Carbon Nanotube Sponge Research Articles

Highly Activated Carbon Nanotube Sponges Deposited with Sulfur for Lithium-sulfur Batteries

Highly Activated Carbon Nanotube Sponges Deposited with Sulfur for Lithium-sulfur Batteries

Comparative Study of Nanocarbon-Based Flexible Multifunctional Composite Electrodes.

Although nanocarbon-based nanofillers have been widely used to improve the energy-storing and sensing functions of porous materials, the comparison of the effects of different nanocarbon-based fillers on the capacitive and flexible sensing properties of nanocarbon-based porous sponge composite supercapacitor electrodes by combining a carbon nanotube, graphene, and graphene oxide with porous sponge is incomplete. The specific capacitance of carbon nanotube-based electrodes is 20.1 F/g. The specific capacitance of graphene-based electrodes is 26.7 F/g. The specific capacitance of graphene oxide-based electrodes is 78.1 F/g, and the capacity retention rate is 92.99% under 20 000 charge–discharge cycles. Under a bending load of 180°, the capacitance retention rate of graphene oxide sponge composite electrodes is 67.46%, which indicates that the prepared electrodes of supercapacitor have the advantages of high capacitance and good flexibility at the same time. To demonstrate their performance, an array of three graphene oxide supercapacitors in series was constructed, which could light up a red light-emitting diode (LED). The tensile strength of carbon nanotube sponge composite electrodes is 0.267 MPa, and the tensile linearity is 0.0169. The experimental results show that graphene oxide-based sponge composite supercapacitor electrodes have the best capacitance performance and carbon nanotube sponge composites have the most potential as a flexible sensor.

A theoretical framework representing seminal fire detection system design using shape memory polymer embedded with carbon nanotubes sponge

Abstract In today’s world everyone is conversant with the phenomenon of fire. However, when it is uncontrolled, it takes a massive form and can destroy everything in its path. Fire is defined as a chemical reaction, which includes oxidation of fuel molecules. There are myriad types of fire detection systems available (such as heat detectors, smoke detectors, beam detectors etc.). which can detect the fire, when it occurs at a place. Heat Detectors are those types of detectors which detects fire, when the heat reaches to its maximum preset temperature for instance: 40–55 °C, as per the design and requirement. Sometimes, it may take long time to operate, if fire occurs at some distance from the heat detectors. The paper addresses a theoretical model of the design of seminal detection system which can easily detect the fire even at nook place of the room in a better way by using shape memory polymer embedded with carbon nanotubes. This detection system can also be useful to use in storage areas where chances of occurring fire is more.

Highly resilient, biocompatible, and antibacterial carbon nanotube/hydroxybutyl chitosan sponge dressing for rapid and effective hemostasis.

Uncontrolled hemorrhage is the leading cause of trauma death. The development of safe and efficient hemostatic agents that can rapidly and effectively control bleeding is of great significance to rescue the injured. However, the mechanical, absorptive, and antibacterial properties of conventional two-dimensional hemostatic agents are not satisfactory. Herein, a series of effective three-dimensional hemostatic dressings (JWCNT/HBC sponges) are developed by chemical modification of joint-welded carbon nanotube (JWCNT) sponges with hydroxybutyl chitosan (HBC) for hemorrhage hemostasis. The JWCNT/HBC sponges exhibit high elasticity, porous structure, and suitable blood-absorption and blood-maintaining performance. Moreover, the introduction of HBC endows the JWCNT/HBC sponges with favorable blood compatibility and good antibacterial activity. The sponge treated with 0.5% HBC (JWCNT/0.5%HBC sponge) displays better antiseptic capability, faster blood clotting ability in vitro and shorter hemostasis time in vivo than the commercial gelatin sponge. The JWCNT/HBC sponges combine the advantages of JWCNT sponges and HBC in the adhesion and activation of platelets and red blood cells, thus becoming a good medical material for trauma hemostasis.

An ultra-broad-range pressure sensor based on a gradient stiffness design.

The question of how to make artificial intelligence robots perceive the power of "light as a feather" and "heavy as a mountain" at the same time has always been a goal that people are striving to achieve. However, pressure sensors, the key components of electronic equipment, are often unable to incorporate high sensitivity and wide range performance. Here, we proposed a "gradient stiffness design" strategy to prepare a kind of carbon nanotube sponge with a stiffness difference of up to 254 times between different layers, but still maintaining an integral conductive network without delamination. This gradient stiffness structure sponge shows prominent sensing properties with ultra-broad range (from 0.0022 MPa to 5.47 MPa) and high sensitivity. The low stiffness layer can detect low stress (0.0022 MPa) with high sensitivity of 0.765 MPa-1, and the high stiffness layer can greatly extend the sensing range to an unprecedentedly high value (5.47 MPa). It can concisely detect various motions with different stress, from slight clamping of fragile fries by the robot fingers to heavily stomping motions by a 90 kg person. Moreover, a series of human movements from small-scale to large-scale can be also monitored, revealing the great potential of this gradient stiffness structure in future sensing research.

Improved wettability and enhanced ionic transport in highly porous CNT sponge

We investigated the effect of an electric treatment on the wettability of aqueous solution on carbon nanotubes (CNT) and ion transport behaviors in superhydrophobic porous carbon nanotube sponges (CNTS). This electric activation treatment where an electric voltage was applied across highly porous CNT sponge induced an electrowetting effect. This effect significantly reduced interfacial tensions between CNT sidewalls and aqueous liquids. Meanwhile, polar functional groups were also introduced on CNTs. Both electrowetting effect and polar functional groups greatly improved the wettability of aqueous solutions on CNT sidewalls. After the electric treatment, we observed a dramatic increase in the overall rate of ion flow across porous CNT sponges. The formation of solution channels during the electric treatment is responsible for the enhanced ionic transport in porous CNT sponges. The overall rate of ion flow increased with the increases in electric treatment time and voltage. The crucial role of electric treatment parameters in the ion transport provides a new strategy for precisely controlling the ion transport across CNT sponges by tuning electric treatment time or voltage. Importantly, the good wettability of aqueous solution on CNT sidewalls greatly increased the effective surface area of CNT sponges and thus significantly improved the performance of CNTS-based supercapacitors after the electric treatment.

Tribological properties of vertically aligned carbon nanotube arrays and carbon nanotube sponge

Carbon nanotube (CNT) films showing excellent mechanical and frictional performances are one of the most competitive candidates for fabricating functional surfaces; in particular, the bulk form of the forest-like vertical aligned CNT (VACNT) film and CNT sponge are idea candidates for making a flexible solid lubricant surface due to the fact that their porous network has a high potential to experience large deformation. In this article, the frictional behavior of the VACNT and CNT sponge against a millimeter scale copper sphere has been studied under various conditions within a home-built system. Due to the intrinsic mechanical instability of VACNTs, a higher friction state than the CNT sponge has been observed, and beyond that, VACNTs typically show a run-in process as a function of sliding circle caused by the formation and rearrangement of quasi-periodic cracks; on the contrary, the friction of the CNT sponge is very stable. In addition, we have pinpointed the effects of sliding velocity, relative humidity, and temperature on friction. The sliding friction was observed to be independent of the velocity and temperature; however, due to the increase in capillary force, friction increases with the increase in relative humidity.

Dislocation-Strained IrNi Alloy Nanoparticles Driven by Thermal Shock for the Hydrogen Evolution Reaction.

Designing high-performance and low-cost electrocatalysts is crucial for the electrochemical production of hydrogen. Dislocation-strained IrNi nanoparticles loaded on a carbon nanotube sponge (DSIrNi@CNTS) driven by unsteady thermal shock in an extreme environment are reported here as a highly efficient hydrogen evolution reaction (HER) catalyst. Experimental results demonstrate that numerous dislocations are kinetically trapped in self-assembled IrNi nanoparticles due to the ultrafast quenching and different atomic radii, which can induce strain effects into the IrNi nanoparticles. Such strain-induced high-energy surface structures arising from bulk defects (dislocations), are more likely to be resistant to surface restructuring during catalysis. The catalyst exhibits outstanding HER activity with only 17 mV overpotential to achieve 10mAcm-2 in an alkaline electrolyte with fabulous stability, exceeding state-of-the-art Pt/C catalysts.Thesedensity functional theory results demonstrate that the electronic structure of as-synthesized IrNi nanostructure can be optimized by the strain effects induced by the dislocations, and the free energy of HER can be tuned toward the optimal region.

Spatial Effects between Two 3D Self‐Supported Carbon‐Nanotube‐Based Skeleton as Binder‐Free Cathodes for Lithium‐Sulfur Batteries

AbstractIn this manuscript a deep comparison of the spatial effect is conducted between vertically‐aligned carbon nanotube array (CNTA) and 3D inter‐connected carbon nanotube sponge (CNTS) based self‐supported and adhesive free cathode material for lithium‐sulfur battery. Melt impregnation (M–CNTA/S and M‐CNTS/S) and solution penetration (S‐CNTA/S and S‐CNTS/S) methods are separately carried out to introduce sulfur into two carbon nanotube‐based matrix. Besides, random distributed carbon nanotube powders (RCNT)‐based cathode made through a slurry coating process is also prepared for comparison. As a result, the aligned CNTA skeleton has the most efficient transfer paths and regular nanometer‐sized gaps, which greatly benefit the directional transmission of electrons, better rate performance, smaller cell resistance and long cyclic stability. Especially, the cell made by M‐CNTA/S delivers an outstanding high‐rate performance of 3 C −859.3 mAh g−1, 5 C −833.1 mAh g−1 and 10 C −702.8 mAh g−1, with a capacity retention of 77 % and coulombic efficiency (∼100 %) after 200 cycles at a rate of 3 C. Meanwhile, the interconnected CNTS has a larger pore diameter and 3D conductive network, which benefits higher sulfur loading and electrochemical activity of sulfur. In particular, the M‐CNTS/S with a sulfur content up to 60 wt %, achieves an impressive multiplier performance of 0.5 C 1285 mAh g−1, 1 C 1030 mAh g−1 and 3 C 900 mAh g−1. The retention of the capacity reaches around 88 % after 100 charge‐discharge cycles at 3 C. The current observation reveals the crucial effects from the spatial structure and sulfur impregnation method on the performance of carbon nanotube/sulfur (C/S)‐based cathodes for lithium‐sulfur batteries, which serves as important guidance for the development of high‐performance cathode materials.

A 3D porous nitrogen-doped carbon nanotube sponge anode modified with polypyrrole and carboxymethyl cellulose for high-performance microbial fuel cells

Enhancing anode performance is a critical step to improving the power output and energy storage of microbial fuel cells (MFCs). In this study, MFCs containing pseudocapacitive anode materials, such as polypyrrole-carboxymethyl cellulose (PPy-CMC) composite films, were used to coat the nitrogen-doped carbon nanotube (N-CNT)/sponge (S) for use in MFCs. The capacitive anode could function as a bioanode, store electrons generated from the microbial oxidation of a substrate, and release the accumulated charge as needed. Scanning electron microscopy results indicated that the composite anode had a three-dimensional macroporous structure with a large specific surface area, providing more sites for microbial attachment and growth. Experimental results showed that MFCs equipped with PPy-CMC/N-CNT/S capacitive bioanodes had a maximum power density of 4.88 W m−3, which was 1.34 and 1.71 times as much as those of PPy/N-CNT/S and N-CNT/S bioanodes (3.65 and 2.85 W m−3), respectively. Moreover, the charge–discharge time of 60–90 min, the total charge Qm of the MFC equipped with the PPy-CMC/N-CNT/S anode was the largest (5154.08 mC cm−2)—5.7 times higher than that of the N-CNT/S anode. The excellent performance of the MFC equipped with the PPy-CMC/N-CNT/S anode was attributable to the composite materials, which exhibited a large-pore structure, good biocompatibility, large capacitance, and high specific surface area. Therefore, this synthesized composite exhibited potential as a capacitive and biocompatible anode material in MFCs.

A portable gas chromatograph for real-time monitoring of aromatic volatile organic compounds in air samples

We describe the design and performance evaluation of a portable gas chromatograph suitable for the analysis of volatile organic and odorous compounds at trace levels. The system comprises a carbon nanotube sponge preconcentrator, an electronic pressure control (EPC) unit, a temperature-programmable column module, and a fast-response photoionization detector. A built-in tablet computer controls instrumental parameters and chromatogram display functions. The compact GC with dimensions of 35 cm (l) × 26 cm (w) × 15 cm (h) is self-contained, weighing less than 5 kg without a battery pack, and uses no auxiliary compressed gases. Our design has three main advantages over conventional portable GCs: recharging configuration of ambient air as the carrier gas using a miniature diaphragm pump, precise control of column flow by the built-in canister and EPC system, and rapid thermal desorption of the preconcentrator facilitated by intrinsic resistivity of the carbon nanotube sponge. A 30 m, 0.28 mm I.D. capillary column operated at a head pressure of 14 psi provided a peak capacity of 55 for a 10 min isothermal analysis. The temperature-programmability feature could decrease the analysis time of less than 5 min for vapor mixture of benzene, toluene, ethylbenzene, and o-xylene. More than a 100-fold increase in sensitivity by preconcentrating a sample adsorption volume of 90 mL resulted in improved detection limits of 0.13 (benzene), 0.20 (toluene), 0.23 (ethylbenzene), and 0.28 (o-xylene) ppb (v/v). Our instrument displayed good stability and reproducibility of retention times (< 0.14% RSD) and intensities (< 4.5% RSD) for continuous measurements using the preconcentrator over 10 h. Thus, continuous and on-site determinations of trace volatile organic compounds in air samples with this instrument appear feasible.

Homogeneous silver nanoparticles decorating 3D carbon nanotube sponges as flexible high-performance electromagnetic shielding composite materials

Nowadays flexible high-performance electromagnetic interference (EMI) shielding materials are greatly demanded in military and daily purpose. To yield high shielding effectiveness (SE), the traditional metallic EMI materials always require a large mass of loading in a composite matrix, which is uneconomic and harmful to the mechanical property of the materials. Herein the homogeneous decoration of Ag nanoparticles on a light-weight and robust carbon nanotube sponge (CNTS) based 3D conductive scaffold is introduced. The flexible Ag/CNTS/PDMS composites exhibit an extremely high and tunable EMI shielding performance with improved mechanical strength and high conductivity. The maximum EMI SE is measured to be even greater than 90 dB in the X-band (8–12 GHz) with a low loading of Ag (3%, wt %) and CNTS (4%, wt %). In addition, the 3D inter-connected pore structure enables EM waves to reflect multiple times inside the Ag/CNTS hybrids which results in a strong absorption ability. The total EMI shielding property can be further conveniently controlled by tuning the Ag-deposition parameters as well as the thickness of the sample. The current approach successfully avoids the dispersion problem of the fillers and will be of great importance in development of high-performance EMI shielding materials.

Chloride functionalized carbon nanotube sponge: High charge capacity and high magnetic saturation

A chloride functionalized carbon nanotube sponge (CNS) was produced using the aerosol-assisted chemical vapor deposition method. The CNS was grown using 1,2-dichlorobenzene and ferrocene as precursors. The chloride functionalized CNS was characterized by scanning electron microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometry and cyclic voltammetry (CV). The CNS is formed by entangled multiwalled carbon nanotubes (MWCNTs) of 32 nm diameter with Fe3C nanowires inside. FTIR and XPS demonstrated that the surface of MWCNTs hosts functional groups such as trichloromethyl (CCl3), chloride (C–Cl), carbonyl (CO), carboxylic (COOH), and phenolic (C–O). Magnetic measurements at 300 K revealed a saturation magnetization of 192.7 emu/g and a coercive field of 502 Oe. CV studies show that the iron species and 3.2% oxygen over the surface of CNS leads to a quasi-reversible redox process and hydroquinone/quinone redox process, respectively. High charge capacity is correlated with chloride functionalities. The CNS could be used as a magnetic oil-spill cleaner, anodes in lithium-ion batteries, or specific magnetic-catalyst. Density functional theory calculations reveal the structural stability and charge transfer over chloride functional groups anchored to the surface of MWCNTs.

High-performance Li-ion batteries based on graphene quantum dot wrapped carbon nanotube hybrid anodes

Since Akira Yoshino first proposed the usage of the carbonaceous materials as an anode of lithium ion batteries (LIBs) in 1985, carbonaceous materials such as graphite and graphene have been widely considered as LIB anodes. Here, we explored the application of novel carbonaceous LIB anodes incorporating graphene quantum dots (GQDs). We fabricated a freestanding all-carbon electrode based on a porous carbon nanotube (CNT) sponge via a facile in-situ hydrothermal deposition technique, creating coaxial structure of GQD-coated CNTs (GQD@CNTs) through electrostatic interaction and π-π stacking with tunable loading and functionalization. This hybrid structure combined conductive CNTs with highly active GQDs, in which GQDs with predesigned functional groups provided massive storage sites for Li ions and the 3D CNT frameworks avoided the agglomeration of GQDs, together contributing to a high specific capacity (700 mAh}g−1 at 100 mA}g−1 after 100 cycles) and rate performance. Even at a high current density of 1,000 mA}g−1, the reversible specific capacity remained at 483 mAh}g−1 after 350 cycles. In particular, the mechanism study demonstrated the important role of oxygen functional groups of GQDs in promoting the performance of the LIB anodes by controlled grafting of GQDs onto various porous-carbon and metal-foam based structures.

Construction of Carbon Nanotube Sponges to Have High Optical Antireflection and Mechanical Stability.

Antireflective (AR) materials are required to possess high optical antireflection and mechanical stability for their practical applications in optical, opto-electronic, and electron-optical devices. However, the AR materials developed so far can hardly meet these requirements. Here, we report the construction of a highly porous and sponge-like material based on carbon nanotubes (CNTs). This is achieved by continuous winding of a hollow cylindrical CNT assembly and subsequent modification with amorphous carbon (AC). The resultant material is shown to have very low optical reflectance at the visible and infra-red wavelengths over a wide range of incident angles and undergoes little degradation even after long-lasting compressive cycling between 0 and 90% strains or a large change of environmental temperature from -196 to 300 °C. Besides, the AR sponge material can recover fast after bending, stretching, and compression from high elastic strains. Such an excellent combination of broadband and omnidirectional antireflection, mechanical stability, and elastic flexibility results from the strong light absorption by the highly porous CNT structures strengthened by AC deposition on CNT surfaces and junctions, and the new AR material has potential applications in the renewable energy and military fields.

Furan and Pyran Functional Groups Driven the Surface of Nitrogen‐Doped Nanofiber Sponges

AbstractHighly surface oxidized, nitrogen‐doped, and nitrogen functionalized carbon nanotube sponge (N‐CFS) were produced at 1020 °C using two sprayers approach in an aerosol‐assisted chemical vapor deposition (AACVD) experiment. The structure of N‐CFS consisted of entangled and corrugated carbon nanofibers of ∼200 nm diameter, also showing junctions and knots. TEM characterizations revealed that the carbon nanofiber exhibits stacked graphitic layers in a transversal way with positive curvature. Superficial chemical analysis by XPS showed that the N‐CFSs contain an atomic concentration of oxygen and nitrogen of 9.2% and 2.9%, respectively. The high‐resolution XPS scans deconvolution‐analysis revealed high percentages for C−O bonds, pyrrolic nitrogen doping, NH3 functionalization, and Si−C interactions. The cyclic voltammetry measurements did not display a redox process despite the high oxygen concentration at the surface. Hydrophobic functional groups containing C−O bonds do not participate in a redox process (furan, pyran, epoxy, methoxy, ethoxy, among others) could mostly determine the electroactivity of N‐CFS. Based on density functional theory calculations, we determine that the furans transfer a high amount of electron and promote a positive curvature in thin carbon nanotubes. Graphitic materials with furans, pyrans, and epoxy functional groups could be used as an anode in lithium‐ion batteries.

Ultrahigh-Sensitive Finlike Double-Sided E-Skin for Force Direction Detection.

Flexible pressure sensing is required for the excellent sensing performance and dexterous manipulation of the measured objects in their potential applications. Particularly, the ability to measure and discriminate the direction of force, contact surface, and contact location in real time is crucial for robotics with tactile feedback. Herein, a three-dimensional elastic porous carbon nanotube (CNT) sponge is synthesized by chemical vapor deposition, which is successfully applied in the piezoresistive sensor. In situ scanning electron microscopy study intuitively illustrates the characteristics that the microfibers of the CNT sponge distort and contact with each other under an external force. As a result, new conductive paths are created at the contact points between the CNT microfibers, which provides a basic sensing principle for a piezoresistive sensor. The CNT sponge-based sensor has an ultrahigh sensitivity in a wide pressure range (0-4 kPa for 4015.8 kPa-1), a rapid response time of 120 ms, and excellent durability over 5000 cycles. Moreover, a finlike flexible double-sided electronic skin (e-skin) is fabricated by a simple method to achieve force direction detection, which has potential applications in intelligent wearable devices and human-machine interaction.

Recent advances in carbon nanotube sponge–based sorption technologies for mitigation of marine oil spills

HypothesisOil spills stemming from supertankers, drilling, and natural events represent a serious problem worldwide due to the potential harms to marine ecosystems and aquatic life. To date, various functional absorbents have been developed to treat spilled oil. Among them, carbon nanotube (CNT)-based aerogels and sponges gained attention due to superior performance in uptake and recovery of various types of oil and organic solvents. CNT aerogel/sponge absorbents are demonstrated for a multitude of merits such as: rapid superhydrophobic/superoleophilic absorption (water contact angle > 150°), high capacity (≥100 mg g−1), large surface area (300–400 m2 g−1)), enhanced strength and flexibility (>95% volume reduction and restoration of pristine morphology at <0.25 MPa stress), mesoporous characteristics with high pore density (pore diameter = 80 nm and >99% porosity), recyclability, and easy surface modification. ExperimentsThis review compares CNT sponge–based absorbents with conventional techniques for remediation/recovery of spilled oil. Typically, synthesis of CNT sponges is performed using chemical vapor deposition (CVD) approach in the presence of a catalyst or using sacrificial removal of template. This work summarizes recent progress in strategies for oil-spill treatment based on CNT sponge techniques. The performance of CNT sponges for oil spill removal was evaluated in terms of their adsorption capacity, compressive stressability, and desorption methods (e.g., heat treatment, burning, or squeezing). FindingsCNT sponges were observed to have high performance for removal of oil spills in terms of key performance metrics. This review offers valuable insights into the current state of CNT-mediated oil-spill cleanup technologies and guidance for future research at the same time. This literature survey would help the stakeholders (researchers, scientists, entrepreneurs, and commercial houses) pursue contamination-free water.

High-energy density LixSi-S full cell based on 3D current collector of few-wall carbon nanotube sponge

For the practical use of innovative, high-energy-density batteries, loading of high-capacity active materials at high gravimetric and volumetric fractions is required. In this work, a flexible self-supporting paper of few-wall carbon nanotubes (FWCNTs) was used as three-dimensional conductive matrices to capture Si and S at ∼70 mass% without metal foils nor polymeric binders. The full cell comprised of the LixSi-CNT and S-CNT electrodes with a negative to positive (N/P) capacity ratio of ∼1 realized high initial energy densities of 810 W h kg−1 and 680 W h L−1 based on the total mass and volume of the electrodes, respectively. However, the cell showed a poor cycle performance due to the depletion of active Li. The increased N/P capacity ratio of 2.7 drastically improved the cycle performance, realizing an energy density of 610 W h kg−1 at first discharge and 360 W h kg−1 after 100 cycles based on the total mass of the electrodes. The full cell architecture based on 3D current collector of FWCNTs is a promising solution for loading active materials at high fractions and achieving high energy densities at the total electrode level.

A new strategy to prepare carbon nanotube thin film by the combination of top-down and bottom-up approaches

Bottom-up and top-down are two different strategies to prepare nano-materials and their assemblies, each with their own pro-and-cons. Here, we demonstrate a combined approach in preparing large area uniform carbon nanotube (CNT) thin films within minutes, several orders of magnitude faster than conventional methods. This strategy takes full advantage of the unique micro-structure of CNT sponges, synthesized by a bottom-up process and composed of physically entangled CNTs with uniform size and spatial distribution. Such a 3D network structure allows us to firstly transfer certain amount of structured CNTs from the sponge onto a Scotch tape. Through a second-step stamping process, which is essentially a top-down process, transparent and conductive (TCF) CNT films with controlled micro-structures are produced on viscous substrates. Bonding strength between the stamped CNT network and elastomer substrate can be adjusted to optimize the physical properties including the transparency and sheet resistance of the CNT thin films. Upon stretching, the device exhibits high piezoresistive responsiveness; combining high sensitivity, low hysteresis and large working strain range. The proposed methodology had been extended to fabricate micro-electrodes on patterned elastomers with same effectiveness. These experimental results highlight the high efficiency, low-cost and versatility of this approach in preparing TCF electrodes with different sizes and shapes.