scholarly journals Flexible Electrode Based on MWCNT Embedded in a Cross-Linked Acrylamide/Alginate Blend: Conductivity vs. Stretching

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 181 ◽  
Author(s):  
Jake Thibodeau ◽  
Anna Ignaszak
Keyword(s):  
Mechanical Analysis ◽  
Carbon Films ◽  
Flexible Electrode ◽  
Mwcnt Content ◽  
Electronic Conductivities ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Maximum Content ◽  
Elastic Polymer

A polyacrylamide-alginate hydrogel electrolyte, blended with Multi-Walled Carbon Nanotubes (MWCNT) as an electronically conductive fraction, allows for the creation of a flexible, durable, and resilient electrode. The MWCNT content is correlated with mechanical characteristics such as stretch modulus, tensile resistance, and electrical conductivity. The mechanical analysis demonstrates tensile strength that is comparable to similar hydrogels reported in the literature, with increasing strength for MWCNT-embedded hydrogels. The impedance spectroscopy reveals that the total resistance of electrodes decreases with increasing MWCNT content upon elongation and that bending and twisting do not obstruct their conductivity. The MWCNT-inserted hydrogels show mixed ionic and electronic conductivities, both within a range of 1–4 × 10−2 S cm−1 in a steady state. In addition, the thermal stability of these materials increases with incrementing MWCNT content. This observation agrees with long-term charge-discharge cycling that shows enhanced electrochemical durability of the MWCNT-hydrogel hybrid when compared to pure hydrogel electrolyte. The hydrogel-carbon films demonstrate an increased interfacial double-layer current at a high MWCNT content (giving an area-specific capacitance of ~30 mF cm−2 at 2.79 wt.% of MWCNT), which makes them promising candidates as printable and flexible electrodes for lightweight energy storage applications. The maximum content of MWCNT within the polymer electrolyte was estimated at 2.79 wt.%, giving a very elastic polymer electrode with good electrical characteristics.

scholarly journals Continuous Long-Term Exposure to Low Concentrations of MWCNTs Induces an Epithelial-Mesenchymal Transition in BEAS-2B Cells

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1742
Author(s):  
Hélène Barthel ◽  
Christian Darne ◽  
Laurent Gaté ◽  
Athanase Visvikis ◽  
Carole Seidel
Keyword(s):  
Epithelial Mesenchymal Transition ◽  
Mesenchymal Transition ◽  
Pulmonary Exposure ◽  
Adverse Health Effects ◽  
Low Concentrations ◽  
Mitotic Abnormalities ◽  
Epithelial Marker ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In the field of nanotechnology, the use of multi-walled carbon nanotubes (MWCNTs) is growing. Pulmonary exposure during their production, use, and handling is raising concerns about their potential adverse health effects. The purpose of this study is to assess how the physical characteristics of MWCNTs, such as diameter and/or length, can play a role in cellular toxicity. Our experimental design is based on the treatment of human bronchial epithelial cells (BEAS-2B) for six weeks with low concentrations (0.125–1 µg/cm2) of MWCNTs having opposite characteristics: NM-403 and Mitsui-7. Following treatment with both MWCNTs, we observed an increase in mitotic abnormalities and micronucleus-positive cells. The cytotoxic effect was delayed in cells treated with NM-403 compared to Mitsui-7. After 4–6 weeks of treatment, a clear cellular morphological change from epithelial to fibroblast-like phenotype was noted, together with a change in the cell population composition. BEAS-2B cells underwent a conversion from the epithelial to mesenchymal state as we observed a decrease in the epithelial marker E-cadherin and an increased expression of mesenchymal markers N-cadherin, Vimentin, and Fibronectin. After four weeks of recovery, we showed that the induced epithelial-mesenchymal transition is reversible, and that the degree of reversibility depends on the MWCNT.

Experimental Investigation of Morphological and Electrical Characteristics of PS/MWCNT Nanocomposite Films

2018 ◽  
Vol 915 ◽  
pp. 104-109
Author(s):  
Barış Demirbay ◽  
Şaziye Uğur
Keyword(s):  
Annealed Film ◽  
Nanocomposite Films ◽  
Electrical Characteristics ◽  
Liquid Form ◽  
Mwcnt Content ◽  
Electrical Percolation ◽  
Glass Substrates ◽  
Multi Walled Carbon Nanotubes ◽  
Electrical Percolation Threshold ◽  
Walled Carbon Nanotubes

Electrical characteristics and morphology of nanocomposite films composed of two different polystyrene (PS) latexes impregnated with multi-walled carbon nanotubes (MWCNT) in the range between 0 wt% and 20 wt% were assessed by considering photon transmission (UV-Vis) technique and electrical conductivity measurements. Emulsion polymerization technique was employed both to synthesize very fine PS particles dispersed in water and to tailor the sizes of the PS particles as 382 nm and 560 nm, respectively. PS/MWCNT nanocomposite films were obtained from the liquid form on glass substrates via drop-casting method and all they dried at 40 QUOTE C. Each dried sample was then annealed at varying temperatures between 100 QUOTE C and 250 QUOTE C for 10 min. The surface conductivity QUOTE of each annealed film at 250 QUOTE C was measured and was found to increase dramatically above a certain mass fraction of MWCNT content, QUOTE . Each set of PS/MWCNT nanocomposite film had a similar electrical percolation threshold of QUOTE =1.5 wt% as the MWCNT content and critical exponents of QUOTE were found to be 2.64 and 1.19 for 382 nm and 560 nm PS latex systems, respectively.

scholarly journals Polymeric Composites Based on Polyurea Matrix Reinforced with Carbon Nanotubes

2017 ◽  
Vol 54 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Maria Adina Vulcan ◽  
Celina Damian ◽  
Paul Octavian Stanescu ◽  
Eugeniu Vasile ◽  
Razvan Petre ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

This paper deals with the synthesis of polyurea and its use as polymer matrix for nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Two types of materials were obtained during this research, the first cathegory uses the polyurea as matrix and the second one uses a mixture between epoxy resin and polyurea. The nanocomposites were characterized by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and Tensile Tests .The elastomeric features of nanocomposites were highlighted by the results which showed low value of Tg. Also higher thermal stability with ~40oC compared with commercial products (M20) were observed, but lower mechanical properties compared to neat polyurea.

The Effect of CNT Content on the Tribological Properties of CNTs Doped Diamond-Like Carbon Films

2015 ◽  
Vol 642 ◽  
pp. 231-235
Author(s):  
Che Hung Wei ◽  
Jui Feng Yang ◽  
Chao I Wang
Keyword(s):  
Friction Coefficient ◽  
Critical Load ◽  
Internal Stress ◽  
Tribological Properties ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Diamond Like Carbon ◽  
Element Analysis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Diamond-like carbon (DLC) films is useful in many applications. To improve the tribological properties in DLC, we spin coat the multi-walled carbon nanotubes (CNTs) with different solution on (100) silicon. DLC was deposited by plasma enhanced chemical vapor deposition (PECVD) with C2H2and H2. The results show that the ID/IGratio is increasing with higher CNTs content while the friction coefficient and critical load are decreasing with larger CNTs contents. The decreasing friction coefficient results from graphitation on the surface due to higher sp2content. The decreasing critical load is attributed to higher internal stress. The effect of friction coefficient and CNT concentration on stress distribution is studied by a nanoscratch finite element analysis. The results indicate that low friction coefficient and high CNT concentration will reduce the stress magnitude in the film. Therefore, the decreasing friction coefficient in CNT doped DLC film with increasing CNT concentration should reduce stress in the film and is good for adhesion. The discrepancy between friction coefficient and critical load is explained in terms of high internal stress during deposition. A surface treatment on CNT before deposition to reduce internal stress is currently under investigation.

Dielectric and Thermomechanical Properties of Polypropylene/Multi-Walled Carbon Nanotubes Nanocomposites

2007 ◽  
Vol 1056 ◽  
Author(s):  
A. Kanapitsas ◽  
E. Logakis ◽  
C. Pandis ◽  
I. Zuburtikudis ◽  
P. Pissis ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Percolation Threshold ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Dielectric Relaxation Spectroscopy ◽  
Melt Mixing ◽  
Polypropylene Nanocomposites ◽  
Multi Walled Carbon Nanotubes ◽  
Permittivity Measurements ◽  
Walled Carbon Nanotubes

ABSTRACTThe purpose of this work is to examine the dielectric, electrical and thermo-mechanical properties of multi-walled carbon nanotubes (MWCNT) filled polypropylene nanocomposites formed by melt-mixing. To that aim dielectric relaxation spectroscopy (DRS) and dymamic mechanical analysis (DTMA) were employed. The results are discussed in terms of nucleating action of MWCNT and interfacial polymer-filler interactions. Special attention is paid to percolation aspects by both ac conductivity measurements for the samples which are above the percolation threshold and permittivity measurements for the samples which are below percolation threshold.

Long-term pulmonary exposure to multi-walled carbon nanotubes promotes breast cancer metastatic cascades

2019 ◽  
Vol 14 (7) ◽  
pp. 719-727 ◽  
Author(s):  
Xuefei Lu ◽  
Yong Zhu ◽  
Ru Bai ◽  
Zhengsheng Wu ◽  
Wenchang Qian ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Carbon Nanotubes ◽  
Pulmonary Exposure ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Characterization of Vinyl Ester/Jute Fiber Bio-Composites in the Presence of Multi-Walled Carbon Nanotubes

2017 ◽  
Vol 730 ◽  
pp. 221-225
Author(s):  
Mohamed Bassyouni ◽  
Shereen M.S. Abdel-Hamid ◽  
Mohamed H. Abdel-Aziz ◽  
M.Sh. Zoromba
Keyword(s):  
Carbon Nanotubes ◽  
Storage Modulus ◽  
Vinyl Ester ◽  
Loss Modulus ◽  
Weight Ratio ◽  
Mechanical Analysis ◽  
Jute Fiber ◽  
Multi Walled Carbon Nanotubes ◽  
Fiber Reinforcements ◽  
Walled Carbon Nanotubes

In this study, vinyl ester –Jute fiber biocomposites were prepared using vacuum-assisted resin infusion (VARI) process. Woven Jute fibers were used with mass fraction 0.68. Multi-walled carbon nanotubes (MWCNTs) are added to the resin with weight ratio 0.5: 99.5 to investigate the thermo-mechanical properties of bio-composites. Storage and loss modulus of vinyl ester bio-composites were investigated in the presence MWCNTs over a range of temperature (25 to 160 oC) to measure the capacity of bio-composite to store and dissipate energy. Damping properties of vinyl ester bio-composites were studied in terms of tan (d). Viscoelastic test using dynamic mechanical analysis (DMA) showed that the glass transition temperature increases with the addition of MWCNTs up to 112.4 oC. Addition of jute fiber reinforcements improves the storage modulus value of vinyl ester more than 65% at room temperature. Significant improvement in storage modulus was found in the presence of MWCNTs.

PZT / MWNTs / EP Piezoelectric Damping Composites Conductivity and Dynamic Mechanical Analysis

2013 ◽  
Vol 668 ◽  
pp. 70-74
Author(s):  
Chong Guang Zang ◽  
Xian Peng Cao
Keyword(s):  
Loss Factor ◽  
Performance Test ◽  
Mechanical Performance ◽  
Piezoelectric Effect ◽  
Ceramic Powder ◽  
Mechanical Analysis ◽  
Dissipation Mechanism ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

According to piezoelectricity and electrical conductivity theory, the ternary system piezoelectric damping composites containing piezoelectric ceramic powder (PZT) / multi-walled carbon nanotubes (MWNTs) / epoxy resin (EP) were developed. Through the conductive and mechanical performance test of composites, the paper showed the piezoelectric damping energy dissipation mechanism of polymer composites. Results indicated that: the loss factor of materials would increase with the increasing of PZT content. When the content of PZT exceeded a certain value, tanδ would increase dramatically. When the content of MWNTs is 2%, tanδ reached a high value. This meant composites played the role of shock absorbing by conducting electricity from piezoelectric effect of PZT to external circuit.

scholarly journals Mechanical Performance of Cementitious Composites by MWCNTs Addition for Structural Applications

2020 ◽  
Vol 9 (2) ◽  
pp. 51-62
Author(s):  
Mohd Moonis Zaheer
Keyword(s):  
Mechanical Performance ◽  
Optimum Concentration ◽  
Sem Images ◽  
Mwcnt Content ◽  
Disperse Carbon ◽  
Structural Applications ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Nano Tubes ◽  
Strength And Durability ◽  
Walled Carbon Nanotubes

This paper presents the investigation on the behaviour of a prism reinforced with multi walled carbon nanotubes (MWCNTs) to study mainly the strength and durability aspects for structural applications. Prisms were made by varying the MWCNT content from 0.1 to 0.5% by weight of cement. Ultrasonic energy was employed to disperse carbon nano tubes (CNTs) in water. For evaluating mechanical property such as load-deflection, tests were performed on CNT admixed prisms under flexure. The outcomes were then compared with plain mortar prisms. An attempt has also been made to explore the optimum concentration of MWCNT additions that will give ideal performance with respect to mechanical and durability properties. Flexural and compressive strength is enhanced by 25% and 19%, respectively compared to control prisms at 28 days when CNT was used in the cementitious matrix. Both porosity and water absorption are reduced by about 25% at 28 days. Based on the parametric study, a tentative optimum CNT concentration (0.3% by weight of cement) has been proposed. SEM images shows perfect crack bridging mechanism; several of the CNTs were shown as crack arrestor across the fine cracks along with some CNTs breakage.

scholarly journals Thermophysical Properties of Nanofluids Composed of Ethylene Glycol and Long Multi-Walled Carbon Nanotubes

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 241
Author(s):  
Karolina Brzóska ◽  
Bertrand Jóźwiak ◽  
Adrian Golba ◽  
Marzena Dzida ◽  
Sławomir Boncel
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Chemical Vapor ◽  
Step Method ◽  
Mwcnt Content ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes ◽  
Rotary Viscometer

In this work, thermal conductivity, viscosity, isobaric heat capacity, and density of stable carbon-based nanofluids are presented. The nanofluids under study are composed of 1,2-ethanediol (ethylene glycol, EG) and long multi-walled carbon nanotubes (MWCNTs), so-called ‘in-house 16h’ (synthesized in our laboratory via catalytic chemical vapor deposition during 16 h with a diameter of 60–80 nm and length of 770 μm). Poly(N-vinylpyrrolidone) (PVP) was used to increase the stability of nanofluids. The nanofluids were prepared via an ultrasonication-assisted, three-step method while their key thermophysical characteristics were obtained using the hot-wire technique and rotary viscometer. As a result, the addition of MWCNTs significantly improved the thermal conductivity of nanofluids by 31.5% for the highest 1.0 wt% (0.498 vol%) long MWCNT content, leaving the Newtonian character of the nanofluids practically intact.

Sign in / Sign up

Export Citation Format

Share Document