Nanotube Nanocomposite Films Research Articles

Mechanical and Functional Properties of Novel Biobased Poly(decylene-2,5-furanoate)/Carbon Nanotubes Nanocomposite Films.

The present work investigates the microstructural, thermo-mechanical, and electrical properties of a promising, but still not thoroughly studied, biobased polymer, i.e., poly(decylene furanoate) (PDeF), and its performance when multi-walled carbon nanotubes (CNTs) are added. After sample preparation by solution mixing and film casting, the microstructural investigation evidences that the fracture surface becomes smoother and more homogeneous with a small fraction of CNTs, and that the production process is suitable to achieve good disentanglement and dispersion of CNTs within the matrix, although some aggregates are still observable. CNTs act as nucleating agents for PDeF crystals, as evidenced by differential scanning calorimetry, as the crystallinity degree increases from 43.2% of neat PDeF to 55.0% with a CNT content of 2 phr, while the crystallization temperature increases from 68.4 °C of PDeF to 91.7 °C of PDeF-CNT-2. A similar trend in crystallinity is confirmed by X-ray diffraction, after detailed Rietveld analysis with a three-phase model. CNTs also remarkably improve the mechanical performance of the bioderived polymer, as the elastic modulus increases up to 123% and the stress at break up to 131%. The strain at break also increases by +71% when a small amount of 0.25 phr of CNTs are added, which is probably the consequence of a more homogeneous microstructure. The long-term mechanical performance is also improved upon CNT addition, as the creep compliance decreases considerably, which was observed for both the elastic and the viscoelastic component. Finally, the films become electrically dissipative for a CNT content of 1 phr and conductive for a CNT amount of 2 phr. This study contributes to highlight the properties of bioderived furan-based polymer PDeF and evidences the potential of CNTs as a promising nanofiller for this matrix.

Improved flame-retardant properties of polydimethylsiloxane/multi-walled carbon nanotube nanocomposites

The flame-retardant properties of polydimethylsiloxane (PDMS)/oxidised multi-walled carbon nanotubes (MWCNT–COOH) nanocomposite films were dispersed using a nonionic acrylate copolymer surfactant. The nanocomposite films were prepared by spin coating and characterised using SEM, quasi-elastic cold-neutron scattering, TGA–FTIR, cone calorimetry, and LOI. The PDMS/surfactant/MWCNT–COOH (PSM) nanocomposite displayed superior flame-retardant performance compared to materials containing only surfactant or MWCNT–COOH. The peak heat release rate, the peak smoke production rate, total smoke release rate, carbon monoxide, and carbon dioxide production from PSM were 42, 47, 18, 28, and 47% less than the PDMS control. The LOI results for PSM exhibited a value of 32% with respect to 25% for the PDMS. PSM suppresses the smoke emission and inhibits penetration of the air reacting with the gas volatiles of the material. These new nanocomposites provide a valuable improvement in flame-retardant capabilities by physical barrier effect compared to other PDMS polymer materials.

Effect of nature of polymer as a binder in making photoanode layer and its influence on the efficiency of dye-sensitized solar cells

A simple method has been developed for the preparation of photoanode paste from hydrothermally synthesized nanocomposite, using different nature of polymers viz., synthetic: poly(vinyl alcohol) and polystyrene (PS) and natural: casein and sodium alginate (NaAlg) as binders. The titanium dioxide (TiO2)/multi-walled carbon nanotube (MWCNT) nanocomposite powder and film were characterized for analysis of their structure, crystallinity and morphology by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. Dye-sensitized solar cells (DSSCs) were fabricated using TiO2/MWCNT composite paste made with different binders as photoanode, N719 dye, platinum as photocathode and Idolyte HI-30. The observed results of photocurrent density–voltage characteristics and electrochemical impedance spectroscopy suggested that the nature of the binder used in making photoanode film showed significant influence on the overall characteristics of DSSCs. Among the cells fabricated, the DSSC fabricated using TiO2/MWCNT-PS binder showed highest power conversion efficiency of 3.03%.

Development of reinforced aldehyde-modified kappa-carrageenan/gelatin film by incorporation of halloysite nanotubes for biomedical applications

Recently, with the progression in tissue engineering, the importance of biocompatible nanocomposite film with suitable properties for potential applications in the biomedical area has been more developed. In this work, nanocomposite films of aldehyde-modified Carrageenan/Gelatin/halloysite nanotubes (AD-Carr/Gel/HNTs) nanocomposite films were successfully fabricated by the solution casting process. Halloysite nanotubes (HNTs) with different concentrations (0.5, 1.0, and 1.5 wt%) loaded into the aldehyde-modified Carrageenan/Gelatin (AD-Carr/Gel). Meanwhile, the developed AD-Carr/Gel/HNTs nanocomposite films were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), mechanical property, water adsorption as well as in vitro degradation. The feasibility and capability of the nanocomposite films were further evaluated by hemocompatibility study, which showed that these nanocomposite films are hemocompatible. Besides, MTT assay revealed that the nanocomposite films are non-toxic, presenting the films as a good candidate to be used for tissue engineering purposes.

Synthesis and characterization of platinum multi-walled carbon nanotubes nanocomposite film electrode

Carbon nanotubes (CNTs) were synthesized by a bimetallic (Fe–Co/CaCO3) catalytic chemical vapour deposition (CCVD) method. The synthesized CNTs were purified with acid to remove the catalyst impurities to enhance the deposition of platinum (Pt) onto the CNTs surface. Platinum multiwall (Pt-MWCNTs) nanocomposites were produced by a wet impregnation technique dispersed in Texanol and Acrylic resins to form a paste. The paste was screen printed on an FTO glass substrate. Surface morphology, microstructure, chemical composition, crystallographic phase, surface area and electrical performance of the Pt-MWCNTs nanocomposites were measured by HRSEM, HRTEM, EDS, XPS and XRD. The electrical conductivity of the electrode produced was found to be 4.927 S m−1. The results showed that the prepared nanocomposites will be a good electrode material in solar cell applications.

Characterization of PVC/MWCNTs Nanocomposite: Solvent Blend

Abstract Polyvinyl Vinyl Chloride (PVC) multiwall carbon nanotubes (MWCNTs) nanocomposite flexible films were prepared using the solvent blend technique. Chloroform (CHCl3) and tetrahydrofuran ((CH2)4O) were used as solvents for MWCNTs and PVC, respectively. The effect of the solvents’ blend on electrical, optical and thermal properties of PVC/MWCNTs were investigated. The results of the Raman spectrum showed that all the characteristic bands of PVC polymer have a slight shift due to addition of MWCNTs. Electrical results showed that the nanocomposite samples with chloroform volume ratios of 10% and 25% had nearly the same conductivity. This is attributed to the formation of the MWCNTs network, which assisted in electrical conductivity. The I-V hysteresis curve decreases as the temperature increases and as it approaches the glass transition temperature. The non-isothermal kinetics analysis for PVC and PVC/MWCNTs were investigated by Thermogravimetry Analysis (TGA) using the model-free kinetic method. The non-isothermal measurements were carried out at five heating rates of 5 to 40∘C/min. The results show that the main decomposition process has constant apparent activation energies for all samples. The use of the bi-solvent method has improved the dispersion of untreated MWCNTs, and this has been reflected on the stability of both electrical and thermal properties.

Correction to: Preparation and characterisation of poly(vinyl) alcohol (PVA)/starch (ST)/halloysite nanotube (HNT) nanocomposite films as renewable materials

Correction to: Preparation and characterisation of poly(vinyl) alcohol (PVA)/starch (ST)/halloysite nanotube (HNT) nanocomposite films as renewable materials

Enhanced Thermoelectric Performance of Conjugated Polymer/CNT Nanocomposites by Modulating the Potential Barrier Difference between Conjugated Polymer and CNT

Small-bundled single-walled carbon nanotube (SSWCNT) nanocomposite films with two different conjugated polymers were facilely prepared by using a micronizing mill. The influence of the difference i...

Third order nonlinear optical properties of β enhanced PVDF based nanocomposite thin films

PVDF based nanocomposite thin films have received great interest in energy harvesting, ferroelectric, pyroelectric and dielectric applications. In this novel study, we have exploited the electroactive β-phase (polar) formation in polyvinylidine fluoride–halloysite nanotube (PVDF–HNT) nanocomposite thin films fabricated by the spin coating technique for nonlinear optical applications. It was demonstrated that HNTs of different volume percentage loadings in the PVDF matrix were able to effectively nucleate PVDF in β (TTTT-all trans) conformation using X-ray diffraction and Infrared spectroscopy techniques. Closed aperture Z-scan measurements were performed for all the thin film samples with a CW laser as an excitation source at a wavelength of 632.8 nm. We observed a sign change in the nonlinear refractive index for PVDF. Nonlinear refractive index has a negative sign for pristine PVDF and a positive sign for HNT incorporated PVDF thin films. This anomalous behavior of change in the nonlinear refraction of PVDF is explained in our present work.

Biodegradable and Water Resistant Poly(vinyl) Alcohol (PVA)/Starch (ST)/Glycerol (GL)/Halloysite Nanotube (HNT) Nanocomposite Films for Sustainable Food Packaging

As a novel biodegradable material, poly (vinyl) alcohol (PVA)/starch (ST)/ glycerol (GL)/ halloysite nanotube (HNT) nanocomposite films were prepared by solution casting at the HNT contents of 0.25, 0.5, 1, 3 and 5 wt%. Water absorption capacity and water solubility of nanocomposite films were decreased remarkably by 44.24 and 48.05%, respectively, with increasing the HNT content from 0 to 5 wt% when compared with those of biopolymer matrices. Moreover, the water contact angle of nanocomposite films increased by 21.36o with the incorporation of HNTs. The presence of HNTs appeared to reduce the overall migration rates for PVA/ST/GL/HNT nanocomposite films when interacting with either hydrophilic or lipophilic food simulants. However, the migration rates of HNTs alone were enhanced with increasing the HNT contents in hydrophilic, lipophilic and acidic food simulants. On the other hand, the biodegradation rate and light transmittance of nanocomposite films were reduced linearly by 18.56 and 26.90% with increasing the HNT content from 0 to 5 wt%. Overall, novel PVA/ST/GL/HNT nanocomposite films in this study offer highly competitive material with excellent water resistance, good biodegradability and acceptable transparency to be potentially used for sustainable food packaging particularly targeting lipophilic and acidic foodstuffs.

Development of bio-hybrid piezoresistive nanocomposites using silk-elastin protein copolymers

Recombinant silk-elastin-like protein (SELP)/carbon nanotubes (CNTs) nanocomposite films with different amounts of CNTs (1, 3 and 6 wt%) were prepared by solvent casting. The produced films were stabilized by exposure to methanol that induces an increase of the β-structure content. The CNTs were homogeneously distributed into the SELP matrix and did not induce significant alterations into its chemical structure. The incorporation of CNTs also increased the thermal stability of the films. Further, the incorporation of 1 wt% of CNTs greatly improved the mechanical properties of the SELP matrix leading to a 6-fold increase in strain-to-failure and to increase the ultimate tensile strength with minor differences in modulus of elasticity. The nanocomposites exhibited a good linearity between deformation and electrical resistance variation with electrical conductivity increasing with the nanofiller content up to 0.8 S m−1. Finally, the produced nanocomposites were non-cytotoxic indicating their suitability for biomedical applications.

PANI/MWCNT based humidity sensor

Polyaniline Multi wall Carbon nanotube (PANI/MWCNTs) nanocomposite thin films have been prepared by Plasma jet polymerization at low frequency on glass substrate with preliminary deposited aluminum electrodes to form Al/PANI-MWCNT/Al surface-type capacitive humidity sensors, the gap between the electrodes about 50 μm and the MWCNTs weight concentration varied between 0, 1, 2, 3, 4%. The diameter of the MWCNTs was in the range of 8-15 nm and the length 10-55 μm. The capacitance-humidity relationships of the sensors were investigated at humidity levels from 35 to 90% RH. The electrical properties showed that the capacity increased with increasing relative humidity, and that the sensitivity of the sensor increases with the increase of the additive (MWCNTs); while each of the response time and the recovery time increasing with concentration. The change in MWCNTs concentration leads to a change in the energy gap as well as the initial capacity. The capacitance increases linearly with the relative humidity at MWCNTs concentration of 3% for thus the possibility of manufacturing humidity sensor with good specifications at this concentration.

Structure and optical properties of PANI/MWCNTs nanocomposites thin films prepared by plasma jet polymerization

Polyaniline Multi walled Carbon nanotubes (PANI/MWCNTs) nanocomposite thin films have been prepared by non-equilibrium atmospheric pressure plasma jet on glass substrate with different weight percentage of MWCNTs 1, 2, 3, 4%. The diameter of the MWCNTs was in the range of 8-55 nm and length - - 55 55 μm. the nanocomposite thin films were characterized by UV-VIS, XRD, FTIR, and SEM. The optical studies show that the energy band gap of PANI/MWCNTs nanocomposites thin films will be different according to the MWCNTs polyaniline concentration. The XRD pattern indicates that the synthesized PANI/MWCNTs nanocomposite is amorphous. FTIR reveals the presence of MWCNTs nanoparticle embedded into polyaniline. SEM surface images show that the MWCNTs homogenously inside the polyaniline house. It can be concluded that the nanocomposite can be prepared PANI/MWCNTs thin films by plasma jet polymerization and control the optical energy band gap irregulars by controlling the MWCNTs weight concentration.

Chitosan/MWCNTs composite as bone substitute: Physical, mechanical, bioactivity, and biodegradation evaluation

In the present research, via the solvent casting method, Chitosan(CS)/multiwalled carbon nanotubes (MWCNTs) nanocomposite films were prepared through the use of four different percentages (1, 1.5, 2, and 2.5 wt%) of CS as polymer matrix and two percentages (0.5 and 1 wt%) of MWCNTs as ceramic reinforcement. Based on the results of TGA, it was shown that the addition of MWCNTs augmented the thermal stability of CS film. The results of XRD showed that MWCNTs induced the crystallization of chitosan film and FTIR analysis demonstrated the formation of CS/MWCNTs composite film. According to the results of tensile tests, the highest strength belonged to 2.5 wt% CS/0.5 wt% MWCNTs nanocomposite film which was increased by 176% (from 18.26 to 50.46 MPa) in comparison to tensile strength of 2.5 wt% CS film and the Young's modulus of CS/MWCNTs film increased by 195% (from 406 to 1,197 MPa) in comparison to the Young's modulus of CS film. The best film with 2.5 wt% CS/0.5 wt % MWCNTs was selected as an optimum sample for other experiments. Contact angle analysis indicated that with the addition of MWCNTs, the contact angle of CS films decreased. The results of bioactivity test showed that adding 0.5 wt% MWCNTs to CS film improved the bioactivity of CS film. Based on the biodegradability evaluation, the addition of MWCNTs to CS film reduced the degradation rate of CS film. The research illustrated the potentials of CS/MWCNTs in bone substitute. POLYM. COMPOS., 40:E1622–E1632, 2019. © 2018 Society of Plastics Engineers

Comparing the performance of electrospun and cast nanocomposite film of polyamide-6 reinforced with multi-wall carbon nanotubes

This study aims at fabrication and characterization of two different structures of electrically conductive polyamide 6/multi-wall carbon nanotube nanocomposite films at different multi-wall carbon nanotube concentrations including electrospun nanofibrous and cast films. Morphology, embedded multi-wall carbon nanotubes into nanofiber, thermal behavior, electrical conductivity and wettability of films were characterized. Scanning electron microscopy images depicted that the nanofiber diameter decreased with increased nanofillers. Enhancement of crystallinity, electrical and tensile properties, and simultaneously achieving a low percolation threshold confirmed good nanotube dispersion by employing a polymeric emulsifier, polyvinylpyrrolidone. The electrospun film crystalline content increased 18.5% and the cast ones increased 46.8% at 7 wt.% multi-wall carbon nanotubes loading. The electrospun and cast membrane electrical conductivity increased by 10 and 12 orders of magnitude. These results demonstrated higher values compared to previously reported data for polyamide 6/multi-wall carbon nanotube nanocomposites. The electrospun film Young’s modulus increased 93% and that of casted one increased 267%, due to the increased crystallinity after adding carbon nanotubes into the films.

Effect of Surfactant Type and Sonication Energy on the Electrical Conductivity Properties of Nanocellulose-CNT Nanocomposite Films.

We present a detailed study on the influence of sonication energy and surfactant type on the electrical conductivity of nanocellulose-carbon nanotube (NFC-CNT) nanocomposite films. The study was made using a minimum amount of processing steps, chemicals and materials, to optimize the conductivity properties of free-standing flexible nanocomposite films. In general, the NFC-CNT film preparation process is sensitive concerning the dispersing phase of CNTs into a solution with NFC. In our study, we used sonication to carry out the dispersing phase of processing in the presence of surfactant. In the final phase, the films were prepared from the dispersion using centrifugal cast molding. The solid films were analyzed regarding their electrical conductivity using a four-probe measuring technique. We also characterized how conductivity properties were enhanced when surfactant was removed from nanocomposite films; to our knowledge this has not been reported previously. The results of our study indicated that the optimization of the surfactant type clearly affected the formation of freestanding films. The effect of sonication energy was significant in terms of conductivity. Using a relatively low 16 wt. % concentration of multiwall carbon nanotubes we achieved the highest conductivity value of 8.4 S/cm for nanocellulose-CNT films ever published in the current literature. This was achieved by optimizing the surfactant type and sonication energy per dry mass. Additionally, to further increase the conductivity, we defined a preparation step to remove the used surfactant from the final nanocomposite structure.

Influence of gamma radiation on optical properties of Halloysite nanotubes incorporated polycarbonate nanocomposites

ABSTRACTIn the current research investigation, polycarbonate/hallyosite nanotubes (PC/HNTs) nanocomposite (NC) films have been successfully fabricated by solution intercalation technique using ultrasound energy in facile way which helps complete exfoliation of the HNTs in the matrix. The effect of Gamma irradiation-induced modifications of PC/HNTs NC have been studied in the dose range 200–500 kGy, irradiated with Co60 source. The NC films have been evaluated by UV–visible spectroscopy, Fourier Transform Infrared spectroscopy, X-ray diffraction and scanning electron microscopic techniques in order to probe the effect of gamma radiation on the structural behaviors. The obtained results have been indicated that as the Gamma irradiation dosage increases from 200 to 500 kGy, phenolic group forms through scissoring of ester link of PC, which may cause PC to degrade and lose their property. At lower dosage (200 kGy), the effect is less and at higher dosage (500 kGy), the effect is significant and at 300 and 400 kGy, the effect is moderate and NC films retained their properties. The irradiation effect is most significant and effective at the higher dosage range. UV–visible spectroscopy shows a noticeable reduction in the energy band gap due to gamma irradiation.

Morphological, mechanical and AC electrical conductivity of polyvinyl alcohol loaded with single walled carbon nanotubes

Two series of polyvinyl alcohol/single walled carbon nanotubes (PVA/SWCNTs) nanocomposite films were prepared using sonicator in double distilled water solution to obtain a well dispersion of SWCNTs in polyvinyl alcohol as a host material using casting techniques. The mechanical properties are significantly improved and enhanced as compared to the pure PVA film after adding the SWCNTs. Young's modulus and tensile strength are increased after adding SWCNTs. The prepared films are studied by TEM and AC conductivity measurements. The TEM demonstrated that SWCNTs is well distributed in PVA matrices with some broken of SWCNTs revealing that SWCNTs broke aside as opposed to being pulled out from fracture surface suggest an interfacial bonding with some wrapped around PVA. The maximum values of AC conductivity are observed at the higher frequency. Both dielectric constant (ε') and dielectric loss (ε") are decreased with an increase of the frequency related to the direction of dipoles in PVA matrices orient toward applied field. Decrease trend at maximum frequency has seemed stable due to difficult of dipoles rotation. The values of dielectric parameters are increased gradually with the increase in both the temperature and the concentration of SWCNTs.

A High-Stability QCM Humidity Sensor Coated With Nanodiamond/Multiwalled Carbon Nanotubes Nanocomposite

In this paper, a high-stability QCM humidity sensor coated with nanodiamond (ND)/multiwalled carbon nanotubes (MWCNTs) nanocomposite film was purposed based on good dispersion of MWCNTs in ND solution. The experimental results demonstrated that the sensor not only had a relative high frequency shift with humidity change, but also maintained a high quality (Q) factor compared with that of pure ND film coated sensor. In high humidity, the Q factor of ND/MWCNTs coated sensor is about four times larger than that of pure ND coated sensor, and can retain negligible change as long as several months. The possible reason was analyzed and discussed. Moreover, the sensor exhibited low hysteresis, fast response/recovery time, and good repeatability.

Influence of the incorporation of small conjugated molecules on the thermoelectric properties of carbon nanotubes

Abstract Small-bundled single-walled carbon nanotube (SSWCNT) nanocomposite films made with various small molecules were facilely fabricated using the micronizing mill process. Finely dispersed small molecules in the SSWCNT film can effectively reduce the in-plane thermal conductivity of the nanocomposite due to π-π interactions. Furthermore, the micronizing mill process ensures the uniform distribution of the small molecules and the SSWCNTs in the nanocomposite film without any damage or deformation of the SSWCNT structure. Moreover, the influence of the shape of the small molecules on the thermoelectric properties of SSWCNT nanocomposite was systematically investigated. The thermoelectric properties of the pyrene/SSWCNT nanocomposite were found to have been greatly improved by the planar pyrene molecules with a slightly increased electrical conductivity of 978.6 S cm−1 and a significantly decreased in-plane thermal conductivity of 13.5 W m-1 K-2. The evaluated ZT value of the pyrene/SSWCNT nanocomposite was 4.4 × 10−3 and is about 20 times higher than that of the pristine SSWCNT nanocomposite. A planar-type thermoelectric generator (TEG) consisting of 20 legs was also fabricated using this pyrene/SSWCNT nanocomposite. The TEG showed an open circuit voltage of 20 mV and a short circuit current of 350 μA, resulting in a maximum output power of 1.5 μW at ΔT = 20 °C.