Electrophoretic Deposition Of Carbon Nanotubes Research Articles

The effect of electrophoretic deposition of carbon nanotubes on carbon fiber on interfacial properties of the thermoplastic polyimide composite

In order to improve the interfacial properties of carbon fiber/polyimide (CF/PI) composite, silanization reaction carbon nanotubes (CNTs) were introduced to the surface of carbon fiber by electrophoretic deposition to prepare CF/CNT/PI composite. The effects of carbon fiber surface treatment on the mechanical properties of the composites were studied. The results showed that the interlaminar shear strength and bending strength of the composite materials were increased by 11% and 9%, respectively. The scanning electron microscope and Atomic Force Microscope (AFM) was used to analyze the fine structure of composite interface phase. The results show that the introduction of CNTs creates an interface transition layer of CNTs reinforced PI resin between the fiber and the matrix.

The effect of electrophoretic deposition of carbon nanotubes onto carbon fiber on the interlaminar resistance of carbon reinforced aluminum laminates

Functionalized multi-walled carbon nanotubes were deposited on the carbon fabric using ultrasonic-assisted electrophoretic deposition. The effect of carbon nanotubes (CNTs) deposition time and morphology on the mode I interlaminar fracture resistance of carbon reinforced aluminum laminates (CARALL) was investigated. The formation of a proper network of CNTs on the carbon fabric favorably deviated the crack growth into the carbon fabric layer and intensified the fiber bridging during the delamination. The CNT coating on the carbon fiber in conjunction with the alkaline-acid treatment on the Al substrate significantly promoted the interlaminar fracture initiation and propagation energies and stabilized the fracture behavior.

Electrophoretic deposition of carbon nanotubes on aluminium for capacitor application

ABSTRACT Multiwalled carbon nanotubes (MWCNT) were electrophoretically deposited from an environmentally friendly aqueous solution on aluminium current collectors which were carbon coated by physical vapour deposition. The carbon coating proved to be stable under electrophoretic deposition (EPD) conditions up to EPD voltage of U = 50 V and avoided any undesirable oxidation of the aluminium during the deposition process. The kinetics of the deposition was described and could be easily controlled by the suspension concentration and the deposition time. The deposition rate at U = 50 V is about 0.03 mg cm−2 min−1. As anodic oxide formation could be prevented the electrical contact to the current collector was improved allowing the surface area to be increased by MWCNT to be used as a double-layer capacitor. The gravimetric capacitance obtained was about 8 F g−1.

Electrophoretic deposition of carbon nanotubes: recent progress and remaining challenges

ABSTRACT Electrophoretic deposition (EPD) is a powerful technique to assemble carbon nanotube (CNT) coatings and composite films with controlled architectures. This comprehensive review of the EPD of CNTs and CNT-containing composites focuses on achievements within the last 15 years and ongoing challenges. Stable CNT suspensions are a pre-requisite for successful EPD and have been prepared by a variety of strategies, discussed here. The resulting film microstructure is determined by the initial feedstock, the suspension, and the EPD approach applied, as well as a variety of EPD processing parameters. Nanocomposites can be prepared via co-deposition, sequential deposition, or post-deposition treatments, to introduce metallic, ceramic or polymeric phases. There are numerous potential applications for both homogeneous and patterned CNT films, including as structural reinforcements for composites, as field emission, energy storage and conversion devices, as well as in biomedical applications. The advantages and disadvantages of EPD processing in these contexts are discussed.

Electrophoretic deposition of carbon nanotubes on semi-conducting and non-conducting substrates

Electrophoretic deposition (EPD) is useful for conductive substrates, where a requisite electrical path can be formed. In order to make EPD more broadly applicable for semi-/non-conducting substrates, e.g. EPD of carbon nanotubes (CNTs) on silicon and rubber, we proposed and demonstrated a simple modified EPD set-up. The substrate was directly attached to a conductive electrode at the top end, while a porous separator was placed between the lower parts of the substrate and the electrode which submerged in the CNTs suspension. The separator allowed the suspension moving through its micro-pores to reach the steel to form the requisite conductive path but hindered most CNTs from moving and attaching to the steel. Therefore, CNTs were successfully deposited on the semi-/non- conducting silicon/rubber in a simple single-step process by using the modified EPD set-up. We believe this EPD set-up can be applied to the deposition of versatile particles on various semi-/non-conducting substrates.

Electrophoretic deposition of carbon nanotubes onto glass fibers for self-sensing relaxation-induced piezoresistivity of monofilament composites

Electrophoretic deposition (EPD) in water using a continuous filament process was used to modify E-type glass fibers (GFs) by depositing multiwall carbon nanotubes (MWCNTs) onto their surface. The oxidized MWCNTs behaved as negatively charged particles and migrated toward the positive electrode, containing the GFs. This electrokinetic motion was confirmed by measuring the point of zero charge and Z-potential. The influence of the main EPD parameters on the morphology and electrical properties of the MWCNT-coated GFs is investigated. The most uniform coverage was achieved by using an electric field of 4.5 kV/m for 30 min under a warm bath temperature (~ 50 °C). Higher intensity of the electric field or longer deposition times was not beneficial for the homogeneity of the deposit. The application of these electroconductive MWCNT-modified fibers as smart materials was demonstrated by conducting relaxation-induced piezoresistive experiments in monofilament polymer composites using these MWCNT-modified fibers.

Tailored glass fiber interphases via electrophoretic deposition of carbon nanotubes: Fiber and interphase characterization

Electrophoretic deposition (EPD) has been used to deposit carbon nanotubes (CNTs) onto glass fibers to strengthen the fiber/matrix interphase of glass/epoxy composites. CNTs were functionalized using an ultrasonicated-ozonolysis followed by polyethyleneimine (PEI) treatment, creating a stable, aqueous dispersion suitable for EPD. Single E-glass fiber filaments were successfully coated with the functionalized CNTs using EPD. Single fiber tensile and microdroplet debond tests were conducted to investigate the tensile properties of the CNT modified E-glass fibers and their interfacial structure and properties in an epoxy matrix, respectively. Weibull analysis of the fiber testing revealed no detrimental effects resulted from the CNT coating, with some evidence to suggest slightly improved strength. Microdroplet tests revealed changes in the fracture modes due to the application of the CNT coating. The interfacial shear-sliding shifted from the fiber/resin interface to the CNT/resin interphase for the CNT modified fibers. Higher effective interfacial shear strength corresponded to the results where fracture propagated deeper into the CNT-rich interphase layer, confirming the trends observed in previous model interphase studies.

Electrophoretic deposition of carbon nanotubes for improved ablation resistance of carbon/carbon composites

CNTs have been introduced into C/C composites by electrophoretic deposition to improve their ablation performance. Mass ablation of C/C composites decreases by 64% with an optimized CNT content. Mechanical exfoliation is mainly responsible for the mass loss of C/C composites under oxyacetylene ablation as confirmed by SEM observations and static oxidation experiments. By applying CNTs with an optimized content, thermal conductance of the composites increases by 24.5% and the fiber-matrix interfacial strength increases by 74.6%. Local thermal damage is significantly relieved and matrix peeling off by high-velocity gas is inhibited, which lead to the significant decrease of mechanical ablation.

RETRACTED: Investigations on electrophoretic deposition of carbon nanotubes on glass textures to improve polymeric composites interface

Abstract In order to improve the interlaminar shear strength (ILSS) of glass fiber reinforced polymers (GFRPs), the fiber/matrix interface has been enriched via chemical robust bonds between glass fiber surface and carbon nanotubes (CNTs). Electrophoretic deposition (EPD) utilized to form a homogenous layer of CNTs on the chemically activated glass fibers. Initially, experimental studies on the electric field, suspension concentration and EPD duration conducted to find optimum EPD parameters for deposition. Then, various GFRP specimens manufactured to evaluate the effect of fiber's surface modification on ILSS of nanocomposites. Regarding most stable process and best quality of CNT deposition, the current density of EPD recorded between 0.5 and 1 mA/cm2. Field strength enhanced deposition mass around 8.5 times, but the concentration effect was around 5.5. Current density diagram was steady in stable processes and the first 3 min of EPD known as effective deposition time. The straightening influence of CNT deposition in composite's interface observed more effective than other treatment techniques. CNT deposition on surface of glass fibers improved the ILSS of GFRPs by 18.2% & 41.5% compared with simple and de-sized control samples, respectively.

Effect of electrophoretic deposition of carbon nanotubes on the tensile behaviors of carbon fiber tow

The effect of carbon nanotubes introduced by electrophoretic deposition on the tensile behavior of carbon fiber tow was investigated. As-received and heat-treated carbon fiber tows that deposited with carbon nanotubes and their counterparts were tested under monotonous tensile loading. Morphology and presence state of carbon nanotubes on the surface of carbon fiber tows were observed for determining the role of carbon nanotubes. Results showed that tensile properties of carbon fiber tow were not damaged by the electrophoretic deposition process. Due to the uniformly distributed carbon nanotubes network on the surface of carbon fiber tow, the fracture of filaments were obviously constrained by carbon nanotubes instead of instantaneous separation. What’s more, carbon nanotubes exhibited a stronger confining ability for heat-treated carbon fiber tow and improved their tensile properties significantly.

Nanomaterial-modified Flexible Micro-electrode Array by Electrophoretic Deposition of Carbon Nanotubes

Micro-electrode arrays (MEAs) and micro-electrodes are used in a variety of medical applications for recording action potentials or stimulating neurons. To have an excellent signal-to-noise ratio, the contact between the neuronal tissue and the micro-electrodes must be very close. Therefore, a flexible MEA with a large number of electrodes on a large area is necessary. In this work, a flexible micro-electrode array (MEA) with an integrated flexible CMOS-chip was designed and fabricated. By connecting several of these MEAs by a bus system, the number of electrodes and therefore the spatial resolution can be increased extremely. Because of the small size of the micro-electrodes (<120 µm) each electrode needs a high charge delivery capacity and a high “true” surface area for stimulation, respectively. This can be obtained by coating the electrodes by disordered multi-walled carbon nanotubes (MWCNTs). Direct current pulsed Electrophoretic Deposition (EPD) has been proved successfully for the aforementioned application. The effective deposition time and the pulse width were figured out to create ideal MWCNT-electrode properties, particularly, with regard to the enhancement of the “true” surface area, microscopic homogeneity and reproducibility of the layer.

Study of electrospray assisted electrophoretic deposition of carbon nanotubes on insulator substrates

In recent years, electrophoretic deposition (EPD) has been adopted as a cost-effective and reliable single-step solution-based room temperature coating method for carbon nanotubes (CNTs), predominantly on conducting surfaces. Contrary to this general pre-requisite of conductive target substrates, in this work we have explored a fabrication strategy for the scalable deposition of CNTs on insulating glass surfaces by the sequential combination of electrospraying and the EPD technique. This combined process flow has been referred to as “electrospray-assisted EPD”, where an initial CNT coating on glass substrates is obtained by electrospraying which, in turn, further assists CNT film growth by EPD. The successful integration of the electrospray technique in the EPD process flow also eliminates the need for surface functionalization of the insulator substrates prior to the deposition step. Electrospray-assisted EPD has resulted in the successful fabrication of uniform, homogenous, and thick CNT deposits (∼4.5 - 5 μm) with precise thickness control. A detailed investigation of the effect of the initial electrosprayed coating on the final CNT film growth and thickness is also presented in this report. This research endeavor presents a significant opportunity for the integration of this deposition model into a wider platform of materials research and technology, chemical sensing, and applications based upon printable and flexible electronics.

Controlled modification of carbon nanotubes and polyaniline on macroporous graphite felt for high-performance microbial fuel cell anode

Polyaniline (PANI) was electropolymerized on the surface of macroporous graphite felt (GF) followed by the electrophoretic deposition of carbon nanotubes (CNTs). The as-prepared macroporous material was characterized by scanning electron microscopy, water contact angle goniometry and electrochemical techniques. Upon the modification of PANI, a rough and nano-cilia containing film is coated on the surface of the graphite fibers, transforming the surface from hydrophobic to hydrophilic. The subsequent modification by CNTs increases the effective surface area and electrical conductivity of the resulting material. The power output of a mediator-free dual-chamber microbial fuel cell (MFC) constructed from the GF anode and an exoelectrogen Shewanella putrefaciens increases drastically with the CNT modification. The CNT/PANI/GF MFC attains an output voltage of 342 mV across an external resistor of 1.96 kΩ constant load, and a maximum power density of 257 mW m−2, increased by 343% and 186%, compared to that of the pristine GF MFC and the PANI/GF MFC, respectively. More bacteria are attached on the CNT/PANI/GF anode than on the PANI/GF anode during the working of the MFC. This strategy provides an easy scale-up, simple and controllable method for the preparation of high-performance and low-cost MFC anodes.

Synthesis of an architectural electrode based on manganese oxide and carbon nanotubes for flexible supercapacitors

We report the synthesis of an architectural electrode by electrophoretic deposition of carbon nanotubes (CNTs) on a graphite sheet (GS) substrate, followed by electrodeposition of manganese oxide (MnO2) nanoclusters into a three-dimensional network structure of CNT to form MnO2 embedded-CNTs/GS. The novel architecture, in which disconnected MnO2 nanoclusters were embedded in an interconnected 3D CNT network, was beneficial to improve the electrochemical utilization of MnO2 for charge storage. Therefore, the MnO2 embedded-CNTs/GS showed a fairly high specific capacitance of 540.7F/g (based on MnO2), an excellent rate capability and a good cycling stability (less 10% loss of its initial capacitance after 1000 cycles).

Electrophoretic deposition of carbon nanotubes onto carbon fiber felt for production of carbon/carbon composites with improved mechanical and thermal properties

Carbon nanotubes (CNTs) were introduced into carbon fiber felts by electrophoretic deposition (EPD) and then pyrocarbon (PyC) was infiltrated in the felts by thermal gradient chemical vapor infiltration using methane as precursor to prepare carbon nanotube (CNT) reinforced carbon/carbon composites (CNT-C/C composites). The effects of CNTs by EPD on microstructure, mechanical and thermal properties of carbon/carbon (C/C) composites were investigated. Results showed that CNTs had complicated effects on the microstructure of PyC in CNT-C/C composites: PyC next to carbon fiber (CF) was isotropic texture and PyC far from CF showed medium texture, while PyC in C/C composites without CNTs (REF-C/C composites) presented low texture. Compared with REF-C/C composites, compressive strength and modulus of CNT-C/C composites were increased by 37% and 19%, respectively, and fracture mode of the composites changed from pseudo-plastic fracture to brittle fracture; coefficient of thermal expansion of CNT-C/C composites in the direction perpendicular to carbon fiber plies was decreased by 30%.

Electrophoretic Deposition of Carbon Nanotubes over TiO2 Nanotubes: Evaluation of Surface Properties and Biocompatibility.

Titanium (Ti) is often used as an orthopedic and dental implant material due to its better mechanical properties, corrosion resistance, and excellent biocompatibility. Formation of TiO2 nanotubes (TiO2 NTs) on titanium is an interesting surface modification to achieve controlled drug delivery and to promote cell growth. Carbon nanotubes (CNTs) possess excellent chemical durability and mechanical strength. The use of CNTs in biomedical applications such as scaffolds has received considerable attention in recent years. The present study aims to modify the surface of titanium by anodizing to form TiO2 NTs and subsequently deposit CNTs over it by electrophoretic deposition (EPD). Characteristic, biocompatibility, and apatite forming ability of the surface modified samples were evaluated. The results of the study reveal that CNTs coating on TiO2 nanotubes help improve the biological activity and this type of surface modification is highly suitable for biomedical applications.

Electrophoretic Deposition of Multi-walled Carbon Nanotube on a Stainless Steel Electrode for use in Sediment Microbial Fuel Cells

Sediment microbial fuel cells (SMFCs) could be used as power sources and one type of new technology for the removal of organic matters in sediments. In order to improve electrode materials and enhance their effect on the performance, we deposited multi-walled carbon nanotube (MWNT) on stainless steel net (SSN). Electrophoretic deposition technique as a method with low cost, process simplicity, and thickness control was used for this electrode modification and produced this novel SSN-MWNT electrode. The performances of SMFCs with SSN-MWNT as electrode were investigated. The results showed that the maximum power density of SMFC with SSN-MWNT cathode was 31.6 mW m(-2), which was 3.2 times that of SMFC with an uncoated stainless steel cathode. However, no significant increase in the maximum power density of SMFC with SSN-MWNT anode was detected. Further electrochemical analysis showed that when SSN-MWNT was used as the cathode, the cathodic electrochemical activity and oxygen reduction rate were significantly improved. This study demonstrates that the electrophoretic deposition of carbon nanotubes on conductive substrate can be applied for improving the performance of SMFC.

Electrophoretic Deposition of Carbon Nanotubes Using New Dispersing and Charging Agents

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Hierarchical Composite Structures Prepared by Electrophoretic Deposition of Carbon Nanotubes onto Glass Fibers

Carbon nanotube/glass fiber hierarchical composite structures have been produced using an electrophoretic deposition (EPD) approach for integrating the carbon nanotubes (CNTs) into unidirectional E-glass fabric, followed by infusion of an epoxy polymer matrix. The resulting composites show a hierarchical structure, where the structural glass fibers, which have diameters in micrometer range, are coated with CNTs having diameters around 10-20 nm. The stable aqueous dispersions of CNTs were produced using a novel ozonolysis and ultrasonication technique that results in dispersion and functionalization in a single step. Ozone-oxidized CNTs were then chemically reacted with a polyethyleneimine (PEI) dendrimer to enable cathodic EPD and promote adhesion between the CNTs and the glass-fiber substrate. Deposition onto the fabric was accomplished by placing the fabric in front of the cathode and applying a direct current (DC) field. Microscopic characterization shows the integration of CNTs throughout the thickness of the glass fabric, where individual fibers are coated with CNTs and a thin film of CNTs also forms on the fabric surfaces. Within the composite, networks of CNTs span between adjacent fibers, and the resulting composites exhibit good electrical conductivity and considerable increases in the interlaminar shear strength, relative to fiber composites without integrated CNTs. Mechanical, chemical and morphological characterization of the coated fiber surfaces reveal interface/interphase modification resulting from the coating is responsible for the improved mechanical and electrical properties. The CNT-coated glass-fiber laminates also exhibited clear changes in electrical resistance as a function of applied shear strain and enables self-sensing of the transition between elastic and plastic load regions.

Electrophoretic Deposition of Carbon Nanotubes for Interconnections in Microelectronics

ABSTRACTCarbon nanotubes (CNTs) have been considered as a promising interconnect material to replace the solder bump used in the flip chip package because of their special electrical, mechanical and thermal properties, which may promote both the performance and reliability of the flip chip packaging. In this paper, electrophoretic deposition (EPD) of CNTs on substrates has been demonstrated for the interconnect application. EPD is a simple, low cost and high throughput process that is capable to produce densely packed film with good homogeneity at low temperature. By altering the electric fields and deposition time during the EPD process, the thickness of the CNTs film could be controlled. In this study, multi-walled carbon nanotubes (MWCNTs) were successfully coated on the various substrates using the EPD method. A highly uniform CNTs microstructure film with thickness over 5 µm was achieved. In addition, the selective depositions of CNTs on the pre-defined bond pads to form CNTs bumps were also accomplished. By employing typical flip-chip bonding technique, high density CNTs bumps were aligned to form a test chip/host substrate interconnects. The electrical conductivity of the CNTs interconnects was carried out using four-point probe measurement. Reliable electrical contacts with linear relationship in the current-voltage (I-V) characteristic suggesting ohmic behaviour were attained. The overall resistances extracted were also relatively low. These superior electrical properties have demonstrated that the CNTs bumps deposited using EPD method is a viable way to serve as an alternative to current metal solder interconnects material such as Sn-Pb alloys. Hence, it offers a promising interconnect application in the quest for device miniaturization in microelectronic industry.