Theoretical investigation of the density and the heat capacity of [EMIM][BF4] and its MWCNTs ionanofluids: Effect of temperature and MWCNTs concentration

The density and specific heat capacity is an important parameter for heat transfer fluids (HTFs) specially which used for cooling or heating purposes. In this study the density of ethyle methyl imidazolium tetrafluoro borate ionicliquids ([EMIM][BF4]) measured experimentally. In addition, the density (ρ) and the specific heat capacity (Cp) of the ionanofluid (INF) were calculated theoretically. The studied INF composed of multi-walled carbon nanotubes (MWCNTs) dispersed in the ionicliquid (IL) [EMIM][BF4] in the concentrations (0.5%, 1%, 3%, 5%, 7% and 9%). Scanning electron microscopy and differential scanning calorimetry measured for the used MWCNTs. The density and the specific heat capacity of pure [EMIM][BF4] and its INFs were plotted versus temperature in a graphs. The results show that the density of [EMIM][BF4] and its INFs decreased linearly with temperature. The density increased by 0.243%-3.968% for 0.5%-9% MWCNTs concentration in INFs, reaching maximum value of 1.329 g.cm-3 at 20 °C. In contrast the specific heat capacity of [EMIM][BF4] and its INFs increased linearly with temperature with an enhancement of about 0.417%-7.99% for 0.5%-9% concentration of MWCNTs reaching maximum value of 1.812 J/g.K at 358.15K with 9%MWCNT concentration. That’s mean the addition of MWCNT cause increasing both of the density and the specific heat capacity of INF.

The Influence of Zinc Oxide with Carbon Nanotube Composite NanoMaterials on Antibacterial Activity

A novel hybrid substance, ZnO: MWCNT, are fabricated from prepared pellets using a pulsed laser ablation liquid technique at varied MWCNT concentrations (0, 3, 5, 10, and 15) wt%. The study cast at the effect of MWCNT concentration on the structure of prepared samples using FTIR and tested for different types of antimicrobial activity. From FTIR examination, one can observe that all the prepared ZnO: MWCNT samples with different concentrations have different types of band (stretching and bending). All the prepared composite samples with various concentrations have showed influence on different types of bacterial, however in general the annealing ZnO, MWCNT and the composite nanomaterial with 15%MWCNT have higher zone of antibacterial activity for studying types of bacterial inhibition.

Damage Detection of Carbon Nanotube Cementitious Composites Using Thermal and Electrical Resistance Properties

This study aimed to detect damage based on thermal and electrical resistance properties by fabricating composites in which multi-walled carbon nanotubes (MWCNTs) and cement-based materials are mixed. The experimental parameters used were the cement-based material type, MWCNT concentration, curing period, and presence of damage. The experimental results showed that damage in cement paste can be detected using the heat property at every MWCNT concentration, and damage in mortar can be detected at MWCNT concentrations of ≤0.25 wt%. However, damage to concrete is difficult to detect using the heat property. Damage to cement paste, mortar, and concrete can be detected at every concentration using the electrical resistance property. Furthermore, field emission scanning electron microscopy (FE-SEM) results revealed uniformly dispersed MWCNTs inside the composites without agglomeration or the formation of carbon nanotube (CNT) networks.

Heating Performance of Nano-Sidewalk Blocks Containing Carbon Nano Material

Recently, the occurrence of freezing accidents in the winter has increased, as subzero temperatures have decreased rapidly. Several studies have been conducted on the prevention of freezing accidents in the winter. In this study, the heating and electrical performance of nano-sidewalk blocks mixed with multiwalled carbon nanotubes (MWCNTs) were evaluated. The parameters were the curing duration, MWCNT concentration, and supply voltage. The size of the interlocking block specimen was 200 mm × 100 mm × 60 mm. The heating performance of the specimens increased by 12.3 times, with an increase in the MWCNT concentration and supply voltage.

Optimization and assessment of MWCNT dispersion in polypropylene nanocomposite films

Functionalized carbon nanotubes dispersion in polypropylene is optimized and investigated using thresholding based image segmentation. Carbon nanotubes polypropylene films are developed using solution casting method and MWCNT dispersion is optimized upto 1% MWCNT concentration. Dispersion state is investigated by thresholding based image segmentation and agglomeration estimation method applied on scanning electron microscopy (SEM) images. K-means clustering algorithm is applied further to validate the thresholding algorithm by calculating the MWCNT weight % in processed SEM images. It is found that the proposed clustering algorithm can detect MWCNT concentration significantly upto 1%. To further validate the dispersion studies, developed nanocomposite films are used to fabricate the dragonfly inspired artificial flapping wings. The natural frequency was found maximum for 1% MWCNT-COOH-PP wing at 52.27 Hz.

Dispersibility of Multiwall Carbon Nanotube in a Polyanionic Surfactant Based on UV-Vis Analysis

The degree of carbon nanotube (CNT) dispersion in an ink solution plays a critical role in the performance of CNT based devices. This is a challenging task in the CNT utilization due to strong van der Waals interaction affecting the CNT bundles. A good dispersion degree can be achieved, for instance, by lowering the van der Waals interaction with the strategy of non-covalent interaction between polyanionic surfactant and the CNT surface. Herein, a simple and quick technique to disperse multiwall CNT (MWCNT) by using a polyanionic dispersant, carboxymethyl cellulose (CMC), is reported. The dispersion degree of MWCNT in aqueous solution during the sonication process was studied using UV-Vis analysis. Transmission electron microscope (TEM) was also applied to further investigate the interaction between CMC and MWCNT. The result shows that the maximum dispersion of MWCNT was achieved with a maximum absorbance in the UV-Vis spectra. Higher CMC concentration resulted in a higher viscosity of the solution, thus it increased the sonication duration in obtaining the maximum dispersion. By varying the MWCNT concentration at a constant CMC concentration of 0.25 wt.%, a homogenous MWCNT dispersion was obtained up to 0.2 wt.%. The encapsulation of a thin CMC layer on the MWCNT surface with a thickness of 1.5–3 nm was evidenced by TEM micrograph analysis.

Tailoring the Seebeck Coefficient of Spray-Coated Poly(3,4-ethylenedioxythiophene): Poly(styrenesulfonate) Films with Nitrogen Doped Multiwalled Carbon Nanotubes

The thermoelectric properties of flexible thin films fabricated from two commercial poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) formulations filled with multiwalled carbon nanotubes (MWCNT) and nitrogen-doped MWCNT (N-MWCNT) were investigated. A simple spray-coating method for the fabrication of such flexible films on a polyethylene terephthalate substrate was developed. While increasing the MWCNT concentration had little effect on the thermoelectric properties, increasing the N-MWCNT concentration resulted in the emergence of an overall n-type semiconducting behavior and, thereby, tailoring the Seebeck coefficient of the composite films from p-type to n-type was shown. The Seebeck coefficient of the two PEDOT:PSS formulation films was inverted from 4.1 to −13.3 μV/K and from 12.5 to −10.9 μV/K respectively, with increasing N-MWCNT concentration from 0 to 95 wt.%. The importance of these results for future work stems from the possibility of tailoring the behavior of a typical p-type polymer such as PEDOT:PSS and the effect that the polymer conductive grade has on the switching concentration.