Synthesis of polyvinyl alcohol (PVA) infiltrated MWCNTs buckypaper for strain sensing application

Abstract

Buckypaper (BP)/polymer composites are viewed as a viable option to improve the strain transfer across the buckypaper strain sensor by means of providing better interfacial bonding between the polymer and carbon nanotubes (CNTs). Multiwall carbon nanotubes (MWCNTs) BP/polyvinyl alcohol (PVA) composites were fabricated by a sequence of vacuum filtration and polymer intercalation technique. The optimized conditions for achieving a uniform and stable dispersion of MWCNTs were found to be using ethanol as a dispersion medium, 54 μm ultrasonic amplitude and 40 min sonication time. FTIR analysis and SEM spectra further confirmed the introduction of oxygenated groups (-COOH) on the surface of MWCNTs BP and the complete infiltration of PVA into the porous MWCNTs network. At MWCNTs content of 65 wt. %, the tensile strength, Young’s modulus and elongation-at-break of PVA-infiltrated MWCNTs BP achieved a maximum value of 156.28 MPa, 4.02 GPa and 5.85%, improved by 189%, 443% and 166% respectively, as compared to the MWCNTs BP. Electrical characterization performed using both two-point probe method and Hall effect measurement showed that BP/PVA composites exhibited reduced electrical conductivity. From the electromechanical characterization, the BP/PVA composites showed improved sensitivity with a gauge factor of about 1.89–2.92. The cyclic uniaxial tensile test validated the high reproducibility and hysteresis-free operation of 65-BP/PVA composite under 3 loading-unloading cycles. Characterization results confirmed that the flexible BP/PVA composite (65 wt. %) with improved mechanical and electromechanical properties is suitable for strain sensing applications in structural health monitoring and wearable technology, as an alternative choice to the fragile nature of conventional metallic strain sensors.

Development of Pressure-Responsive PolyPropylene and Biochar-Based Materials

“…Nonetheless, few research efforts have been devoted to investigate the effect of biochar produced at high temperatures towards the enhancement of polymer conductivity [29]. This field has conducted in-depth studies 2 of 12 on using thermoset-based composites [30][31][32][33] or carbon nanotubes-based thermoplastic polymeric hosts [34][35][36][37][38] but it has neglected to consider thermoplastic and biochar at the same time. The use of a thermoplastic polymer matrix could be very useful for the production of irreversible resistive sensors that could detect the plastic deformation of the material at lower pressure ranges than thermoset-based sensors.…”

A Fully Inkjet-Printed Strain Sensor Based on Carbon Nanotubes

“…Carbon nanotubes (CNTs) possess impressive properties, such as a hundred times higher tensile strength than steel, low electrical conductivity, and good thermal conductivity [1,2]. Many researchers have investigated CNTs as pressure sensors [3,4] and strain sensors [5,6] because of their excellent electromechanical properties. Bu et al reported drop-casting-prepared multi-walled CNT films with a sensitivity of 2.5 for the strain below 0.1% [7].…”

Graphene/PVA buckypaper for strain sensing application

“…The current method of synthesis has provided a solution to the intrinsic tendency of graphene sheets to agglomerate due to van der Waals forces of attraction, the high viscosity of graphene/polymer suspension, and low solubility in solvents. Whereas, the graphene oxide produced initially had essential functional groups to make strong bonds with polyvinyl alcohol and produced a buckypaper stain sensor with strong interfacial bonding among graphene sheets and polymer matrix 17 . Han, et al 18 synthesized Carbon nanotube-based buckypaper infiltrated with a polymer matrix of epoxy resin that helped to achieve significant mechanical properties such as tensile strength, Young's modulus, and elongation-at-break of 146.1 Mpa, 13.8 GPa, and 1.3% respectively.…”