SILK FIBROIN FILMS CRYSTALLIZED BY MULTIWALLED CARBON NANOTUBES

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1807-1812 ◽  
Author(s):  
H.-S. KIM ◽  
W.-I. PARK ◽  
Y. KIM ◽  
H.-J. JIN
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Silk Fibroin ◽  
Composite Films ◽  
Tensile Modulus ◽  
Multiwalled Carbon ◽  
Regenerated Silk Fibroin ◽  
Silk Films ◽  
Β Sheet

Silk films prepared from regenerated silk fibroin are normally stabilized by β-sheet formation through the use of solvents (methanol, water etc.). Herein, we report a new method of preparing water-stable films without a β-sheet conformation from regenerated silk fibroin solutions by incorporating a small amount (0.2 wt%) of multiwalled carbon nanotubes (MWCNTs). To extend the biomaterial utility of silk proteins, forming water-stable silk-based materials with enhanced mechanical properties is essential. Scanning electron microscopy and transmission electron microscopy were used to observe the morphology of the MWCNT-incorporated silk films. The wide-angle X-ray diffraction provided clear evidence of the crystallization of the silk fibroin induced by MWCNT in the composite films without any additional annealing processing. The tensile modulus and strength of the composite films were improved by 108% and 51%, respectively, by the incorporation of 0.2 wt% of MWCNTs, as compared with those of the pure silk films. The method described in this study will provide an alternative means of crystallizing silk fibroin films without using an organic solvent or blending with any other polymers, which may be important in biomedical applications.

Investigation of thermal and tensile properties of poly(benzimidazole-imide) composites incorporating salicylic acid–functionalized multiwalled carbon nanotubes

2016 ◽  
Vol 30 (2) ◽  
pp. 139-152
Author(s):  
Mohammad Ali Takassi ◽  
Amin Zadehnazari
Keyword(s):  
Carbon Nanotubes ◽  
Salicylic Acid ◽  
Multiwalled Carbon Nanotubes ◽  
Composite Films ◽  
Tensile Modulus ◽  
High Yield ◽  
Multiwalled Carbon ◽  
Solvent Free Conditions ◽  
Amino Salicylic Acid ◽  
Functionalized Multiwalled Carbon Nanotubes

This work describes a novel aromatic poly(benzimidazole-imide) (PBII) with amino salicylic acid (ASA) segments in the main chain by melt/solid polymerization method under solvent-free conditions and its composites reinforced with ASA-functionalized multiwalled carbon nanotubes (MWCNTs-ASA). The polymer was obtained in high yield with an amorphous morphology, was soluble in various organic solvents, such as N,N′-dimethylacetamide, N,N′-dimethylformamide, N-methyl-2-pyrrolidone, and dimethyl sulfoxide, and could afford flexible and tough film via solution casting. MWCNT-ASA/PBII composite films were also prepared by casting a solution of precursor polymer containing different fractions of MWCNTs-ASA into a thin film (1, 2, and 5 wt%). The cast films exhibited good mechanical properties with tensile strengths of 90.00–128.3 MPa, elongation at break of 4.6–7.9%, and tensile modulus of 1.6–2.9 GPa. They were reasonably stable up to a temperature above 400°C for the PBII and above 450°C for the composites. Structural and morphological evaluation of the composites was carried out by Fourier transform infrared spectroscopy and X-ray diffraction. Dispersion of MWCNT-ASA in the polymer matrix was investigated by field emission scanning and transmission electron microscopy.

Preparation of Electrospun Protein Nanofibers with Multiwalled Carbon Nanotubes

2006 ◽  
Vol 326-328 ◽  
pp. 1737-1740 ◽  
Author(s):  
Min Sung Kang ◽  
Seok Ho Yoon ◽  
Hyoung Joon Jin
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Silk Fibroin ◽  
Electrospun Nanofibers ◽  
Water Soluble ◽  
Wound Dressings ◽  
Multiwalled Carbon ◽  
Water Soluble Polymer ◽  
Fibrous Protein

A simple and mass producible method was developed to incorporate multiwalled carbon nanotubes (MWCNTs) into electrospun silk fibroin (Bombyx mori) nanofibers. The process consists of dispersing the acid-treated MWCNTs in an aqueous silk fibroin solution, and blending this solution with a water-soluble polymer, poly(ethylene oxide) (PEO), followed by electrospinning of the composite solution. The morphology and microstructure of the electrospun nanofibers were characterized using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The FESEM and TEM images show that the MWCNTs are embedded along the nanofibers. Aqueous-based electrospinning of silk/PEO/MWCNTs composites provides potentially useful options for the fabrication of biomaterial scaffolds, e.g. wound dressings, based on this unique fibrous protein.

scholarly journals Significantly Improved Dielectric Performance of Poly(1-butene)-Based Composite Films via Filling Polydopamine Modified Ba(Zr0.2Ti0.8)O3-Coated Multiwalled Carbon Nanotubes Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 285
Author(s):  
Lingfei Li ◽  
Qiu Sun ◽  
Xiangqun Chen ◽  
Zhaohua Jiang ◽  
Yongjun Xu
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Constant ◽  
Energy Storage ◽  
Composite Film ◽  
Multiwalled Carbon Nanotubes ◽  
Sol Gel ◽  
Composite Films ◽  
Weak Electric Field ◽  
Multiwalled Carbon ◽  
Dielectric Performance

The low dielectric constant of the nonpolar polymer poly(1-butene) (PB-1) limits its application as a diaphragm element in energy storage capacitors. In this work, Ba(Zr0.2Ti0.8)O3-coated multiwalled carbon nanotubes (BZT@MWCNTs) were first prepared by using the sol–gel hydrothermal method and then modified with polydopamine (PDA) via noncovalent polymerization. Finally, PB-1 matrix composite films filled with PDA-modified BZT@MWCNTs nanoparticles were fabricated through a solution-casting method. Results indicated that the PDA-modified BZT@MWCNTs had good dispersion and binding force in the PB-1 matrix. These characteristics improved the dielectric and energy storage performances of the films. Specifically, the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film exhibited the best dielectric performance. At 1 kHz, the dielectric constant of this film was 25.43, which was 12.7 times that of pure PB-1 films. Moreover, its dielectric loss was 0.0077. Furthermore, under the weak electric field of 210 MV·m−1, the highest energy density of the PDA-modified 10 vol% BZT@ 0.5 vol% MWCNTs/PB-1 composite film was 4.57 J·cm−3, which was over 3.5 times that of PB-1 film (≈1.3 J·cm−3 at 388 MV·m−1).

scholarly journals Surface Properties of Silica–MWCNTs/PDMS Composite Coatings Deposited on Plasma Activated Glass Supports

2021 ◽  
Vol 11 (19) ◽  
pp. 9256
Author(s):  
Michał Chodkowski ◽  
Iryna Ya. Sulym ◽  
Konrad Terpiłowski ◽  
Dariusz Sternik
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Scanning Electron Microscopy ◽  
Multiwalled Carbon Nanotubes ◽  
Composite Coatings ◽  
Thermal Analyses ◽  
Sol Gel ◽  
Visible Range ◽  
Multiwalled Carbon ◽  
Scanning Electron

In this paper, we focus on fabrication and physicochemical properties investigations of silica–multiwalled carbon nanotubes/poly(dimethylsiloxane) composite coatings deposited on the glass supports activated by cold plasma. Air or argon was used as the carrier gas in the plasma process. Multiwalled carbon nanotubes were modified with poly(dimethylsiloxane) in order to impart their hydrophobicity. The silica–multiwalled carbon nanotubes/poly(dimethylsiloxane) nanocomposite was synthesized using the sol–gel technique with acid-assisted tetraethyl orthosilicate hydrolysis. The stability and the zeta potential of the obtained suspension were evaluated. Then, the product was dried and used as a filler in another sol–gel process, which led to the coating application via the dip-coating method. The substrates were exposed to the hexamethyldisilazane vapors in order to improve their hydrophobicity. The obtained surfaces were characterized by the wettability measurements and surface free energy determination as well as optical profilometry, scanning electron microscopy, and transmittance measurements. In addition, the thermal analyses of the carbon nanotubes as well as coatings were made. It was found that rough and hydrophobic coatings were obtained with a high transmittance in the visible range. They are characterized by the water contact angle larger than 90 degrees and the transmission at the level of 95%. The X-ray diffraction studies as well as scanning electron microscopy images confirmed the chemical and structural compositions of the coatings. They are thermally stable at the temperature up to 250 °C. Moreover, the thermal analysis showed that the obtained composite material has greater thermal resistance than the pure nanotubes.

Covalent functionalization of multiwalled carbon nanotubes with super-hydrophobic property

2018 ◽  
Vol 38 (6) ◽  
pp. 537-543 ◽  
Author(s):  
Minghua Li ◽  
Zhiyuan Xu ◽  
Jinyang Chen ◽  
San-E Zhu
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Chemical Interaction ◽  
Hydrophobic Property ◽  
Covalent Functionalization ◽  
Multiwalled Carbon ◽  
Surface Contact Angle ◽  
Loading Ratio ◽  
Functionalized Mwcnts

AbstractSurface covalent functionalization of multiwalled carbon nanotubes (MWCNTs) is carried out by coupling of isocyanate-decorated MWCNTs with hydroxyl-terminated polydimethylsiloxane (HTPS), resulting in the formation of functionalized MWCNTs. Thermogravimetry analysis (TGA) of functionalized MWCNTs-1,2,3 exhibits the similar peaks in the temperature range of 200–500°C, which all correspond to the degradation of chemically grafted polyurethane on the nanotube surface. Field emission scanning electron microscopy (FE-SEM) reveals that as the polyurethane grafted onto the surface of MWCNTs loading ratio increased, the surface roughness of the MWCNTs is reduced. The chemical interaction of HTPS with isocyanate-decorated nanotube surface using the grafting-to strategy in a one-step process is confirmed by Fourier transform infrared spectroscopy (FT-IR). The surface contact angle of MWCNTs-3 with the largest content of polyurethane reached 171°, indicating that the surface covered with low surface energy polyurethane shows a super-hydrophobic property. The good dispersion of polyurethane-functionalized MWCNT-3, particularly at high content in the NR nanocomposites, is evidenced from transmission electron microscopy (TEM).

Nanocomposites Based on Multiwalled Carbon Nanotubes With Effective Young’s Modulus Dependent on Number of Layers

2014 ◽  
Author(s):  
Preeti Joshi ◽  
S. H. Upadhyay
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Multiwalled Carbon Nanotubes ◽  
Matrix Material ◽  
Tensile Modulus ◽  
Element Model ◽  
Solid Matrix ◽  
Multiwalled Carbon ◽  
Number Of Layers ◽  
Transverse Modulus

The excellent combination of high strength, stiffness, low density and aspect ratio makes carbon nanotubes ideal reinforcement for nanocomposites. The load transfer between the outer and inner layers of multiwalled carbon nanotubes (MWCNT) is one of the important factor in the reinforcement of nanocomposites. In this work, the effect of variation in number of layers of multiwalled carbon nanotubes on effective tensile, compressive and transverse modulus of composite is evaluated. A 3-D finite element model based on representative volume element, consisting of multiwalled carbon nanotube made of shell elements surrounded by solid matrix material is built. With the increase in number of layers in multiwalled carbon nanotubes, the compressive modulus of composite increases, while the tensile modulus decreases. The transverse modulus of composite is found to increase, with the increase in number of layers in MWCNT. The finite element results for composite are compared with the rule of mixtures results using formulae.

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

2020 ◽  
Vol 20 (6) ◽  
pp. 3576-3581
Author(s):  
Ruben Sarabia-Riquelme ◽  
Camila Gomez ◽  
Dali Qian ◽  
John Craddock ◽  
Matthew Weisenberger
Keyword(s):  
Carbon Nanotubes ◽  
Seebeck Coefficient ◽  
Multiwalled Carbon Nanotubes ◽  
Thermoelectric Properties ◽  
Composite Films ◽  
Spray Coating ◽  
Multiwalled Carbon ◽  
Nitrogen Doped ◽  
Mwcnt Concentration ◽  
Polyethylene Terephthalate Substrate

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.

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