Dopamine Measurement Using Engineered CNT-CQD-Polymer Coatings on Pt Microelectrodes.

This study aims to develop a microelectrode array-based neural probe that can record dopamine activity with high stability and sensitivity. To mimic the high stability of the gold standard method (carbon fiber electrodes), the microfabricated platinum microelectrode is coated with carbon-based nanomaterials. Carboxyl-functionalized multi-walled carbon nanotubes (COOH-MWCNTs) and carbon quantum dots (CQDs) were selected for this purpose, while a conductive polymer like poly (3-4-ethylene dioxythiophene) (PEDOT) or polypyrrole (PPy) serves as a stable interface between the platinum of the electrode and the carbon-based nanomaterials through a co-electrodeposition process. Based on our comparison between different conducting polymers and the addition of CQD, the CNT-CQD-PPy modified microelectrode outperforms its counterparts: CNT-CQD-PEDOT, CNT-PPy, CNT-PEDOT, and bare Pt microelectrode. The CNT-CQD-PPy modified microelectrode has a higher conductivity, stability, and sensitivity while achieving a remarkable limit of detection (LOD) of 35.20 ± 0.77 nM. Using fast-scan cyclic voltammetry (FSCV), these modified electrodes successfully measured dopamine's redox peaks while exhibiting consistent and reliable responses over extensive use. This electrode modification not only paves the way for real-time, precise dopamine sensing using microfabricated electrodes but also offers a novel electrochemical sensor for in vivo studies of neural network dynamics and neurological disorders.

Multiscale Carbon Fibre-Carbon Nanotube Composites of Poly(Vinyl Chloride)-An Evaluation of Their Properties and Structure.

To date, there has been limited information in the literature on the application of carbon fibre-carbon nanotube systems for the modification of poly(vinyl chloride) (PVC) matrixes by micro- and nanometric fillers and an evaluation of the properties of the unique materials produced. This paper presents the results of newly designed unique multiscale composites. The advantages of the simultaneous use of carbon fibres (CFs) and carbon nanotubes (CNTs) in PVC modification are discussed. To increase the dispersibility of the nanofiller, CFs together with nanotubes were subjected to a sonication process. The resulting material was introduced into PVC blends, which were processed by extrusion. The ratio of components in the hybrid filler with CF_CNT was 20:1, and its proportion in the PVC matrix was 1, 5, and 10 wt.%, respectively. Comparatively, PVC composites modified only with carbon fibres were obtained. The structure, thermal, electrical, and mechanical properties and swelling resistance of the composites were studied. The study showed a favourable homogeneous dispersion of nanotubes in the PVC matrix. This enabled effective modification of the structure at the nanometric level and the formation of an interpenetrating network of well-dispersed hybrid filler, as evidenced by a decrease in volume resistivity and improvement in swelling resistance, as well as an increase in glass transition temperature in the case of PVC/CF_CNT composites.

Shift of switching threshold in low-dimensional semiconductor-based complementary inverters via inkjet printing.

MoS2crystals grown by chemical vapor deposition are suited for realization of practical 2D semiconductor-based electronics. In order to construct complementary circuits with n-type MoS2, another p-type semiconductor, whose performance can be adjusted corresponding to that of MoS2in the limited chip area, has to be sought. Herein, we present a method for tuning switching threshold voltages of complementary inverters simply via inkjet printing without changing their channel dimensions. Random networks of inkjet printed single-walled carbon nanotubes are formed as p-channels beside MoS2, and their density and thickness are controlled by varying the number of printed layers. As a result, p-type transistor characteristics as well as inverter characteristics are facilely tuned only by varying the number of printed layers.

Schemes for Single Electron Transistor Based on Double Quantum Dot Islands Utilizing a Graphene Nanoscroll, Carbon Nanotube and Fullerene.

The single electron transistor (SET) is a nanoscale switching device with a simple equivalent circuit. It can work very fast as it is based on the tunneling of single electrons. Its nanostructure contains a quantum dot island whose material impacts on the device operation. Carbon allotropes such as fullerene (C60), carbon nanotubes (CNTs) and graphene nanoscrolls (GNSs) can be utilized as the quantum dot island in SETs. In this study, multiple quantum dot islands such as GNS-CNT and GNS-C60 are utilized in SET devices. The currents of two counterpart devices are modeled and analyzed. The impacts of important parameters such as temperature and applied gate voltage on the current of two SETs are investigated using proposed mathematical models. Moreover, the impacts of CNT length, fullerene diameter, GNS length, and GNS spiral length and number of turns on the SET's current are explored. Additionally, the Coulomb blockade ranges (CB) of the two SETs are compared. The results reveal that the GNS-CNT SET has a lower Coulomb blockade range and a higher current than the GNS-C60 SET. Their charge stability diagrams indicate that the GNS-CNT SET has smaller Coulomb diamond areas, zero-current regions, and zero-conductance regions than the GNS-C60 SET.

Understanding Carbon Nanotube-Based Ionic Diodes: Design and Mechanism.

The rectification of ion transport through biological ion channels has attracted much attention and inspired the thriving invention and applications of ionic diodes. However, the development of high-performance ionic diodes is still challenging, and the working mechanisms of ionic diodes constructed by 1D ionic nanochannels have not been fully understood. This work reports the systematic investigation of the design and mechanism of a new type of ionic diode constructed from horizontally aligned multi-walled carbon nanotubes (MWCNTs) with oppositely charged polyelectrolytes decorated at their two entrances. The major design and working parameters of the MWCNT-based ionic diode, including the ion channel size, the driven voltage, the properties of working fluids, and the quantity and length of charge modification, are extensively investigated through numerical simulations and/or experiments. An optimized ionic current rectification (ICR) ratio of 1481.5 is experimentally achieved on the MWCNT-based ionic diode. These results promise potential applications of the MWCNT-based ionic diode in biosensing and biocomputing. As a proof-of-concept, DNA detection and HIV-1 diagnosis is demonstrated on the ionic diode. This work provides a comprehensive understanding of the working principle of the MWCNT-based ionic diodes and will allow rational device design and optimization.

Evaluation of reconstruction algorithms for a stationary digital breast tomosynthesis system using a carbon nanotube X-ray source array.

Breast cancer is the most frequently diagnosed cancer in women worldwide. Digital breast tomosynthesis (DBT), which is based on limited-angle tomography, was developed to solve tissue overlapping problems associated with traditional breast mammography. However, due to the problems associated with tube movement during the process of data acquisition, stationary DBT (s-DBT) was developed to allow the X-ray source array to stay stationary during the DBT scanning process. In this work, we evaluate four widely used and investigated DBT image reconstruction algorithms, including the commercial Feldkamp-Davis-Kress algorithm (FBP), the simultaneous iterative reconstruction technique (SIRT), the simultaneous algebraic reconstruction technique (SART) and the total variation regularized SART (SART-TV) for an s-DBT imaging system that we set up in our own laboratory for studies using a semi-elliptical digital phantom and a rubber breast phantom to determine the most superior algorithm for s-DBT image reconstruction among the four algorithms. Several quantitative indexes for image quality assessment, including the peak signal-noise ratio (PSNR), the root mean square error (RMSE) and the structural similarity (SSIM), are used to determine the best algorithm for the imaging system that we set up. Image resolutions are measured via the calculation of the contrast-to-noise ratio (CNR) and artefact spread function (ASF). The experimental results show that the SART-TV algorithm gives reconstructed images with the highest PSNR and SSIM values and the lowest RMSE values in terms of image accuracy and similarity, along with the highest CNR values calculated for the selected features and the best ASF curves in terms of image resolution in the horizontal and vertical directions. Thus, the SART-TV algorithm is proven to be the best algorithm for use in s-DBT image reconstruction for the specific imaging task in our study.

Clay based nanocomposites for removal of heavy metals from water: A review.

The exponential increment in world population, recent industrialization, civilization, agricultural and household activities leads to greater levels of water pollution in terms of organic and inorganic contaminants. However, numerous workers have done research for the removal of these pollutants and various types of clays and/or modified clays have been extensively used for this purpose. But all identified adsorbent materials are not able to remove pollutants after certain concentration and sometimes these contaminants are left as such in environment which may create other environmental issues. This paper presents comprehensive information for the adsorption of heavy metal ions from water and waste water using various nanostructured adsorbents such as different clay minerals (kaolinite, montmorillonite) and clay (bentonite), carbon nanotube and nanocomposites. In addition to this, the efficiency of developed materials for the removal of heavy metals is also discussed in details along with comparison of their adsorption efficiencies, pH and change in specific surface area, initial metal ion concentration and contact time. This paper also states the future directions which could be followed to challenge the situation of removal of traces of heavy metals from water, hence protecting water bodies from high pollution load.

Real-Time Monitoring of a Botulinum Neurotoxin Using All-Carbon Nanotube-Based Field-Effect Transistor Devices.

The possibility of exposure to botulinum neurotoxin (BoNT), a powerful and potential bioterrorism agent, is considered to be ever increasing. The current gold-standard assay, live-mouse lethality, exhibits high sensitivity but has limitations including long assay times, whereas other assays evince rapidity but lack factors such as real-time monitoring or portability. In this study, we aimed to devise a novel detection system that could detect BoNT at below-nanomolar concentrations in the form of a stretchable biosensor. We used a field-effect transistor with a p-type channel and electrodes, along with a channel comprising aligned carbon nanotube layers to detect the type E light chain of BoNT (BoNT/E-Lc). The detection of BoNT/E-Lc entailed observing the cleavage of a unique peptide and the specific bonding between BoNT/E-Lc and antibody BoNT/E-Lc (Anti-BoNT/E-Lc). The unique peptide was cleaved by 60 pM BoNT/E-Lc; notably, 52 fM BoNT/E-Lc was detected within 1 min in the device with the antibody in the bent state. These results demonstrated that an all-carbon nanotube-based device (all-CNT-based device) could be produced without a complicated fabrication process and could be used as a biosensor with high sensitivity, suggesting its potential development as a wearable BoNT biosensor.

Reversible Tuning of Individual Carbon Nanotube Mechanical Properties via Defect Engineering.

The structural defects that inevitably exist in real-world carbon nanotubes (CNTs) are generally considered undesirable because they break the structural perfection and may result in drastically degraded CNT properties. On the other hand, the deliberate defect introduction can provide a possibility to tailor the tube mechanical properties. Herein, we present a fully controllable technique to handle defects by using in situ transmission electron microscopy (TEM). Young's modulus, quality factor of the resonation and tensile strength of CNTs can be controllably, reversibly, and repeatedly tuned. Parallel high-resolution visualizing of structural defects suggests that the property tuning cycles are primarily attributed to the reversible conversion of defects at the atomic scale: the defects are created in the form of vacancies and interstitials under electron irradiation, and they vanish through the recombination via current-induced annealing. For applications, such as reversible frequency-tuned CNT resonators, this defect-engineering technique is demonstrated to be uniquely precise; the frequency may be tuned with 0.1%/min accuracy, improved by 1 order of magnitude compared with the existing approaches. We believe that these results will be highly valuable in a variety of property-tunable CNT-based composites and devices.

Prelithiation Activates Li(Ni0.5Mn0.3Co0.2)O2 for High Capacity and Excellent Cycling Stability.

Transition metal oxide materials Li(NixMnyCoz)O2 (NMC) based on layered structures are expected to replace LiFePO4 in automotive Li-ion batteries because of their higher specific capacity and operating potential. However, the actual usable capacity is much lower than the promised theoretical value [Uchaker, E.; Cao, G. Nano Today 2014, 9, 499-524; Tarascon, J.-M.; Armand, M. Nature 2001, 414, 359-367], in addition to the often poor cycling performance and the first-cycle Coulombic efficiency, for which Mn(II)-dissolution, its immobilization in solid electrolyte interface (SEI), oxidation of electrolytes by Ni, and other parasitic process thereat have been held responsible [Zhan, C., et al. Nat. Commun. 2013, 4, 2437; Wang, L., et al. J. Solid State Electrochem. 2009, 13, 1157-1164; Lin, F., et al. Nat. Commun. 2014, 5, 4529]. Previously, we reported a composite Li(Ni0.5Mn0.3Co0.2)O2 (NMC532) depolarized by the embedded carbon nanotube (CNT) and achieved capacity close to the theoretical limit [Wu, Z., et al. Nano. Lett. 2014, 14, 4700-4706]; unfortunately, this high capacity failed to be maintained in long-term cycling due to the degrading contacts between the active ingredient and CNT network. On the basis of that NMC532/CNT composite, the present work proposes a unique "prelithiation process", which brought the cathode to low potentials before regular cycling and led to an interphase that is normally formed only on anode surfaces. The complete coverage of cathode surface by this ∼40 nm thick interphase effectively prevented Mn(II) dissolution and minimized the side reactions of Ni, Co, and Mn at the NMC interface during the subsequent cycling process. More importantly, such a "prelithiation" process activated a structure containing two Li layers near the surface of NMC532 particles, as verified by XRD and first principle calculation. Hence, a new cathode material of both high capacity with depolarized structure and excellent cycling performance was generated. This new structure can be incorporated in essentially all the NMC-based layered cathode materials, providing us with an effective tool to tailor-design future new cathode materials for lithium batteries.

Morse Code Recognition Based on a Flexible Tactile Sensor with Carbon Nanotube/Polyurethane Sponge Material by the Long Short-Term Memory Model.

Morse code recognition plays a very important role in the application of human-machine interaction. In this paper, based on the carbon nanotube (CNT) and polyurethane sponge (PUS) composite material, a flexible tactile CNT/PUS sensor with great piezoresistive characteristic is developed for detecting Morse code precisely. Thirty-six types of Morse code, including 26 letters (A-Z) and 10 numbers (0-9), are applied to the sensor. Each Morse code was repeated 60 times, and 2160 (36 × 60) groups of voltage time-sequential signals were collected to construct the dataset. Then, smoothing and normalization methods are used to preprocess and optimize the raw data. Based on that, the long short-term memory (LSTM) model with excellent feature extraction and self-adaptive ability is constructed to precisely recognize different types of Morse code detected by the sensor. The recognition accuracies of the 10-number Morse code, the 26-letter Morse code, and the whole 36-type Morse code are 99.17%, 95.37%, and 93.98%, respectively. Meanwhile, the Gated Recurrent Unit (GRU), Support Vector Machine (SVM), Multi-Layer Perceptron (MLP), and Random Forest (RF) models are built to distinguish the 36-type Morse code (letters of A-Z and numbers of 0-9) based on the same dataset and achieve the accuracies of 91.37%, 88.88%, 87.04%, and 90.97%, respectively, which are all lower than the accuracy of 93.98% based on the LSTM model. All the experimental results show that the CNT/PUS sensor can detect the Morse code's tactile feature precisely, and the LSTM model has a very efficient property in recognizing Morse code detected by the CNT/PUS sensor.

Engineering biomimetic scaffolds for bone regeneration: Chitosan/alginate/polyvinyl alcohol-based double-network hydrogels with carbon nanomaterials.

In this study, new types of hybrid double-network (DN) hydrogels composed of polyvinyl alcohol (PVA), chitosan (CH), and sodium alginate (SA) are introduced, with the hypothesis that this combination and incorporating multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) will enhance osteogenetic differentiation and the structural and mechanical properties of scaffolds for bone tissue engineering applications. Initially, the impact of varying mass ratios of the PVA/CH/SA mixture on mechanical properties, swelling ratio, and degradability was examined. Based on this investigation, a mass ratio of 4:6:6 was determined to be optimal. At this ratio, the hydrogel demonstrated a Young's modulus of 47.5 ± 5 kPa, a swelling ratio of 680 ± 6 % after 3 h, and a degradation rate of 46.5 ± 5 % after 40 days. In the next phase, following the determination of the optimal mass ratio, CNTs and GNPs were incorporated into the 4:6:6 composite resulting in a significant enhancement in the electrical conductivity and stiffness of the scaffolds. The introduction of CNTs led to a notable increase of 36 % in the viability of MG63 osteoblast cells. Additionally, the inhibition zone test revealed that GNPs and CNTs increased the diameter of the inhibition zone by 49.6 % and 52.6 %, respectively.

Performance Projection of Vacuum Gate Dielectric Doping-Free Carbon Nanoribbon/Nanotube Field-Effect Transistors for Radiation-Immune Nanoelectronics.

This paper investigates the performance of vacuum gate dielectric doping-free carbon nanotube/nanoribbon field-effect transistors (VGD-DL CNT/GNRFETs) via computational analysis employing a quantum simulation approach. The methodology integrates the self-consistent solution of the Poisson solver with the mode space non-equilibrium Green's function (NEGF) in the ballistic limit. Adopting the vacuum gate dielectric (VGD) paradigm ensures radiation-hardened functionality while avoiding radiation-induced trapped charge mechanisms, while the doping-free paradigm facilitates fabrication flexibility by avoiding the realization of a sharp doping gradient in the nanoscale regime. Electrostatic doping of the nanodevices is achieved via source and drain doping gates. The simulations encompass MOSFET and tunnel FET (TFET) modes. The numerical investigation comprehensively examines potential distribution, transfer characteristics, subthreshold swing, leakage current, on-state current, current ratio, and scaling capability. Results demonstrate the robustness of vacuum nanodevices for high-performance, radiation-hardened switching applications. Furthermore, a proposal for extrinsic enhancement via doping gate voltage adjustment to optimize band diagrams and improve switching performance at ultra-scaled regimes is successfully presented. These findings underscore the potential of vacuum gate dielectric carbon-based nanotransistors for ultrascaled, high-performance, energy-efficient, and radiation-immune nanoelectronics.

Flexible Bifunctional Electrode for Alkaline Water Splitting with Long-Term Stability.

Progress in electrochemical water-splitting devices as future renewable and clean energy systems requires the development of electrodes composed of efficient and earth-abundant bifunctional electrocatalysts. This study reveals a novel flexible and bifunctional electrode (NiO@CNTR) by hybridizing macroscopically assembled carbon nanotube ribbons (CNTRs) and atmospheric plasma-synthesized NiO quantum dots (QDs) with varied loadings to demonstrate bifunctional electrocatalytic activity for stable and efficient overall water-splitting (OWS) applications. Comparative studies on the effect of different electrolytes, e.g., acid and alkaline, reveal a strong preference for alkaline electrolytes for the developed NiO@CNTR electrode, suggesting its bifunctionality for both HER and OER activities. Our proposed NiO@CNTR electrode demonstrates significantly enhanced overall catalytic performance in a two-electrode alkaline electrolyzer cell configuration by assembling the same electrode materials as both the anode and the cathode, with a remarkable long-standing stability retaining ∼100% of the initial current after a 100 h long OWS run, which is attributed to the "synergistic coupling" between NiO QD catalysts and the CNTR matrix. Interestingly, the developed electrode exhibits a cell potential (E10) of only 1.81 V with significantly low NiO QD loading (83 µg/cm2) compared to other catalyst loading values reported in the literature. This study demonstrates a potential class of carbon-based electrodes with single-metal-based bifunctional catalysts that opens up a cost-effective and large-scale pathway for further development of catalysts and their loading engineering suitable for alkaline-based OWS applications and green hydrogen generation.

Strategies for enhancing the analytical performance of nanomaterial-based sensors.

We provide a state-of-the-art review of the main strategies for the enhancement of analytical performance of sensors using nanomaterials, particularly nanowires and carbon-based materials. We emphasize the way to overcome the problem of device-to-device variation. We discuss the study of the influence of nanomaterial characteristics, sensor dimensions and operational conditions on sensing performance, and the application of appropriate calibration models.

Transition of Carbon Nanotube Sheets from Hydrophobicity to Hydrophilicity by Facile Electrochemical Wetting.

The present study delves into the transformative effects of electrochemical oxidation on the hydrophobic-to-hydrophilic transition of carbon nanotube (CNT) sheets. The paper elucidates the inherent advantages of CNT sheets, such as high electrical conductivity and mechanical strength, and contrasts them with the limitations posed by their hydrophobic nature. A comprehensive investigation is conducted to demonstrate the efficacy of electrochemical oxidation treatment in modifying the surface properties of CNT sheets, thereby making them hydrophilic. The study reveals that the treatment not only is cost-effective and time-efficient compared to traditional plasma treatment methods but also results in a significant decrease in water contact angle. Mechanistic insights into the hydrophilic transition are provided, emphasizing the role of oxygen-containing functional groups introduced during the electrochemical oxidation process.

CNT and Graphene-Based Transistor Biosensors for Cancer Detection: A Review.

An essential aspect of successful cancer diagnosis is the identification of malignant tumors during the early stages of development, as this can significantly diminish patient mortality rates and increase their chances of survival. This task is facilitated by cancer biomarkers, which play a crucial role in determining the stage of cancer cells, monitoring their growth, and evaluating the success of treatment. However, conventional cancer detection methods involve several intricate steps, such as time-consuming nucleic acid amplification, target detection, and a complex treatment process that may not be appropriate for rapid screening. Biosensors are emerging as promising diagnostic tools for detecting cancer, and carbon nanotube (CNT)- and graphene-based transistor biosensors have shown great potential due to their unique electrical and mechanical properties. These biosensors have high sensitivity and selectivity, allowing for the rapid detection of cancer biomarkers at low concentrations. This review article discusses recent advances in the development of CNT- and graphene-based transistor biosensors for cancer detection.

Lamellar Wood Sponge with Vertically Aligned Channels for Highly Efficient and Salt-Resistant Solar Desalination.

Solar-assisted interfacial evaporation is a promising approach for purifying and desalinating water. As a sustainable biomass material, wood has attracted increasing interest as an innovative substrate for solar desalination, owing to its intrinsic porous structure, high hydrophilicity, and low thermal conductivity. However, developing wood-based solar evaporators with high evaporation rates and excellent salt resistance still remains a significant challenge, owing to the absence of large pores with high interconnectivity in natural wood. Herein, by converting the honeycombed structure of natural wood into a lamellar architecture via structural engineering, we develop a flexible wood sponge with vertically aligned channels for efficient and salt-resistant solar desalination after surface coating with carbon nanotubes (CNTs). The special lamellar structure with an interlayer distance of 50-300 µm provides the wood sponge with faster water transport, lower thermal conductivity, and water evaporation enthalpy, thus achieving higher evaporation performances in comparison with the cellular structure of natural wood. Noteworthy, the vertically aligned channels of the wood sponge facilitate sufficient fluid convection and diffusion and enable efficient salt exchanges between the heating interface and the underlying bulk water, thus preventing salt accumulation on the surface. Benefiting from the distinctive lamellar structure, the developed wood-sponge evaporator exhibits exceptional salt resistance even in a hypersaline brine (20 wt %) during continuous 7-day desalination under 1 sun irradiation, with a high evaporation rate (1.38-1.43 kg m-2 h-1), outperforming most previously reported wood-based evaporators. The lamellar wood sponge may provide a promising strategy for desalinating high-salinity brines in an efficient manner.

Long-Lasting Electret Melt-Blown Nonwoven Functional Filters Made of Organic/Inorganixc Macromolecular Micron Materials: Manufacturing Techniques and Property Evaluations.

Melt-blown nonwoven fabrics for filtration are usually manufactured using polypropylene, but after a certain time period the middle layer of the mask may have a reduced effect on adsorbing particles and may not be easily stored. Adding electret materials not only increases storage time, but also shows in this study that the addition of electret can improve filtration efficiency. Therefore, this experiment uses a melt-blown method to prepare a nonwoven layer, and adds MMT, CNT, and TiO2 electret materials to it for experiments. Polypropylene (PP) chip, montmorillonite (MMT) and titanium dioxide (TiO2) powders, and carbon nanotube (CNT) are blended and made into compound masterbatch pellets using a single-screw extruder. The resulting compound pellets thus contain different combinations of PP, MMT, TiO2, and CNT. Next, a hot pressor is used to make the compound chips into a high-poly film, which is then measured with differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The optimal parameters are yielded and employed to form the PP/MMT/TiO2 nonwoven fabrics and PP/MMT/CNT nonwoven fabrics. The basis weight, thickness, diameter, pore size, fiber covering ratio, air permeability, and tensile property of different nonwoven fabrics are evaluated in order to have the optimal group of PP-based melt-blown nonwoven fabrics. According to the results of DSC and FTIR measurements, PP and MMT, CNT, and TiO2 are completely mixed, and the melting temperature (Tm), crystallization temperature (Tc) and endotherm area are changed accordingly. The difference in enthalpy of melting changes the crystallization of PP pellets, which in turn changes the fibers. Moreover, the Fourier transform infrared (FTIR) spectroscopy results substantiate that PP pellets are well blended with CNT and MMT, according to the comparisons of characteristic peaks. Finally, the scanning electron microscopy (SEM) observation suggests that with a spinning die temperature of 240 °C and a spinning die pressure lower than 0.01 MPa, the compound pellets can be successfully formed into melt-blown nonwoven fabrics with a 10-micrometer diameter. The proposed melt-blown nonwoven fabrics can be processed with electret to form long-lasting electret melt-blown nonwoven filters.

The hydration of Li+ and Mg2+ in subnano carbon nanotubes using a multiscale theoretical approach.

The separation of brines with high Mg/Li mass ratios is a huge challenge. To provide a theoretical basis for the design of separation materials, the hydration of Li+ and Mg2+ in confinement using carbon nanotubes (CNTs) as the 1-D nanopore model was investigated using a multiscale theoretical approach. According to the analysis of the first coordination layer of cations, we determined that the coordination shells of two cations exist inside CNTs, while the second coordination shells of the cations are unstable. Moreover, the results of the structure analysis indicate that the hydration layer of Li+ is not complete in CNTs with diameters of 0.73, 0.87, and 1.00 nm. However, this does not occur in the 0.60 nm CNT, which is explained by the formation of contact ion pairs (CIP) between Li+ and Cl- that go through a unstable solvent-shared ion pair [Li(H2O)4]+, and this research was further extended by 400 ns in the 0.60 nm CNT to address the aforementioned results. However, the hydration layer of Mg2+ is complete and not sensitive to the diameter of CNTs using molecular dynamics simulation and an ab initio molecular dynamics (AIMD) method. Furthermore, the results of the orientation distribution of Li+ and Mg2+ indicate that the water molecules around Mg2+ are more ordered than water molecules around Li+ in the CNTs and are more analogous to the bulk solution. We conclude that it is energetically unfavorable to confine Li+ inside the 0.60-nm diameter CNT, while it is favorable for confining Li+ inside the other four CNTs and Mg2+ in all CNTs, which is driven by the strong electrostatic interaction between cations and Cl-. In addition, the interaction between cations and water molecules in the five CNTs was also analyzed from the non-covalent interaction (NCI) perspective by AIMD.