Optical Response of Ultrathin Periodically Aligned Single-Wall Carbon Nanotube Films

MRS Advances ◽  
2020 ◽  
Vol 5 (52-53) ◽  
pp. 2685-2691
Author(s):  
Chandra M. Adhikari ◽  
Igor V. Bondarev
Keyword(s):  
Carbon Nanotubes ◽  
Response Function ◽  
Ultrathin Films ◽  
Dielectric Response ◽  
Volume Fraction ◽  
Plasma Frequency ◽  
Dielectric Response Function ◽  
Wide Range ◽  
The Individual ◽  
Walled Carbon Nanotubes

AbstractWe present a semi-analytical expression for the dielectric response function of quasi-2D ultrathin films of periodically aligned single-walled carbon nanotubes. We derive the response function in terms of the individual nanotube conductivity, plasma frequency, and the volume fraction of carbon nanotubes in the film. The real part of the dielectric response function is negative for a sufficiently wide range of the incident photon energy, indicating that the film behaves as a hyperbolic metamaterial. Inhomogeneous broadening increases the effect.

scholarly journals A New Method for Dispersing Pristine Carbon Nanotubes Using Regularly Arranged S-Layer Proteins

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1346
Author(s):  
Andreas Breitwieser ◽  
Uwe B. Sleytr ◽  
Dietmar Pum
Keyword(s):  
Carbon Nanotubes ◽  
Covalent Modification ◽  
Silica Layer ◽  
Medical Sciences ◽  
Lysinibacillus Sphaericus ◽  
Wide Range ◽  
Catalytic Sites ◽  
Multi Walled Carbon Nanotubes ◽  
Pristine Mwnts ◽  
Walled Carbon Nanotubes

Homogeneous and stable dispersions of functionalized carbon nanotubes (CNTs) in aqueous solutions are imperative for a wide range of applications, especially in life and medical sciences. Various covalent and non-covalent approaches were published to separate the bundles into individual tubes. In this context, this work demonstrates the non-covalent modification and dispersion of pristine multi-walled carbon nanotubes (MWNTs) using two S-layer proteins, namely, SbpA from Lysinibacillus sphaericus CCM2177 and SbsB from Geobacillus stearothermophilus PV72/p2. Both the S-layer proteins coated the MWNTs completely. Furthermore, it was shown that SbpA can form caps at the ends of MWNTs. Reassembly experiments involving a mixture of both S-layer proteins in the same solution showed that the MWNTs were primarily coated with SbsB, whereas SbpA formed self-assembled layers. The dispersibility of the pristine nanotubes coated with SbpA was determined by zeta potential measurements (−24.4 +/− 0.6 mV, pH = 7). Finally, the SbpA-coated MWNTs were silicified with tetramethoxysilane (TMOS) using a mild biogenic approach. As expected, the thickness of the silica layer could be controlled by the reaction time and was 6.3 +/− 1.25 nm after 5 min and 25.0 +/− 5.9 nm after 15 min. Since S-layer proteins have already demonstrated their capability to bind (bio)molecules in dense packing or to act as catalytic sites in biomineralization processes, the successful coating of pristine MWNTs has great potential in the development of new materials, such as biosensor architectures.

Radiative Non-Coaxial Rotation of Magnetohydrodynamic Newtonian Carbon Nanofluid Flow in Porous Medium with Heat and Mass Transfer Effects

2020 ◽  
Vol 9 (4) ◽  
pp. 321-335
Author(s):  
Wan Nura’in Nabilah Noranuar ◽  
Ahmad Qushairi Mohamad ◽  
Sharidan Shafie ◽  
Ilyas Khan ◽  
Lim Yeou Jiann
Keyword(s):  
Carbon Nanotubes ◽  
Mass Transfer ◽  
Porous Medium ◽  
Heat And Mass Transfer ◽  
Nuclear Reactor ◽  
Volume Fraction ◽  
Heating System ◽  
Transform Method ◽  
Rotation System ◽  
Walled Carbon Nanotubes

Non-coaxial rotation system has encountered in various fields such as engineering field in designing advanced cooling and heating system, food processing and mixer machines. In the present study, the effect of the non-coaxial rotation of a vertical disk on the heat and mass transfer of Newtonian nanofluids in a porous medium is analytically discussed. The influence of the magnetic field and thermal radiation is also taken into the consideration. Two different types of nanofluids which are single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) with water as the base fluid are analyzed and compared. Suitable dimensionless variables are utilized to convert the governing partial differential equations associated with the initial and boundary conditions into the dimensionless form. Then, the exact solutions of the dimensionless governing equations are calculated by using the Laplace transform method. A limiting case study of the obtained analytical solutions is constructed to compare with the previously published results to verify its validity. The distributions of the velocity, temperature, and concentration along with the Skin friction, Nusselt number, and Sherwood number due to the variation of the pertinent parameters are displayed and scrutinized through graphs and tables. In the frame of non-coaxial rotation, the nanofluid with the SWCNTs nanoparticles have illustrated a higher rate of heat transfer as compared to MWCNTs nanofluid. Moreover, the heat transmission in the nanofluid has been enhanced by increasing the volume fraction of the nanoparticle and also the intensity of the radiation. This suggests that heating or cooling in a system such as a nuclear reactor can be improved by properly selecting the type of the nanofluid and also the volume fraction of the nanoparticle.

scholarly journals The Effect of Volume Fraction of Single-Walled Carbon Nanotubes on Natural Frequencies of Polymer Composite Cone-Shaped Shell Made from Poly(Methyl Methacrylate)

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
A. H. Meysami ◽  
H. Razavi ◽  
I. Fakhari Golpayegani ◽  
V. Bagheri
Keyword(s):  
Carbon Nanotubes ◽  
Methyl Methacrylate ◽  
Polymer Composite ◽  
Natural Frequencies ◽  
Volume Fraction ◽  
Ritz Method ◽  
Single Walled Carbon Nanotubes ◽  
Poly Methyl Methacrylate ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

In this paper, the effect of volume fraction of single-walled carbon nanotubes on natural frequencies of polymer composite cone-shaped shells made from Poly(Methyl Methacrylate) (PMMA) is studied. In order to determine the characterization of materials reinforced with nanoparticles, the molecular dynamics and mixture rule has been used. The motion equations of composite shell based on the classical thin shells theory using Hamilton’s principle are obtained. Then, using the Ritz method, approximate analytical solution of the natural frequency is presented. Results indicate that the nanotubes have a noticeable effect on the natural frequencies.

Thermal Conductivity Measurement for Carbon-Nanotube Suspensions with 3ω Method

2009 ◽  
Vol 60-61 ◽  
pp. 394-398 ◽  
Author(s):  
Gen Sheng Wu ◽  
Jue Kuan Yang ◽  
Shu Lin Ge ◽  
Yu Juan Wang ◽  
Min Hua Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Volume Fraction ◽  
Aqueous Suspension ◽  
Conductivity Measurement ◽  
3Ω Method ◽  
Conductivity Enhancement ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes

The stable and homogeneneous aqueous suspension of carbon nanotubes was prepared in this study. The stability of the nanofluids was improved greatly due to the use of a new dispersant, humic acid. The thermal conductivity of the aqueous suspension was measured with the 3ω method. The experimental results showed that the thermal conductivity of the suspensions increases with the temperature and also is nearly proportional to the loading of the nanoparticles. The thermal conductivity enhancement of single-walled carbon nanotubes (SWNTs) suspensions is better than that of the multi-walled carbon nanotubes (MWNTs) suspensions. Especially for a volume fraction of 0.3846% SWNTs, the thermal conductivity is enhanced by 40.5%. Furthermore, the results at 30°C match well with Jang and Choi’s model.

scholarly journals Fabrication and Characterization of Polylactic Acid Electrospun Scaffolds Modified with Multi-Walled Carbon Nanotubes and Hydroxyapatite Nanoparticles

Biomimetics ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 43
Author(s):  
Athanasios Kotrotsos ◽  
Prokopis Yiallouros ◽  
Vassilis Kostopoulos
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Polylactic Acid ◽  
Physical And Mechanical Properties ◽  
Polymeric Materials ◽  
Cost Effective ◽  
Electrospinning Process ◽  
Wide Range ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The solution electrospinning process (SEP) is a cost-effective technique in which a wide range of polymeric materials can be electrospun. Electrospun materials can also be easily modified during the solution preparation process (prior SEP). Based on this, the aim of the current work is the fabrication and nanomodification of scaffolds using SEP, and the investigation of their porosity and physical and mechanical properties. In this study, polylactic acid (PLA) was selected for scaffold fabrication, and further modified with multi-walled carbon nanotubes (MWCNTs) and hydroxyapatite (HAP) nanoparticles. After fabrication, porosity calculation and physical and mechanical characterization for all scaffold types were conducted. More precisely, the morphology of the fibers (in terms of fiber diameter), the surface properties (in terms of contact angle) and the mechanical properties under the tensile mode of the fabricated scaffolds have been investigated and further compared against pristine PLA scaffolds (without nanofillers). Finally, the scaffold with the optimal properties was proposed as the candidate material for potential future cell culturing.

On the mechanical properties of functionally graded materials reinforced by carbon nanotubes

2017 ◽  
Vol 232 (9) ◽  
pp. 1632-1646 ◽  
Author(s):  
Saeed Rouhi ◽  
Seyed H Alavi
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Elastic Modulus ◽  
Functionally Graded Materials ◽  
Volume Fraction ◽  
Single Walled Carbon Nanotubes ◽  
Functionally Graded ◽  
Graded Materials ◽  
Single Walled Carbon ◽  
Walled Carbon Nanotubes

In this paper, the elastic properties of functionally graded materials reinforced by single-walled carbon nanotubes are studied. Three different matrices, including steel-silicon, iron-alumina and alumina-zirconia are considered. Besides, the effects of nanotube length, radius and volume fraction on the Young’s modulus of functionally graded matrices reinforced by single-walled carbon nanotubes are investigated. It is observed that short nanotubes not only cannot increase the longitudinal elastic modulus of the matrices, but sometimes decrease their elastic modulus. Of the three selected matrices, steel-silicon matrix would have the most enhancement. Investigation of the effect of nanotube volume fraction on the mechanical properties of nanocomposites shows that increasing the volume fraction of long single-walled carbon nanotube results in increasing the elastic modulus of the nanocomposites.

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