Maintaining the mechanical properties and long-term operational safety is considered the main challenge for composite materials under cyclic loading. This work presents mechanical performance of tri-component composites based on multiwall carbon nanotubes (MWCNTs), carbon fibres (CFs) and epoxy resin, and their electrical conductance property for applications like strain gauges. As a result of incorporation of MWCNTs into the epoxy resin in the composite’s morphology, their electrical, mechanical and piezoresistive performance can indicate the self-sensing of carbon fiber reinforced epoxy resin matrix (CF/Epoxy matrix) composites; and thus its influence has been systematically examined. The inclusion of multiwall carbon nanotubes increased the resin bonding to the surface of the CF’s leading to an increased electrical conductivity and mechanical performances. The piezoresistive performance was significantly influenced by the amount of MWCNTs added to the resin, where the Gauge Factor (GF) with respect to the MWCNTs concentration under cyclic tensile and cyclic bending were in the range of 0.6∼1.5 and 2.5∼5.5 respectively. Moreover, the piezoresistive behaviour of the composite samples showed reasonable sensitivity, stability, and reversibility under cyclic mechanical loading, and the samples withstood more than 500 cycles of load without detectable loss in performance. The exceptional mechanical, electrical and piezoresistive performance and easy manufacturing process of the tri-component composites make them attractive for applications such as self-monitoring structural components.

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This work aims to investigate the structural deterioration of the Carbon Fiber Reinforced Epoxy (CFRE) composite under vibration loading by monitoring the variation of the electrical resistance of the composite. The vacuum assisted resin transfer moulding process is used to fabricate the CFRE composites. Multiwall Carbon Nanotubes (MWCNTs) (0.5% wt) are added to the non-conductive resin to increase its electrical conductivity before CFRE fabrication. The tests were carried out by monitoring the variation in electrical resistance of the CFRE composite at 90 Hz frequency vibration loading. The dispersion of MWCNTs into the matrix and the damage of CFRE composite are illustrated by the SEM images. The results show that the electrical resistance change can be considered as a good indication to detect damage in CFRE (modified with 0.5 wt % MWCNTs) under vibration loading.

Hierarchical aggregates of anatase TiO2 nanoribbons/nanosheets (TiO2-NR) and anatase TiO2 nanoparticles (TiO2-NP) were produced through a one-step solvothermal reaction using acetic acid or ethanol and titanium isopropoxide as solvothermal reaction systems. The crystalline structure, crystalline phase, and morphologies of synthesized materials were characterized using several techniques. According to our findings, both TiO2-NR and TiO2-NP were found to have polycrystalline structures, with pure anatase phases. TiO2-NR has a three-dimensional hierarchical structure made up of aggregates of TiO2 nanoribbons/nanosheets, while TiO2-NP has a nanoparticulate structure. The photocatalytic and photocurrent activities for TiO2-NR and TiO2-NP were investigated and compared with the widely used commercial TiO2 (P25), which consists of anatase/rutile TiO2 nanoparticles, as a reference material. Our findings showed that TiO2-NR has higher photocatalytic and photocurrent performance than TiO2-NP, which are both, in turn, higher than those of P25. Our developed solvothermal method was shown to produce a pure anatase TiO2 phase for both synthesized structures, without using any surfactants or any other assisted templates. This developed solvothermal approach, and its anatase TiO2 nanostructure output, has promising potential for a wide range of energy harvesting applications, such as water pollution treatment and solar cells.