deterioration in fibre-matrix adhesion after the initial increase of FMF. Further increase of the FMF to 75% was shown by SEM to result in worse fibre-matrix adhesion. On the other hand, the flexural, interlaminar-shear, and dynamic mechanical properties were adversely affected by the increase in fibre-mass fraction from 51 through 75%. These effects were mainly attributed to reduced fibre wetting that resulted in weakened fibre-matrix interfacial bonding and subsequent poor stress exchange at the fibre-matrix interface. Observations made with a digital microscope revealed normal crack behaviour in the laminated composite, and the shear fracture modes were I and II. This biocomposite has mechanical properties comparable to those of flax and glass fibre-reinforced furan resin biocomposites.

The graphene based highly conductive and flexible devices has received momentous attraction and growth in recent years for potential multifunctional uses. The development of flexible and washable textile sensors, actuators, energy storage and energy harvesting systems. Textile fabrics coated with graphene and conductive polymers have been used for wearable self-powered e-textiles, such as tribo-electric, piezoelectric, and Thermoelectric. Herein this research, 100% woven cotton fabric is Fictionalized with graphene oxide (GO) using industrial-scale cold pad batch dyeing technique for the development of low-grade body heat into self-powered wearable e-textiles. The conductive polymer PEDOT: PSS was coated using layer by layer approach. The study demonstrates that the resultant textile electrodes showed reduced electrical sheet resistance from 2.5 MΩ to 15KΩ, with a reduced graphene oxide and further reduced to (2.5 -12.5 Ω) for conductive polymer. The sheet resistance was decreased with the number of dyeing cycles (10-15) and increased with 20 washing cycles vice versa. The study demonstrates that the sensor response and performance were improved with increasing the content percent of rGO and PEDOT: PSS. The tensile strength of as coated fabric electrodes was improved from (25.0-85.5 mPa) and fabric thickness was increased to (26-38µm) without compromising or influencing the air permeability. The resultant textile electrodes may potentially be used in smart textiles for self-powered flexible wearable generators, sensors, and energy storage. The study demonstrates that the cold pad batch dyeing method is a suitable and effective method for the fabrication of graphene-based textiles.

The solution casting method was used to prepare polylactic acid/modified nanocrystalline cellulose (PLA/mNCC) composites, and the effects of the mNCC content on the morphology, thermal characteristics, and rheological properties of the PLA nanocomposite were examined. The PLA microcellular foaming nanocomposite was prepared using supercritical CO₂ foaming. Furthermore, the foaming conditions were optimized, and the effect of NCC surface modification, as well as the content and interfacial force of nanoparticles, on the foaming efficiency and cell pattern of composites was examined. The results suggested that a sufficient number of nanoparticles increased the nucleation site for foaming and played a vital role in heterogeneous nucleation in the foaming system. An ideal microcellular foaming material with an average cell diameter of 6.97μm and a cell density of 6.0510⁹ cells/cm³ was prepared when the foaming temperature was 110C, the foaming pressure was 18MPa, the incubation period was 2h, and the mNCC content was 6.