Aspect Ratio Of Carbon Nanotubes Research Articles

A computational model for characterizing electrical properties of flexible polymer composite filled with CNT/GNP nanoparticles

Ultrasensitive flexible sensors with a high sensitivity in a broad pressure range are required for various applications in flexible electronics era. Hybrid nanocomposites reinforced by carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) have shown improvements in cost-effectiveness and electrical properties. Simulating the hybrid nanocomposites is of vital significance since it offers an insight into the functional and electrical performance of flexible sensors. In this paper, the structural evolution of CNT and GNP nanocomposites in response to mechanical deformation is theoretically modeled to clarify the synergy mechanism of two nanofillers. The influence of the microstructure parameters including the aspect ratio (AR) and volume ratio of CNT and GNP on the conductivity and sensitivity of the flexible composites are comprehensively analyzed and discussed. Analytical simulation and experimental results show that the conductivity of the mixed filler system fails to outperform any individual system, but shows superiority regarding to the piezoresistive sensitivity. Besides, the Poisson's ratio of the polymer is innovatively introduced to characterize the elastic deformation of the nanocomposites. It was found that the Poisson's ratio of the polymer had the negative correlation with the sensitivity of the CNT/GNP nanocomposite. This work provides considerable guidance for the design and manufacture of flexible piezoresistive sensors.

Interphase elastic properties of carbon nanotube-epoxy composites and their application in multiscale analysis

A multiscale framework was developed to predict the elastic properties of carbon nanotube (CNT)–epoxy composites. The interfacial vacuum layer between the CNTs and epoxy was equivalent to transversely isotropic elastomer. The elastic constants were calibrated based on the interaction energy density in the molecular dynamics simulations; the results exhibited significant differences between these constants. The out-of-plane shear modulus (46.64 MPa) is four orders of magnitude smaller than the in-plane Young’s modulus (362.68 GPa). Subsequently, representative volume elements containing transversely isotropic interphases were developed using the finite element method and analysed comparatively to models without interphases. The results indicated that their difference in the Young’s modulus enhancement ratio was sensitive to the CNT aspect ratio. The enhancement ratio of the model containing the interphase was lower when the CNT aspect ratio exceeded a certain value. This difference increased with increasing CNT aspect ratio and was significant at high CNT aspect ratios (7.35 % when the aspect ratio reached 30). In addition, shear-lag analysis indicated that the interphase increased the interfacial load transfer length. This framework provides efficient interfacial simulations, giving a more accurate prediction of bulk elastic properties and can be extended to a wider range of nanocomposites.

Energy dissipation of CFRP composites coated by wavy CNT with focus on the CNT maximum reachable volume fraction

Dynamic moduli and energy dissipation capability of polymer hybrid nanocomposite reinforced with carbon fiber (CF) coated by carbon nanotube (CNT) which makes a fuzzy fiber nanocomposite (FFNC) are estimated through a micromechanical model. An analytical expression is derived to extract the damping properties in the frequency domain. Then, a separate phase known as interphase whose properties vary gradually is taken into account to model the CNT/polymer interactions. The CNT waviness and random orientation are also included. Acceptable agreements in comparison with the molecular dynamics simulations and experiments prove the accuracy of the proposed model. Moreover, the maximum reachable volume fraction of CNTs is studied considering the radius of gyration of polymer chain, the CNT aspect ratio (CNTAR), radius, and waviness amplitude. The effects of the CNT inter-tube distance (CNTID), waviness, CNTAR, and the loading frequency are examined on the energy dissipation and storage capability, and hysteresis loop of FFNC. It is found that the FFNC effective dynamic moduli enhance by increasing the CNTAR, while the CNTAR becomes less influential as the CNTID increases. Furthermore, as the frequency increases, the area of the hysteresis loop is decreased. Whereas the hysteresis loop is converted to a straight line beyond the frequency of about 1e17 Hz.

Influence of the aspect ratio of nitrogen-doped carbon nanotubes on their piezoelectric properties

Recent studies have shown that nitrogen doping of carbon nanotubes (CNTs) can lead to the formation of piezoelectric properties in them, not characteristic of pure CNTs. In this work, nitrogen-doped CNTs were grown by plasma-enhanced chemical vapor deposition and the effect of the aspect ratio of the nanotube length to its diameter on its piezoelectric coefficient [Formula: see text] was shown. It was observed that as the aspect ratio of the nanotube increased from 7 to 21, the value of [Formula: see text] increased linearly from 7.3 to 10.7 pm/V. This dependence is presumably due to an increase in curvature-induced polarization because of an increase in the curvature and the number of bamboo-like “bridges” in the nanotube cavity formed as a result of the incorporation of pyrrole-like nitrogen into the nanotube structure. The obtained results can be used in the development of promising elements of nanopiezotronics (nanogenerators, memory elements, and strain sensors).

(Invited) All-Carbon Nanotube Photovoltaic Device Employing Energy Hierarchy

The use of an energy funnel or hierarchy to efficiently transfer photoexcitations is not new. In photosynthetic systems, whether in plants, algae, or photosynthetic bacteria, to achieve high efficiency, special light-harvesting protein complexes convert sunlight to excitons. High efficiency is achieved by temporarily storing excitons in these complexes before shuttling them to the reaction center where the conversion to usable energy takes place. For added efficiency, photosynthetic systems have adopted an energy hierarchy that funnels excitations from the light-harvesting complexes to the reaction center.The use of an energy funnel to increase the efficiency of photovoltaic devices, however, has not been widely adopted, due in part to limited materials compatibility and energy landscape. An energy funnel can absorb over a broad solar spectrum while minimizing the volume of material needed to construct a device, which can reduce the dark leakage current. Carbon nanotubes (CNTs) provide an ideal system to explore this new feature since a single material system can provide a wide range of energy levels. Depending on the diameter, excitonic levels in CNTs span from the visible to near-infrared spectrum. Furthermore, the device design can take advantage of the high aspect ratio of CNTs, to efficiently transport both free carriers and excitons along the nanotube.Here, we describe our efforts to develop photovoltaic p-n diodes using energy hierarchy. We use a network of CNTs in a p-n junction configuration where the transport is mostly along the CNTs. To form the p-n junction, we use buried split gates that are biased independently to form the p- and n-doped regions. The use of split gates is an extension of our earlier studies on single CNT p-n diodes.We use different chirality CNTs to implement the energy hierarchy. Specifically, the network is structured to funnel excitons by placing larger bandgap semiconducting nanotubes on top of smaller bandgap CNTs. We discuss features that show enhanced exciton to photocurrent generation in these devices compared to devices without the energy hierarchy.

Pristine carbon nanotubes are efficient absorbers at radio frequencies

Radio frequency ablation and microwave hyperthermia are powerful tools for destroying dysfunctional biological tissues. However, wireless application of these techniques is hindered by their inability to focus the electromagnetic energy to small targets. The use of locally injected radio frequency- or microwave-absorbing nanomaterials can help to overcome this challenge by confining heat production to the injected region. Previous theoretical work suggests that high-aspect-ratio conducting nanomaterials, such as carbon nanotubes, offer powerful radio frequency and microwave absorption. While carbon nanotubes have been demonstrated as radiothermal agents, common solubilization methods may reduce their absorption efficiency, yielding undesirable nonspecific heating in the biological tissue background. In this manuscript, we hypothesize that pristine carbon nanotubes can act as efficient absorbers at radio frequencies, thus providing differential heating over the tissue background. Specifically, we use a sonication-free preparation technique to preserve both the high aspect ratio and local concentration of pristine carbon nanotubes. We validate the differential heating of these samples by 4.5-fold at 2 GHz compared to the heating of saline at a physiological concentration using infrared thermography. In addition, we successfully achieved local heating of pristine carbon nanotubes within a three-dimensional biological tissue phantom. Numerical simulations further aid in producing a temperature map within the phantom and confirming localized heating. Due to their significant differential and local heating, we believe that pristine carbon nanotubes may facilitate region-specific radio frequency ablation and microwave hyperthermia while keeping nonspecific heating to a low level in the normal tissue background.

Influence of carbon nanotubes on properties of cement mortars subjected to alkali-silica reaction

This research investigates the impact of carbon nanotubes (CNTs) on the expansion, mechanical properties, and microstructure of cement mortar subjected to alkali-silica reaction (ASR). A total of eight compositions were cast to investigate the influence of CNT surface condition, concentration and aspect ratio, and ultrasonication energy. Two types of CNTs were used as reinforcement: pristine CNTs with an aspect ratio of 800 (Type I) and COOH-functionalized CNTs with an aspect ratio of 2500 (Type II). CNTs were incorporated at concentrations of 0.1c-wt.% and 0.3c-wt.%. The results indicated that certain combinations of mix proportions could significantly mitigate the ASR-induced damages in the mortar bar test (ASTM C1260). Specimens reinforced with 0.1c-wt.% of Type I CNTs exhibited the highest resistance to alkali-silica reaction. While specimens reinforced with 0.3c-wt.% of Type II CNTs had marginal improvements. More specifically, specimens reinforced with 0.1c-wt.% of Type I CNTs reduced the 14-day ASR expansion by 73% against control, and increased the 28-day compressive strength, flexural strength, static and dynamic elastic moduli by 22%, 36%, 54%, and 22%, respectively. Finally, scanning electron microscopy and X-ray energy-dispersive spectroscopy revealed that CNTs resist ASR with three main chemo-mechanical mechanisms: 1) restrain crack propagation, 2) refine the pore structure of the composite, and 3) reduce the alkalinity of the pore solution by altering the ASR gel compositions.

Modeling the synergistic electrical percolation effect of carbon nanotube/graphene/polymer composites

Electrical percolation behavior is one major concern for conductive polymer composites (CPCs). Two types of conductive fillers such as one-dimensional (1D) carbon nanotubes (CNTs) and two-dimensional (2D) graphene nanosheets are often simultaneously incorporated into one polymer to yield a synergistic effect in improving electrical percolation behavior but proper analytical models are still lacking for clearly clarifying the synergistic percolation effects of CNT/graphene/polymer composites. In this work, an analytical model based on excluded-volume theory is developed to determine the synergistic percolation threshold of ternary CNT/graphene/polymer composites. Subsequently, parametric studies are performed to examine the effects of the aspect ratio of CNTs and graphene and the relative content ratio of CNTs to graphene on the synergistic percolation threshold of the ternary CNT/graphene/polymer composites. It is suggested that both filler aspect ratios and relative content ratio of CNTs to graphene should be combinedly considered to achieve the strongest percolation synergism. Furthermore, comparisons between modeling predictions and existing experimental data are made to demonstrate the validity of the developed model. This work provides a theoretical basis for understanding the synergistic percolation effect of two types of fillers such as CNTs and graphene nanosheets in CPCs.

Study on the theoretical calculation method for the effective thermal conductivity of carbon nanotube composite molten salt for solar energy application

Carbonate salt is a potential heat storage material for solar thermal power. Aimed at calculating the effective thermal conductivity of Li 2 CO 3 -K 2 CO 3 eutectic doped with carbon nanotube (CNT), a theoretical calculation method based on the three-dimensional random curl structure model was developed. Meanwhile, for the purpose of method verification, CNT composite molten salt was prepared by high-energy ball grinding method. The curl degree of carbon nanotube was determined by image identification technique. The effective thermal conductivity of the composite molten salt was measured to validate the calculation model. The comparison showed that, for well-mixed CNT composite molten salt, the error of the theoretical calculation model was less than 8.5%, which indicated that this calculation model can be used to calculate the effective thermal conductivity of CNT composite molten salt. Moreover, the influence of key factors such as the curl degree and aspect ratio of CNT on the effective thermal conductivity of composite molten salt were revealed. The results included that, first, the effective thermal conductivity ( λ eff ) of composite molten salt decreased with increasing CNT curl degree. Second, increasing CNT aspect ratio to 175 could improve λ eff of composite molten salt. Third, the increase of CNT thermal conductivity was the key factor to the improvement of λ eff of composite molten salt. Fourth, λ eff of the composite molten salt could be significantly increased when the order of magnitude of the interfacial thermal resistance (m 2 ·K·W −1 ) was reduced to 10 −7 . • A calculation model on λ of CNT enhanced molten salt for heat storage is given. • Curl phenomenon of carbon nanotube is quantified via image identification. • 3-D random curl structure physical model is established. • Carbon nanotube enhanced salt is prepared by ball milling method and tested. • Effective thermal conductivity calculation is validated with experiments.

Modeling of the piezoresistive behavior of carbon nanotube/polymer composites during stress relaxation

AbstractThe resistance change of carbon nanotube (CNT)/polymer composites during stress relaxation depended strongly on the CNT concentration and aspect ratio. At low concentration, the resistance of the composites increased regardless of aspect ratio of CNTs as relaxation progressed, while the relaxation modulus accordingly decreased. This trend changed with CNT concentration. To investigate the mechanism, a new resistor model was developed based on the number of contacts between CNTs within tunneling distance of each other. Simulations revealed that when the number of contacts between CNTs is insufficient to form multiple conducting pathways, the increased tunneling resistance has more influence on the overall resistance, leading to the increased resistance. Finally, the proposed resistor model was used to qualitatively explain the resistance change of the composites at different CNT concentration and aspect ratios during tensile test, demonstrating its validity.

Vibration reduction of FG-CNTR piezoelectric laminated composite cantilever plate under aerodynamic load using full-dimensional state observer

A robust control method is developed to suppress the vibrations of the functionally graded carbon nanotube-reinforced (FG-CNTR) piezoelectric laminated composite cantilever plate subjected to the aerodynamic force and thermal environment. The distributions of the carbon nanotubes (CNTs) in the entire plate thickness are classified as the functionally graded (FG) or uniform distributions (UD). The effective material properties are obtained using the rule of mixtures. The classic laminated composite plate theory and Hamilton principle are used to establish the governing equations of motion for the FG-CNTR laminated composite cantilever plate under combined the aerodynamic force and thermal environment. Galerkin method is used to obtain a two-degree-of-freedom ordinary differential control equation. To actively suppress the vibration, the piezoelectric patches are used as the actuators and sensors which are attached to the upper and lower surfaces of the FG-CNTR laminated composite cantilever plate. A full-dimensional state observer is introduced to design the robust controller. To verify the efficiency of the control strategy, a comparison between the robust controller and velocity feedback controller (VFC) indicates that the robust controller has better control efficiency than the VFC. The effects of the CNT distribution, CNT volume fraction, temperature and aspect ratio on the dynamic behaviors of the laminated composite plates are studied. The effectiveness and accuracy of the proposed robust controller are verified through numerical simulations under different cases.

Ultrasensitive wearable sensor with novel hybrid structures of silver nanowires and carbon nanotubes in fluoroelastomer: Multi-directional sensing for human health monitoring and stretchable electronics

Today, wearable sensors are being developed for personalized human health monitoring for physical motion detection and physiological signal detection, and well-being. These wearable devices need to be extremely flexible, lightweight, and stretchable to be compatible with the contours of the human body, and mechanically and dynamically stable. Their functionality can be assured by simultaneously increasing conductivity, stretchability, and sensitivity for accurate and fast response. The challenge in fabricating stretchable sensors with these functionalities is embracing current wearable fashion. In this work, for the first time, a new 3D hybrid nanonetwork structures of high aspect ratio silver nanowires (AgNW) and carbon nanotubes (CNT) in fluoroelastomer FKM are developed. An optimized solution mixing (SM) and layer by layer (LBL) assembly technique, and LBL drop-coating process are employed to establish the hierarchical and shell-like nanostructures. The sensor films are ultra-thin and show high conductivity up to 2 × 105 S. m−1, high stretchability of up to 300%, and a maximum sensitivity (gage factor) of up to 2.5 × 107. The multifunctional sensor with hybrid nanonetwork shows high performance in various wearable electronic applications including human motion detection and stretchable light-emitting diode (LED) circuits. These ultra-sensitive materials show capability for multidirectional sensing by special configurations for each human body part movement, and small movements for human heartbeat monitoring.

Effect of aspect ratio and bulk density of carbon nanotube on the electrical conductivity of polycarbonate/multi‐walled carbon nanotube nanocomposites

AbstractThis study investigated the electrical conductivity of PC/multi‐walled carbon nanotube (MWCNT) nanocomposites prepared by both compression and injection molding using three different MWCNTs. Among the three MWCNTs used, two of which have similarly low‐aspect ratio (AR) (60) but different bulk density (BD) (35 and 19 kg/m3). The third MWCNT has highest AR (150) and lowest BD (11 kg/m3) among the three MWCNTs. Our findings showed that CNTs having the lowest BD and the highest AR does not always produce the best dispersion quality and highest electrical conductivity, which is contradictory to existing studies. Among three MWCNTs, the MWCNT with lower AR (60) and a BD at the mid value (19 kg/m3) exhibited the highest electrical conductivity in injection‐molded samples. This MWCNT also exhibited the highest electrical conductivity in compression‐molded samples for MWCNT content above 2 wt%. This MWCNT provided better dispersion state than MWCNT with the highest AR (150) and lowest BD (11 kg/m3). We found that BD and AR have correlative effects in the individualization and dispersion of MWCNTs from its primary agglomerates. Lower BD can improve the ease of agglomerate disintegration during extrusion while a high‐AR beyond an optimal value can entangle and coil the MWCNTs, which can actually worsen the dispersion quality of the nanotubes.

Simulation of mechanical response of carbon nanotube yarns under uniaxial tensile loading

Carbon nanotube (CNT) yarns (CNTYs) are microscopic assemblies of carbon nanotubes in the form of continuous fibers that have significant technological applications. Their applications as individual fibers or embedded in polymer composites demand tensile load bearing, but the mechanical response of CNTYs is yet not well understood. A sequential, three-step, multiscale finite element (FE) modeling approach is proposed to predict the stress-strain response of CNTYs under uniaxial tensile loading. The modeling approach is based on experimental observations, which motivates an idealized concept of the hierarchical structure of CNTYs discretized into three hierarchical levels: (i) nanoscale model of bundles comprising CNTs, (ii) mesoscale model of CNT fibrillars formed by bundles, and (iii) microscale model of the CNTYs comprising twisted CNT fibrillars. The results from each level feed the simulation of the upper level. The inherent randomness in the plexiform structure of CNTYs is addressed through the Monte Carlo method, and the effect of porosity and twist level are also included for the first time in modeling the CNTY. The simulations predict that the elastic modulus of the bundle is fairly independent of its diameter but the yield stress and strength decrease with increasing bundle diameter. The aspect ratio of the individual CNTs comprising the bundles is also shown to be a key factor determining the CNTY strength. The simulation results show that considering an orthotropic response at the microscale level provides stress-strain curves that match the experimental results. This model of the stress-strain response of CNTYs elucidates the factors affecting that response and provides critical information towards their use in a variety of applications.

Formulation of interfacial parameter in Kolarik model by aspect ratio of carbon nanotubes and interfacial shear strength to simulate the tensile strength of carbon‐nanotube‐based systems

AbstractIn this work, we formulate the “A” interfacial parameter in Kolarik model by the features of carbon nanotubes (CNTs) and interface. The formulated “A” is applied to develop the Kolarik model for tensile strength of polymer CNT nanocomposites using CNT concentration, CNT aspect ratio, interfacial shear strength, and interfacial stress transfer factor. The advanced equations are applied to approximate the interfacial properties and sample strength. Moreover, the impacts of all factors on the nanocomposite strength are examined to validate the advanced model. CNT size (length and radius) largely changes the “A” from 0 to 250. Both CNT aspect ratio and interfacial stress transfer factor directly manage the “A” and nanocomposite strength. Too thin and extremely large CNTs result in the significant improvement in the strength of nanocomposites, but thick and short CNTs cannot reinforce the polymer media. Very thin (R = 2 nm) and extremely large CNTs (l = 20 μm) cause 1100% improvement in the strength of nanocomposites, whereas R > 12 nm and l < 10 μm cannot strengthen the polymer medium.

One‐stepfabrication of bulk nanocomposites reinforced by carbon nanotube array fragments

AbstractVertically aligned carbon nanotube (VACNT) array growth is an established process where high aspect ratio carbon nanotubes (CNTs) are produced. This work demonstrates one‐step approach to fabricate bulk polymer nanocomposites using CNT array fragments'. Here, 4.5 mm long CNTs were collected post VACNTs synthesis. Next, CNT array fragments were coated with pyrolytic carbon (PyC) and infused with polydimethylsiloxane (PDMS) matrix to create porous CNT/PDMS nanocomposite with a CNT weight fraction of 20%. Achieving similar weight fraction with super long bundled CNTs using dispersion techniques is extremely difficult. The compression and dynamic mechanical behaviors and piezoresistive response of the PDMS filled nanocomposite were assessed. The results revealed the potential of the synthesized structure to serve as fatigue‐resistant pressure sensors with high damping and self‐sensing capabilities. The proposed fabrication technique is versatile, as it can work with thermosetting and thermoplastic polymers in addition to allowing for mass production of PDMS filled nanocomposites.

Toward mechanistic understanding the effect of aspect ratio of carbon nanotubes upon different properties of polyurethane/carbon nanotube nanocomposite foam

AbstractThis study investigated the carbon nanotube's aspect ratio's influence on the nanocomposite foams' cellular structure and mechanical, acoustic absorption characteristics. The free‐rising foaming process has been used for producing different flexible polyurethane (PU) foams embedded with other multi‐walled carbon nanotubes (MWCNT's). Dynamic mechanical and thermal analysis, flow resistivity, and compressive mechanical measurements were achieved on the prepared samples. The acoustic absorption coefficient in a wide range of frequencies was estimated for the prepared PU/CNT foamed nanocomposite samples. Results indicated that by increasing the aspect ratio of MWCNT, the absorption coefficient's peak shifts toward the lower frequencies and improved sound absorption characteristics of PU foam in the low‐frequency region. Moreover, the Young modulus of nanocomposite samples increases by increasing the aspect ratio of MWCNT's, whereas the stored strain energy or area under the stress–strain curve increases. Based on the obtained results, it is observed that the acoustic absorption coefficient of produced nanocomposite foams at the frequency of 800 Hz has been reported to have a 70% improvement in 2 cm samples and a 40% improvement in 3 cm samples compared to obtained results from pure PU foam.

Multiscale modeling and numerical analyses of the electric conductivity of CNT/polymer nanocomposites taking into account the tunneling effect

AbstractTunneling effect plays a significant part in the extremely low electric percolation threshold and large conductivity of carbon nanotube (CNT)/polymer nanocomposites, which allows electric conduction between two CNTs separated at nanometric distances. In this work, a numerical model taking into account the nonlinear tunneling effect is proposed to evaluate the effective electric conductivity of CNT nanocomposites. The nonlinear finite element formulation is introduced, as well as the definitions of effective quantities for homogenization. Moreover, the CNTs are modeled by highly conducting line segments in order to avoid meshing the thin cylindrical tubes. With this technique, the percolation behavior of the composites has been simulated, and the effects of barrier height, CNT length distribution, CNT aspect ratio as well as alignment have been estimated. It turns out that the barrier height dominates the maximum electric conductivity, while the CNT aspect ratio determines the percolation threshold value, respectively. In addition, the anisotropic behavior is obtained by aligning the CNTs, which also results in higher percolation threshold compared with randomly distributed CNTs. Finally, the results are validated by available experimental data.

Electrical conductivity across the alumina support layer following carbon nanotube growth

Several electrical devices are formed by growing vertically aligned carbon nanotube (CNT) structures directly on a substrate. In order to attain high aspect ratio CNT forest growths, a support layer for the CNT catalyst, usually alumina, is generally required. In many cases, it has been found that current can pass from a conductive substrate, across the alumina support layer, and through the CNTs with minimal resistance. This is surprising in the cases where alumina is used because alumina has a resistivity of ρ>1014 Ω cm. This paper explores the mechanism responsible for current being able to cross the alumina support layer with minimal resistance following CNT growth by using scanning transmission electron microscopy imaging, energy dispersive x-ray spectroscopy, secondary ion mass spectroscopy, and two-point current-voltage (I-V) measurements. Through these methods, it is determined that exposure to the carbonaceous gas used during the CNT growth process is primarily responsible for this phenomenon.

Elucidating the interactions between carbon nanotubes and carbon black with styrene butadiene rubber

AbstractThe reinforcement mechanism of carbon nanotubes (CNT) on styrene butadiene rubber is studied through dynamic and swelling tests. Compounds containing carbon black (CB) and an unfilled one were prepared for comparison purposes. The dynamic properties are interpreted through the Maier‐Göritz model to distinguish the contributions of stable and unstable crosslinks to the storage modulus, finding that the unstable ones become more relevant in samples containing a CNT concentration higher than 5 phr. In addition, the crosslinks density estimated by swelling and the stable contribution obtained with dynamical properties present the same tendency with the CNT amount. The former presents lower values, which can be explained considering that only stable crosslinks remain in the equilibrium‐swollen state, while in the second one both stable and unstable are considered. In addition, differences in the filler‐polymer interaction mechanisms are observed according to the morphology and aspect ratio of CNT in contrast to CB.