Single-walled Carbon Nanotube Networks Research Articles

Large-Area Flexible Carbon Nanofilms with Synergistically Enhanced Transmittance and Conductivity Prepared by Reorganizing Single-Walled Carbon Nanotube Networks.

Large-area flexible transparent conductive films (TCFs) are highly desired for future electronic devices. Nanocarbon TCFs are one of the most promising candidates, but some of their properties are mutually restricted. Here, a novel carbon nanotube network reorganization (CNNR) strategy, that is, the facet-driven CNNR (FD-CNNR) technique, is presented to overcome this intractable contradiction. The FD-CNNR technique introduces an interaction between single-walled carbon nanotube (SWNT) and Cu─-O. Based on the unique FD-CNNR mechanism, large-area flexible reorganized carbon nanofilms (RNC-TCFs) are designed and fabricated with A3-size and even meter-length, including reorganized SWNT (RSWNT) films and graphene and RSWNT (G-RSWNT) hybrid films. Synergistic improvement in strength, transmittance, and conductivity of flexible RNC-TCFs is achieved. The G-RSWNT TCF shows sheet resistance as low as 69Ωsq-1 at 86% transmittance, FOM value of 35, and Young's modulus of ≈45MPa. The high strength enables RNC-TCFs to be freestanding on water and easily transferred to any target substrate without contamination. A4-size flexible smart window is fabricated, which manifests controllable dimming and fog removal. The FD-CNNR technique can be extended to large-area or even large-scale fabrication of TCFs and can provide new insights into the design of TCFs and other functional films.

Construction of Hierarchical Conductive Networks for LiNi0.8Mn0.1Co0.1O2 Cathode toward Stable Cycling at High Areal Mass Loadings.

Realizing high-performance thick electrodes is considered as a practical strategy to promote the energy density of lithium-ion batteries. However, establishing effective transport pathways for both lithium-ions and electrons in a thick electrode is very challenging. This study develops a hierarchical conductive network structure for constructing high-performance NMC811 (LiNi0.8Mn0.1Co0.1O2) cathode toward stable cycling at high areal mass loadings. The hierarchical conductive networks are composed of a Li+/e- mixed conducting interface (lithium polyacrylate/hydroxyl-functionalized multiwalled carbon nanotubes) on NMC811 particles, and a segregated network of single-walled carbon nanotubes in the electrode, without any additional binders or carbon black. Such strategy endows the NMC811 cathode (up to 250µm and 50mg cm-2) with low porosity/tortuosity, ultrahigh Li+/e- conductivities and excellent mechanical property at low carbon nanotube content (1.8 wt%). It significantly improves the electrochemical reaction homogeneity along the electrode depth, meanwhile effectively inhibits the side reactions at the electrode/electrolyte interface and cracks in the NMC particles during cycling. This work emphasizes the crucial role of the electronic/ionic cooperative transportation in the performance deterioration of thick cathodes, and provide guidance for architecture optimization and performance improvement of thick electrodes toward practical applications, not just for the NMC811 cathode.

Facile fabrication of single-walled carbon nanotubes@cerium oxide composite sensing platform for ultrasensitive electrochemical analysis of methyl parathion

We proposed a simple and feasible strategy to fabricate the nano-structured cerium oxide (CeO2) nanoparticles decorated single-walled carbon nanotubes networks (SWCNT@CeO2), which was utilized to fabricate the SWCNT@CeO2/GCE sensor for detecting methyl parathion (MP) with high sensitivity. SWCNT possessed the unique one-dimensional hollow nanostructure with excellent conductivity performance, which boosted the charge diffusion rate. CeO2 with good biocompatibility and high catalytic capacity could achieve the adsorption of MP molecules on the surface of sensing electrode due to the affinity of CeO2 nanoparticles towards the phosphate groups of MP. Furthermore, SWCNT could effectively make up for the inherent disadvantage of CeO2 nanoparticles in the term of electrical conductivity. The fabricated SWCNT@CeO2/GCE sensor achieved the ultrasensitive MP electrochemical analysis property (LOD: 9.12 nM). The satisfactory repeatability, reproducibility, anti-interference abilities were obtained at the fabricated sensor. Regarding the electrochemical detection of MP in real food samples, both satisfactory recovery rates of 87.68–107.31% and low RSD of 1.09–2.65% suggested the favorable application prospect of SWCNT@CeO2/GCE sensor in the field of pesticide residue analysis.

Evaluating the Efficiency of Boron Nitride Coating in Single-Walled Carbon-Nanotube-Based 1D Heterostructure Films by Optical Spectroscopy.

Single-walled carbon nanotube (SWCNT) films exhibit exceptional optical and electrical properties, making them highly promising for scalable integrated devices. Previously, we employed SWCNT films as templates for the chemical vapor deposition (CVD) synthesis of one-dimensional heterostructure films where boron nitride nanotubes (BNNTs) and molybdenum disulfide nanotubes (MoS2NTs) were coaxially nested over the SWCNT networks. In this work, we have further refined the synthesis method to achieve precise control over the BNNT coating in SWCNT@BNNT heterostructure films. The resulting structure of the SWCNT@BNNT films was thoroughly characterized using a combination of electron microscopy, UV-vis-NIR spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and Raman spectroscopy. Specifically, we investigated the pressure effect induced by BNNT wrapping on the SWCNTs in the SWCNT@BNNT heterostructure film and demonstrated that the shifts of the SWCNT's G and 2D (G') modes in Raman spectra can be used as a probe of the efficiency of BNNT coating. In addition, we studied the impact of vacuum annealing on the removal of the initial doping in SWCNTs, arising from exposure to ambient atmosphere, and examined the effect of MoO3 doping in SWCNT films by using UV-vis-NIR spectroscopy and Raman spectroscopy. We show that through correlation analysis of the G and 2D (G') modes in Raman spectra, it is possible to discern distinct types of doping effects as well as the influence of applied pressure on the SWCNTs within SWCNT@BNNT heterostructure films. This work contributes to a deeper understanding of the strain and doping effect in both SWCNTs and SWCNT@BNNTs, thereby providing valuable insights for future applications of carbon-nanotube-based one-dimensional heterostructures.

Evaluating SWCNT assembly properties from the temperature dependence of electrical resistivity

We developed a theoretical model to describe the electrical resistivity in films and fibers made of single-walled carbon nanotubes (SWCNTs). The proposed model considers the formation of randomly oriented bundles of metallic and semiconducting nanotubes and takes into account the influence of temperature, while separating contributions of SWCNTs and their junctions to the total resistivity. To verify the model, we applied a powerful experimental tool – measurements of the temperature dependence of electrical resistivity of the investigated macroscopic SWCNT assemblies (pristine and doped SWCNT fibers). This allowed us to estimate various parameters of the material, such as the average length of SWCNT bundles, the acoustic phonon scattering length, and the bundle contact resistance, which are difficult to evaluate experimentally for entangled SWCNTs. The study highlights the importance of understanding the relationship between structural characteristics and electrical properties in SWCNT assemblies. The findings provide insights into optimizing the conductivity of these materials and offer a quick estimation method of the SWCNT network properties based on varying temperature measurements for future fiber and film-based applications.

Ultrasensitive electrochemical sensing platform based on Zr-based MOF embellished single-wall carbon nanotube networks for trace analysis of methyl parathion

In this work, a novel electrochemical sensor was designed based on Zr-based metal–organic framework (UIO-66) nanoparticles embellished single-wall carbon nanotube networks (SCN) for the detection of methyl parathion (MP). The synergistic combination of SCN and UIO-66 nanoparticles could fully exert each advantage to boost the MP electrochemical sensing analysis performance. SCN with one-dimensional hollow nanostructures formed three-dimensional interconnected carbon conductive networks, which possessed excellent conductive properties and acceptable specific surface area, enabling efficient transport of electrons and ions. UIO-66 nanoparticles with Zr-OH groups contributes and porous structure to the good affinity for phosphate groups on MP molecules, which enhanced the selective recognition and enrichment capability of sensing electrode towards MP. Under the multifunctional integration of SCN and UIO-66 nanoparticles, the SCN@UIO-66/GCE sensor could present satisfactory MP electrochemical detection performance (LOD: 8.05 nM, linear MP concentration range: 0.01–10 μM). The satisfactory practical property was realized at the SCN@UIO-66/GCE sensor with satisfactory recovery rates of 98.28–101.95 % and low RSD of 1.23–3.01 % for the electrochemical detection of MP in orange juice and lettuce samples.

Bi2Se3@SWCNT heterostructures with beyond theoretical capacity as perspective binder-free anodes for lithium-ion batteries

Bi2Se3 has shown potential for implementation as an anode material for lithium-ion batteries (LIBs), however, the significant volume expansion and dissolution of selenium pose major challenges. In this work, Bi2Se3 nanostructures are synthesized by physical vapor deposition directly on top of a single-wall carbon nanotube (SWCNT) network to fabricate a binder-free Bi2Se3@SWCNT anode materials with different Bi2Se3/SWCNT ratios. Nanostructuring the Bi2Se3 directly on the top of the SWCNT network provides a large accessible contact area and improves mechanical and electrical contact. The heterostructures exhibit capacity, that is beyond the theoretical of pristine Bi2Se3, which can be attributed to the binding of the Se to C, resulting in the resilience against the dissolution of Se, while providing additional electron transport pathways and increased capacitive contribution. A Bi2Se3@SWCNT anode with a mass ratio of (1:1) has the highest capacity in a half-cell after 100 cycles (523 mAh g−1 at 0.1 A g−1) and shows excellent capacity retention after 500 cycles at large current densities (2 A g−1 and 5 A g−1): 1080 mAh g−1 and 809 mAh g−1 respectively. In addition, in a full-cell system Bi2Se3@SWCNT (1:1) delivers high reversible capacity after 150 cycles (484 mAh g−1) at 0.4 A g−1.

Infrared Light-Emitting Diodes Based on Chirality-Sorted Carbon Nanotube Films.

An important goal in carbon nanotube optoelectronics is to achieve a high-performance near-infrared light source. But there are still many challenges such as the purity of single-walled carbon nanotube (SWCNT) chirality, nonradiative defects, thin-film quality, and device structure design. Here, we realize infrared light-emitting diodes (LEDs) based on chirality-sorted (10, 5) SWCNT network films, which operate at a low bias voltage and emit at a telecom O band of 1290 nm. Asymmetric palladium (Pd) and hafnium (Hf) contacts are used as electrodes for hole and electron injection, respectively. However, the large Schottky barrier at the interface of the SWCNTs and the Hf electrode, primarily resulting from the polymer wrapped on the nanotube surface during the sorting process, leads to inefficient electron injection and thus a low electroluminescence efficiency. We find that the efficiency of electron injection can be improved by the local doping of the nanotubes with dielectric layers of YOX-HfO2, which reduces the Schottky barrier at the SWCNT/Hf interface. Accordingly, the (10, 5) SWCNT film-based LED achieves an external quantum efficiency of larger than 0.05% without any optical coupling structure. With further improvement, we expect that such an infrared light source will have great application potential in the carbon nanotube monolithic optoelectronic integrated system and on-chip optical interconnection, especially in the field of short-distance optical fiber communications and data center.

Cellar automata models for reservoir computing in single-walled carbon nanotube network complexed with polyoxometalate

Cellar automata models for reservoir computing in single-walled carbon nanotube network complexed with polyoxometalate

Электрохимические сенсоры на основе сеток из однослойных углеродных нанотрубок для вольтамперометрического определения аскорбиновой кислоты

Modern highly sensitive and selective sensors are able to determine biologically active substances, which makes this direction one of the most popular areas of analytical chemistry. The study featured the electrochemical properties of new fiber materials based on single-wall carbon nanotubes with prospects of using them in the voltammetry of ascorbic acid. 
 The authors developed a new technology to synthesize films from disordered single-wall carbon nanotubes by chemical vapor deposition. Fibers were produced from a solvent by wet-pulling of single-wall carbon nanotubes networks. Thin films of randomly oriented single-wall carbon nanotube bundles were deposited downstream of a floating aerosol CVD reactor, which included a high temperature furnace with a quartz tube. The synthesis of the single-wall carbon nanotube samples was performed at 825°C. Ethanol served as carbon source while ferrocene was used as catalyst precursor. The single-wall carbon nanotubes were collected on a nitrocellulose filter in the form of films with transmittances of 10% in the middle of the visible wavelength (550 nm). The method was optimized to involve air annealing at 300–320°C and a treatment with strong inorganic acids, i.e., HCl, HNO3 + H2SO4. The voltammetric curves recording included background electrolyte, scan rate, and preconditioning. These parameters were selected experimentally to obtain the maximal sensor response to ascorbic acid content. The anodic peak of ascorbic acid in the phosphate buffer electrolyte (pH 6.86) was observed at a potential of +0.2 V. The current and peak area of ascorbic acid oxidation depended neither on the time nor on the conditioning potential of the sensor. The linear dependences of these parameters on the concentration of ascorbic acid stayed within 50–500 μmol/L (8.8–90 mg/L) at a scan rate of 0.1 mV/s. The single-wall carbon nanotube microsensor had a length of 0.5 cm and an average width of 400 μm. Its sensitivity was two times as high as that of a disk glassy carbon electrode with a diameter of 5 mm. 
 The experimental sensors proved effective in determining ascorbic acid in food products, pharmaceuticals, and biological fluids.

Highly Conductive Robust Carbon Nanotube Networks for Strong Buckypapers and Transparent Electrodes

AbstractWhile individual single‐wall carbon nanotubes (SWCNTs) have remarkable strength and electrical conductivity, SWCNT networks fabricated from dispersions have inferior properties due to nanotube bundling, limiting the potential applications of SWCNT materials. Herein, a common dye molecule (purpurin) is used to exfoliate SWCNTs via noncovalent functionalization and to fabricate SWCNT materials by a simple solution‐based process. The advantageous noncovalent interactions result in efficient exfoliation and metallic SWCNT enrichment, affording SWCNT materials with high mechanical robustness and electrical conductivity. This method is used to prepare mechanically robust SWCNT films and flexible transparent conductive electrodes.

A flexible carbon nanotube film modified with gradient lithiophilic Cu2O/Cu heterojunction for dendrite-free lithium metal anodes

Lithium (Li) metal batteries have been extensively studied for their high energy density, but uncontrolled Li dendrites and severe volume fluctuation significantly limit their commercial applications. To address this issue in Li metal anodes, a flexible self-supporting film was developed by integrating Cu2O/Cu heterojunction with a gradient distribution and a three-dimensional (3D) single-walled carbon nanotube (SWCNT) network. The top-down gradient distribution of Cu2O/Cu effectively reduces the Li+ concentration polarization and conductivity polarization in the vertical direction within the 3D framework, achieving bottom-up deposition of Li inside the framework. Moreover, Mott-Schottky junction between lithiophilic Cu2O and Cu can trigger the built-in electric field (BIEF) at their heterointerfaces, thereby accelerating electron transfer and Li+ migration. Benefiting from the physicochemical bidirectional regulation, the Cu2O/Cu@SWCNT/Li realizes an ultralow voltage polarization of 13 mV and a prolonged cycling stability over 1800 h in a symmetric cell (1 mA cm−2 and 1 mAh cm−2). Additionally, the film shows excellent cycle stability in the Cu2O/Cu@SWCNT-Li//LiFePO4 full cell, providing practical ideas for the subsequent design of lithium metal anodes.

Tuning Electroluminescence from Functionalized SWCNT Networks Further into the Near-Infrared.

Near-infrared electroluminescence from carbon-based emitters, especially in the second biological window (NIR-II) or at telecommunication wavelengths, is difficult to achieve. Single-walled carbon nanotubes (SWCNTs) have been proposed as a possible solution due to their tunable and narrowband emission in the near-infrared region and high charge carrier mobilities. Furthermore, the covalent functionalization of SWCNTs with a controlled number of luminescent sp3 defects leads to even more red-shifted photoluminescence with enhanced quantum yields. Here, we demonstrate that by tailoring the binding configuration of the introduced sp3 defects and hence tuning their optical trap depth, we can generate emission from polymer-sorted (6,5) and (7,5) nanotubes that is mainly located in the telecommunication O-band (1260-1360 nm). Networks of these functionalized nanotubes are integrated in ambipolar, light-emitting field-effect transistors to yield the corresponding narrowband near-infrared electroluminescence. Further investigation of the current- and carrier density-dependent electro- and photoluminescence spectra enables insights into the impact of different sp3 defects on charge transport in networks of functionalized SWCNTs.

Flexible Screen-Printed Amperometric Sensors Functionalized With Spray-Coated Carbon Nanotubes and Electrodeposited Cu Nanoclusters for Nitrate Detection

In this work, we present a novel, sensitive, easy-to-fabricate, flexible amperometric sensor constituted by screen-printed silver (Ag) electrodes functionalized with a copper (Cu) film electrodeposited on top of a spray coated network of single-walled carbon nanotubes (SWCNTs). The Cu/SWCNTs/Ag electrode showed excellent catalytic activity towards the electro-reduction of nitrate ions at neutral pH with a significant increase in cathodic peak currents in comparison with the electrode without SWCNTs (Cu/Ag). The developed Cu/SWCNTs/Ag sensor showed a wide linear detection range from 0.5 μM to 6.0 mM (0.31 mg/l to 372.02 mg/l) with good sensitivity (18.39 μA/mM) and a calculated limit of detection (LOD) of 0.166 nM (10.29 μg/l). It also showed a good selectivity (maximum standard deviation (SD) was 3.25 μA) towards different interfering ions (Fe2+, Na+, Cu2+, SO42-, CH3COO-, Cl-, NO2- and HCO3-), as well as good reproducibility, mechanical durability, time and temperature stability. In real sample analysis (tap and river water), the sensor exhibited good agreement with the compared outcome of high-performance liquid chromatography (HPLC) measurements, proving to be a promising analytical tool for the detection of nitrate in water.

Multifunctional integrated electrochemical sensing platform based on mesoporous silica nanoparticles decorated single-wall carbon nanotubes network for sensitive determination of gallic acid

An efficient ultrasonic-assisted one-pot strategy was applied to prepare the multifunctional nanocomposite of single-wall carbon nanotubes (SWCNT) and mesoporous silica nanoparticles (MSNs). To achieve the sensitive detection of gallic acid (GA), the SWCNT@MSNs/GCE sensor could be fabricated by using the above nanocomposite as electrode sensitizer. For the SWCNT@MSNs nanocomposite, SWCNT with one-dimensional hollow nanostructure could form three-dimensional reinforced carbon conductive network with excellent conductivity property, high specific area, efficient charge transport channels; MSNs with mesoporous structure and large active surface area presented obvious spherical morphology and uniform particle size dispersion, which effectively boosted the accumulation capability of GA on the SWCNT@MSNs/GCE sensor. Moreover, SWCNT with excellent conductivity property could greatly remedy the non-conductivity of MSNs. The synergistic combination of SWCNT and MSNs optimized the electrochemical property of SWCNT@MSNs/GCE sensor for the detection of GA. The SWCNT@MSNs/GCE sensor exhibited good GA electrochemical detection performance (pH = 2.0, linear GA concentration: 0.03–30 μM, limit of detection: 3.806 nM). The relatively low relative standard deviation values can be achieved for the reproducibility, reproducibility and anti-interference measurements. When applied for the detection of GA amount in real tea samples, the satisfactory recoveries of 97.14–101.2% and RSD values of 1.05–4.40 could be obtained at the SWCNT@MSNs/GCE sensor.

Synergistic effect of single wall carbon nanotubes/graphene oxide hybrid nano‐filler on thermal stabilization and tensile strength of polyacrylonitrile copolymer

AbstractThis study reports how hybrid nano‐filler can enhance the tensile strength, electrical properties and thermal stabilization of PAN (polyacrylonitrile) nanocomposite films. The nano‐fillers used are graphene oxide (GO), single‐wall carbon nanotubes (SWCNT), and a hybrid of both. The combination of both nano‐fillers was made by dispersing GO in DMAc (dimethyl acetamide) and then adding SWCNT to the solution. The solution was mixed well using ultrasonication and high‐speed stirring. 1 wt% amount of nano‐filler solutions was added to PAN liquid to make PAN nanocomposite films. The films were tested for mechanical properties, electrical resistivity, thermoxidative stabilization, and thermal stability. The results showed that adding nano‐fillers to PAN significantly improved its tensile strength. GO increased the tensile strength by 42.9% (38.3 MPa), while SWCNT increased it by 57.3% (42.15 MPa). The combination of both (0.5 wt% SWCNT + 0.5 wt% GO) had a remarkable effect, increasing the tensile strength by 96% (52.53 MPa). This was because the combination of both prevented SWCNT from agglomerating together and made it interact better with the PAN, forming a complete network. The combination of both also made the PAN oxidize and stabilize early and efficiently during heating, which made its residual weight increase by ~5.5% more than pristine PAN in TGA. The electrical resistivity and SEM micrograph data correlate with the thermal analysis data, showing that PCG (1 wt% combination) reached the percolation threshold because of the benefits of both GO and SWCNT. The combination of both also showed 95.6% synergy in tensile strength compared to individual nano‐fillers, indicating its potential for efficient reinforcement.Highlights Hybrid filler boosts PAN strength from 26.8 to 52.53 MPa, surpassing PC, PG. TGA: ~5.5 wt% increased residual weight in 1 wt% hybrid‐reinforced PCG composites. Hybrid undergoes GO decomposition, early oxidation and improved stabilization. PCG composite: Enhanced oxidation, improved stabilization via SWCNT network. PC & PCG composites show low volumetric resistivity due to SWCNT network.

Pristine SWCNT Based Cathode Materials for Solid-State Li-Sulfur Batteries

Lithium-Sulfur is a long-studied, but yet to be practically implemented battery chemistry which carries a promise of creating high energy density batteries. It uses cheap and abundant materials, but faces major technological challenges. One of the key challenges is that sulfur as the cathode material has negligible electronic conductivity (5x10-28 S/m), preventing electron exchange in the cathode during battery charge/discharge cycling. The other challenge is the significant (up to 80%) volume changes of sulfur during battery cycling that leads to cracking, delamination, voids formation and loss of electrical contacts, therefore limiting battery durability. To overcome these problems, we have developed a solution-free technology of manufacturing composite self-standing electrodes by in-situ mixing of the aerosolized phases and co-deposition [1]. The electrodes consist of sulfur and catholyte particles imbedded in a 3D network of as grown, pristine single-walled carbon nanotubes. The electrodes are flexible and do not include current collector metal foils or binders. They can be produced up to 1 mm thick, up to 200 mgsulfur/cm2 loading, or 330 mAh/cm2 capacity without the loss of the SWCNT network 3D structure. The macroscopic electrical conductivity of the material increases 30 orders of magnitude compared to that of sulfur, and reaches 102-104 S/m, depending on the SWCNT concentration. The presence of SWCNT network not only solves the electrical conductivity challenge but also durability issue, since flexible/stretchable SWCNT network accommodates the volume change of the sulfur active particles without disruption of the cathode integrity. The electrodes fabricated by this method are being studied as perspective cathodes for solid-state LiS batteries. A. Kuznetsov, S. Mohanty, E. Pigos, G. Chen, W. Cai, A.R. Harutyunyan, High energy density flexible and ecofriendly lithium-ion smart battery. Energy Storage Materials, 2023 (54) 266-275, ISSN 2405-8297, doi.org/10.1016/j.ensm.2022.10.023

(Invited) Engineering Single Wall Carbon Nanotubes for Sub-Cellular Drug Delivery

Single wall carbon nanotubes (SWCNTs) have been rigorously studied and engineered for a myriad of applications including drug delivery due to their unique, desirable properties. Since SWCNTs bundle in aqueous media and the bundling substantially diminishes their desirable properties along with inducing cytotoxicity, strategies to disperse individually SWCNTs with therapeutic molecules and biologic excipients have been heavily investigated. However, a handful of studies has been performed to understand the interactions between therapeutic molecules and excipients with SWCNT interface as well as the mechanism of intracellular release for therapeutic effects. Additionally, little attention has been paid to how cell type and cell metabolic activity level influence internalization of SWCNTs with different lengths. In this talk, I will discuss cell type, cell metabolic activity, and SWCNT length dependent cellular processing of SWCNTs dispersed with diverse biocompatible dispersing agents. Our results demonstrate that proper choice of dispersing agent can allow for interaction with F-actin, accumulation in the endoplasmic reticulum for eventual expulsion, or accumulation in cell nucleus. Further, macrophages with relatively high cell metabolic activity level compared to other cell types such as fibroblasts have shown to internalize significantly higher amount of SWCNTs per cell. The total mass of SWCNTs internalized per cell increases with a decrease in SWCNT length. Lastly, I will discuss our recent effort to create a ternary complex of SWCNTs, drug, and protein for intracellular delivery and release of model drugs. To overcome the limitation of the existing methods being only plausible for model drugs that are soluble in aqueous solutions, we developed a facile schema to assemble stepwise various combinations of therapeutic molecules and excipients on SWCNTs in different solvents using a preformed SWCNT network. These ternary complexes allow dialing in delivery of therapeutic molecules and excipients to achieve desired cell viability reduction. These findings allow for the development of new SWCNT-based biological applications as they establish important parameters of biomolecule adsorption on SWCNTs, SWCNT internalization and subcellular processing, which are crucial for applications ranging from drug delivery to cell type-specific modulation.

Stress-Strain and Resistance-Strain Hysteresis in Single-Wall Carbon Nanotube Films for Stretchable Battery Electrodes

The need to protect the vulnerable and limited resources that are naturally available while meeting the growing energy demand of the world makes the sustainable development of renewable energy of paramount importance. To address these needs, a new type of battery electrode has been developed at Honda Research Institute (HRI), based on free-standing single-wall carbon nanotube (SWNT) films containing active battery materials as dispersed nanoparticles. The SWNT films provide both mechanical support and electrical conductivity, removing the need for metal electrodes (increasing the energy density of the battery) and binder materials (making the process environmentally friendly).Under cyclic strain, the SWNT-based electrodes show hysteretic behaviors in both stress-strain and electrical resistance-strain relations. The electrical resistance-strain behavior shows a different trend from the previously observed behavior on 2D SWNT films (on elastic substrate). We hypothesize that this change can be attributed to the differences in the SWNT network structures in the 2D and 3D films. To understand the microscopic origin of the hysteresis, we performed coarse-grained molecular statics (CGMS) simulations of the SWNT film. The simulations show that the intrinsic Van der Waals interaction between SWNTs is responsible for the observed robust mechanical properties of the electrodes. In addition, our study also reveals that the sparsity of the 3D morphology results in the current being carried across the simulation box only by a few paths. As a consequence, the resistance hysteresis is governed entirely by the change in the power-carrying capacity of the network due to the breaking and formation of contacts between the SWNTs during loading-unloading. The qualitative nature of the resistance-strain hysteresis can thus be attributed to the rapid formation of inter-nanotube contacts, as the nanotube bundles (elongated by initial loading) buckle during unloading.

Geometrical and chemical effects on the electrochemistry of single-wall carbon nanotube (SWCNT) network electrodes

Single-wall carbon nanotube (SWCNT) network is a promising electrode material for bio detection. Unfortunately, the associations between their physical as well as chemical properties and observed electrochemical performance are not known. This hinders any systematic optimization of the network properties towards specific analytes. Here we present a consistent physicochemical and electrochemical characterization of differently treated SWCNT networks. The results unambiguously show that (i) even if the electrochemical properties of different electrodes are practically identical when assessed by surface insensitive outer sphere redox (OSR) probes their behavior with inner sphere redox (ISR) probes can be drastically different. Further, (ii) the choice of the modification method (structural, chemical, electrochemical) heavily depends on nature of the target analyte, which are typically ISR probes. Although, (iii) chemical changes in the carbon phase appeared to be minor, effects of different treatments on oxidation states of Fe appeared to have a strong effect on the electrochemical performance of the networks in the case of ISR probes.