Unzipping Of Carbon Nanotubes Research Articles

Strongly toughened heat‐resistant cyanate ester resin‐based coatings doped by Tb3+‐complex anchored‐uCNTs with green fluorescent properties

AbstractThermally stable polymeric coatings are widely used for metal protection at high temperatures, but their brittle weakness makes them unavailable to durable environment. To overcome that, we report properties of cyanate ester resin (CER) coating doped with unzipped carbon nanotubes (uCNTs) loaded with terbium complex (TBP) as nanofiller. The performance of the coating showed that the bending flexibility, adhesion, and impact resistance of the doped coatings was significantly improved. The cylinder bending test showed that the minimal bending diameter of CER doped with TBP‐uCNTs coating reached 6 mm without failure, which represents a significant improvement compared to the pure CER coating (18 mm). Surprisingly, the impact resistance reached the highest value of 50 cm without any failure of the coating. X‐ray diffraction, Fourier transform infrared spectroscopy, Raman, x‐ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy studies of CNTs, uCNTS, TBP‐uCNTs, and properties of CER indicate that formation of CER/TBP‐uCNTs composite is supported by a chemical reaction between hydroxyl groups of TBP‐uCNTs and the cyanate groups of CER resulting in fabrication of a solid cross‐linked structure. The thermal decomposition temperature of the coating increases from 409°C for pure CER to 453°C for CER/TBP‐uCNTs. The fluorescence spectra show that CER/TBP‐uCNTs exhibits strong luminescence at 550 nm.

On-Surface Synthesis of Open-Shell Nanographenes through the π-Extension of Dibenzo[Hi,St]Ovalene

Graphene nanostructures are attracting attentions for their intriguing optical, electronic, and magnetic properties that are critically dependent on their chemical structures. Whereas it is challenging to obtain atomically precise structures by typical top-down fabrication methods, such as lithographic patterning of graphene and unzipping of carbon nanotubes, bottom-up synthesis enables the preparation of molecular nanographenes and graphene nanoribbons (GNRs) with pre-designed structures. In addition to the solution synthesis based on the methods of synthetic organic chemistry, such graphene nanostructures can also be synthesized on metal surfaces under ultrahigh vacuum conditions and directly visualized by atomic resolution scanning probe microscopy (SPM) [1]. Using carefully designed and solution-synthesized molecular precursors, this on-surface synthesis method can provide various nanographenes, including the structures that are highly unstable under ambient conditions. We have previously developed the solution synthesis of dibenzo[hi,st]ovalene (DBOV) with strong red fluorescence [2], and achieved its π-extension to circumpyrene [3]. Following the successful synthesis of rhombus-shaped nanographenes with four zigzag edges, showing a closed-shell or an open-shell depending on the size [4], we functionalized DBOV and circumpyrene with two 2,6-dimethylphenyl groups for their on-surface π-extension to unprecedented zigzag-edged nanographenes. The resulting structures were clearly visualized by scanning tunneling microcopy and their open-shell characters were indicated by theoretical and experimental investigations, revealing large magnetic exchange couplings of up to 190 meV [5]. We have more recently also achieved further π-extension of these open-shell nanographenes on surface and obtained initial results for their polymerization.[1] Chen, Z.; Narita, A.; Müllen, K.; Adv. Mater. 2020, 32, 2001893.[2] Paternò, G. M.; Chen, Q.; Wang, X.-Y.; Liu, J.; Motti, S. G.; Petrozza, A.; Feng, X.; Lanzani, G.; Müllen, K.; Narita, A.; Scotognella, F., Angew. Chem. Int. Ed. 2017, 56, 6753–6757.[3] Chen, Q.; Schollmeyer, D.; Müllen, K.; Narita, A., J. Am. Chem. Soc. 2019, 141, 19994–19999.[4] Mishra, S.; Yao, X.; Chen, Q.; Eimre, K.; Gröning, O.; Ortiz, R.; Di Giovannantonio, M.; Sancho-García, J. C.; Fernández-Rossier, J.; Pignedoli, C. A.; Müllen, K.; Ruffieux, P.; Narita, A.; Fasel, R.; Nat. Chem. 2021, 13, 581.[5] Biswas, K.; Soler, D.; Mishra, S.; Chen, Q.; Yao, X.; Sánchez-Grande, A.; Eimre, K.; Mutombo, P.; Martín-Fuentes, C.; Lauwaet, K.; Gallego, J. M.; Ruffieux, P.; Pignedoli, C. A.; Müllen, K.; Miranda, R.; Urgel, J. I.; Narita, A.; Fasel, R.; Jelínek, P.; Écija, D. J. Am. Chem. Soc. 2023, 145, 2968–2974.

Synthesis of PVA–MWCNTs–UMCNOs–starch crosslinked nanocomposite biodegradable films for the removal of methylene blue and Congo red dyes from wastewater

AbstractPlastic waste and wastewater are indeed significant environmental issues that have wide‐ranging impacts on ecosystems, human health, and the economy. This study outlines the synthesis of biodegradable polyvinyl alcohol (PVA)–starch polymeric films incorporating multiwalled carbon nanotubes (MWCNTs) derived from plastic waste and unzipped carbon nanotubes oxides (UMCNOs) as co‐filled nanomaterials. These films were formulated based on data generated using a mixture design method in Design Expert 13 software, resulting in the synthesis of 19 films utilizing five types of PVA–starch polymer solutions (Types A–E). The synthesized films underwent characterization to study their surface morphology via scanning electron microscope and Fourier transform infrared spectroscopy analysis. Subsequently, the films were individually subjected to vacuum filtration, through which cationic dyes such as methylene blue (MB) and anionic dye Congo red (CR) were passed in batches. The highest removal efficiency of 96.43% for MB dye was achieved, accompanied by an exceptionally high flux of 3146.78 LMH. Similarly, the maximum removal of 88.08% for CR was observed with a flux of 1512.66 LMH. The renewable active sites mechanism resulted in increased dye removal with every cycle. Results indicated efficient reusability, particularly when washed with ethanol–water solution.

Structural model of oxidatively unzipped narrow single-walled carbon nanotubes

In this study, we present a synthetic method for the preparation of oxo-graphene nanoribbons (oxo-GNRs) by oxidative cleavage of C–C bonds of enriched (6,5)-single-walled carbon nanotubes (SWCNTs). We applied a mild oxidation protocol to oxidize SWCNTs involving sulfuric acid as dispersion medium and potassium permanganate as oxidant. The obtained oxo-GNRs exhibit stunning fluorescence properties with emission maxima of about 300 nm and 400 nm, respectively, depending on oxidation time. The analyses reveal that functional oxo-groups are predominantly located at the rims of oxo-GNRs. Next to lactones, 1,3-ketones are identified, which can be further reacted with hydrazine, most likely forming pyrazoline groups. Based on our data, we propose a chemical structure model for the oxo-GNRs. The model is based on an intact inner π-system, responsible for photoluminescence properties and oxo-functionalized rims of GNRs.

PtPd Atomic Layer Shelled PdCu Hollow Nanoparticles on Partially Unzipped Carbon Nanotubes for Breaking the Activity-Stability Trade-Off toward the Hydrogen Oxidation Reaction in Alkaline Media.

Developing highly active yet stable catalysts for the hydrogen oxidation reaction (HOR) in alkaline media remains a significant challenge. Herein, we designed a novel catalyst of atomic PtPd-layer shelled ultrasmall PdCu hollow nanoparticles (HPdCu NPs) on partially unzipped carbon nanotubes (PtPd@HPdCu/W-CNTs), which can achieve a high mass activity, 5 times that of the benchmark Pt/C, and show exceptional stability with negligible decay after 20,000 cycles of accelerated degradation test. The atomically thin PtPd shell serves as the primary active site for the HOR and a protective layer that prevents Cu leaching. Additionally, the HPdCu substrate not only tunes the adsorption properties of the PtPd layer but also prevents corrosive Pt from reaching the interface between NPs and the carbon support, thereby mitigating carbon corrosion. This work introduces a new strategy that leverages the distinct advantages of multiple components to address the challenges associated with slow kinetics and poor durability toward the HOR.

Effect of reaction temperature and concentration of H2SO4 acid in the unzipping process of carbon nanotubes to form graphene nanoribbons

Unzipping carbon nanotubes (CNTs) is one of the methods to produce graphene nanoribbons. In this research, we investigated the effect of reaction temperature and concentration of H2SO4 acid on graphene nanoribbons (GNRs) formation. By increasing the reaction temperature, the transformation of CNTs to form GNRs is getting better. The results showed that the unzipping process was strongly affected by temperature. At 100 °C temperature, GNRs obtained 100% yield with a purity of +99%C and surface area of 250 m2/g. Furthermore, H2SO4 acid is the only environment for the wet chemical reaction, it doesn’t affect GNRs quality so the low concentration of acid will be utilized and contribute to reducing the environmental impact in the world. The GNRs will be a potential material for both anode and cathode in batteries and supercapacitors to get higher energy density and fast charging properties.

Unzipped carbon nanotubes assisted 3D printable functionalized chitosan hydrogels for strain sensing applications

Developing multifunctional hydrogels for wearable strain sensors has received significant attention due to their diverse applications, including human motion detection, personalized healthcare, soft robotics, and human-machine interfaces. However, integrating the required characteristics into one component remains challenging. To overcome these limitations, we synthesized multifunctional hydrogels using carboxymethyl chitosan (CMCS) and unzipped carbon nanotubes (f-CNTs) as strain sensor via a one-pot strategy. The polar groups in CMCS and f-CNTs enhance the properties of the hydrogels through different interactions. The hydrogels show superior printability with a uniformity factor (U) of 0.996 ± 0.049, close to 1. The f-CNTs-assisted hydrogels showed improved storage modulus (8.8 × 105 Pa) than the pure polymer hydrogel. The hydrogels adequately adhered to different surfaces, including human skin, plastic, plastic/glass interfaces, and printed polymers.The hydrogels demonstrated rapid self-healing and good conductivity. The biocompatibility of the hydrogels was assessed using human fibroblast cells. No adverse effects were observed with hydrogels, showing their biocompatibility. Furthermore, hydrogels exhibited antibacterial potential against Escherichia coli. The developed hydrogel exhibited unidirectional motion and complex letter recognition potential with a strain sensitivity of 2.4 at 210 % strain. The developed hydrogels could explore developing wearable electronic devices for detecting human motion.

Ultrathin Two-dimensional Layered Composite Carbosilicates from in situ Unzipped Carbon Nanotubes and Exfoliated Bulk Silica.

A key task in today's inorganic synthetic chemistry is to develop effective reactions, routes, and associated techniques aiming to create new functional materials with specifically desired multilevel structures and properties. Herein, we report an ultrathin two-dimensional layered composite of graphene ribbon and silicate via a simple and scalable one-pot reaction, which leads to the creation of a novel carbon-metal-silicate hybrid family: carbosilicate. The graphene ribbon is in situ formed by unzipping carbon nanotubes, while the ultrathin silicate is in situ obtained from bulk silica or commercial glass; transition metals (Fe or Ni) oxidized by water act as bridging agent, covalently bonding the two structures. The unprecedented structure combines the superior properties of the silicate and the nanocarbon, which triggers some specific novel properties. All processes during synthesis are complementary to each other. The associated synergistic chemistry could stimulate the discovery of a large class of more interesting, functionalized structures and materials.

Ultrathin Two‐dimensional Layered Composite Carbosilicates from in situ Unzipped Carbon Nanotubes and Exfoliated Bulk Silica

AbstractA key task in today's inorganic synthetic chemistry is to develop effective reactions, routes, and associated techniques aiming to create new functional materials with specifically desired multilevel structures and properties. Herein, we report an ultrathin two‐dimensional layered composite of graphene ribbon and silicate via a simple and scalable one‐pot reaction, which leads to the creation of a novel carbon‐metal‐silicate hybrid family: carbosilicate. The graphene ribbon is in situ formed by unzipping carbon nanotubes, while the ultrathin silicate is in situ obtained from bulk silica or commercial glass; transition metals (Fe or Ni) oxidized by water act as bridging agent, covalently bonding the two structures. The unprecedented structure combines the superior properties of the silicate and the nanocarbon, which triggers some specific novel properties. All processes during synthesis are complementary to each other. The associated synergistic chemistry could stimulate the discovery of a large class of more interesting, functionalized structures and materials.

Unzipping Carbon Nanotubes to Sub-5-nm Graphene Nanoribbons on Cu(111) by Surface Catalysis.

Graphene nanoribbons (GNRs) are promising in nanoelectronics for their quasi-1D structures with tunable bandgaps. The methods for controllable fabrication of high-quality GNRs are still limited. Here a way to generate sub-5-nm GNRs by annealing single-walled carbon nanotubes (SWCNTs) on Cu(111) is demonstrated. The structural evolution process is characterized by low-temperature scanning tunneling microscopy. Substrate-dependent measurements on Au(111) and Ru(0001) reveal that the intermediate strong SWCNT-surface interaction plays a pivotal role in the formation of GNRs.

Unzipped multiwalled carbon nanotube oxide / PEG based phase change composite for latent heat energy storage

Polyethylene glycol (PEG) as a phase change material (PCM) is being explored for latent heat energy storage systems due to its high thermal storage capacity. In the current study, PCM composites were synthesized with different mass fractions of unzipped multiwalled carbon nanotube oxides (UMCNOs) in PEG by melt mixing method. The influence of UMCNOs loading on the thermal conductivity (TC), phase change properties such as temperatures and latent heats of melting and solidifying, thermal energy storage and release rates were investigated. At a loading of 6 mass% of UMCNOs, the TC of the prepared PCM composite increased by 2.1 times as compared to that of pure PEG (0.21 W/m-K). Differential scanning calorimetry analysis showed that as the concentration of UMCNOs increased, there was a slight decrease in the melting temperature. Additionally, the latent heats of melting were found to be reduced by 1.11–9.46 % with the addition of 0.5–6 mass% UMCNOs. Further, the thermal energy storage and release rates were improved with the addition of UMCNOs in PCM composites. In addition, there was negligible change in phase change properties after 100 melting and solidifying cycles of PCM composite, indicating the great prospects for the latent heat energy storage application.

Synergistic effect of Mn2+ with unzipped carbon nanotubes on enhancement of mechanical properties of polyamide 66

Multi-walled carbon nanotubes (MWCNTs) are widely recognized for their exceptional mechanical properties and potential to reinforce composite materials. However, the requirement for high MWCNT concentration remains a challenge in achieving effective reinforcement. In this study, using unzipped multi-walled carbon nanotubes (uMWCNTs) and transition metal filler as a means to significantly enhance the mechanical properties of polyamide 66 (PA66) and incorporating 0.2% w/w of uMWCNTs-Mn as filler allowed us to increase PA66's tensile strength by over 74% and its Young's modulus by over 100%. The structural and functional integrity of uMWCNTs-Mn and PA66 matrix were investigated in detail. This work reveals that the enhancement of mechanical properties is mainly due to the interfacial interaction between uMWCNTs-Mn sheets and the PA66 matrix, the coupling effect of manganese ions, and increases the crystallinity and reduces the size of microcrystals. This work's findings provide a novel approach to the preparation of high-performance composites with low concentrations of carbon nanostructures, which holds significant implications for the development of advanced materials.

Computation-aided design of oxygen-ligand-steered single-atom catalysts: Sewing unzipped carbon nanotubes

Computation-aided design of oxygen-ligand-steered single-atom catalysts: Sewing unzipped carbon nanotubes

Ni Single Atoms Embedded in Graphene Nanoribbon Sieves for High-Performance CO2 Reduction to CO.

Ni single-atom catalysts (SACs) are appealing for electrochemical reduction CO2 reduction (CO2 RR). However, regulating the balance between the activity and conductivity remains a challenge to Ni SACs due to the limitation of substrates structure. Herein, the intrinsic performance enhancement of Ni SACs anchored on quasi-one-dimensional graphene nanoribbons (GNRs) synthesized is demonstrated by longitudinal unzipping carbon nanotubes (CNTs). The abundant functional groups on GNRs can absorb Ni atoms to form rich Ni-N4 -C sites during the anchoring process, providing a high intrinsic activity. In addition, the GNRs, which maintain a quasi-one-dimensional structure and possess a high conductivity, interconnect with each other and form a conductive porous framework. The catalyst yields a 44 mA cm-2 CO partial current density and 96% faradaic efficiency of CO (FECO ) at -1.1V vs RHE in an H-cell. By adopting a membrane electrode assembly (MEA) flow cell, a 95% FECO and 2.4V cell voltage are achieved at 200 mAcm-2 current density. This work provides a rational way to synthesize Ni SACs with a high Ni atom loading, porous morphology, and high conductivity with potential industrial applications.

Assembly of partially unzipped multiwalled carbon nanotubes into ultralight, highly efficient and multifunctional electromagnetic wave absorbing aerogel

Efficient electromagnetic wave absorbing materials with lightweight and multifunctional integrated applications have broad development application prospects. Carbonaceous materials are one of the promising candidates due to their low density, high conductivity, diverse structure and tunable composition. Here, we prepared nitrogen-doped graphene nanoribbon/carbon nanotube (N-GNR/CNT) hybrid aerogel by assembling and annealing partially unzipped carbon nanotubes. The remaining CNTs serve as skeletons to maintain GNR unfolding, while the unfolded GNRs serve as “wings” to interconnect and form a 3D network. The 3D network provides channels for fast electron transmission, and meanwhile GNRs offer rich edges for N doping. Benefitting from the synergistic effect of CNTs and GNRs, this aerogel shows the characteristics of ultralight, ultrathin, strong electromagnetic wave absorption and efficient joule heating. This study presents a new strategy for preparing multifunctional electromagnetic wave absorbing materials, and broadens the application of graphene nanoribbons.

Chemically engineered unzipped multiwalled carbon nanotube and rGO nanohybrid for ultrasensitive picloram detection in rice water and soil samples

Picloram (4-Amino-3,5,6-trichloro pyridine-2-carboxylic acid) is a chlorinated herbicide that has been discovered to be tenacious and relatively durable in both soil and water. It is known to have adverse and unpleasant effects on humans causing several health complications. Therefore, the determination of picloram is profoundly effective because of its bio-accumulative and persistent nature. Because of this, a sensitive, rapid, and robust detection system is essential to detect traces of this molecule. In this study, we have constructed a novel nanohybrid system comprising of an UZMWCNT and rGO decorated on AuNPs modified glassy carbon electrode (UZMWCNT + rGO/AuNPs/GCE). The synthesized nanomaterials and the developed system were characterized using techniques such as SEM, XRD, SWV, LSV, EIS, and chronoamperometry. The engineered sensor surface showed a broad linear range of 5 × 10–2 nM to 6 × 105 nM , a low limit of detection (LOD) of 2.31 ± 0.02 (RSD < 4.1%) pM and a limit of quantification (LOQ) of 7.63 ± 0.03 pM. The response time was recorded to be 0.2 s, and the efficacy of the proposed sensor system was studied using rice water and soil samples collected from the agricultural field post filtration. The calculated recovery % for picloram in rice water was found to be 88.58%—96.70% (RSD < 3.5%, n = 3) and for soil it was found to be 89.57%—93.24% (RSD < 3.5%, n = 3). In addition, the SWV responses of both the real samples have been performed and a linear plot have been obtained with a correlation coefficient of 0.97 and 0.96 for rice and soil samples, respectively. The interference studies due to the coexisting molecules that may be present in the samples have been found to be negligible. Also, the designed sensor has been evaluated for stability and found to be highly reproducible and stable towards picloram detection.

Synthesized partially unzipped carbon nanotubes and potential DNA/CNTs interactions

Carbon nanotubes (CNTs) are structurally considered to be graphene nano-ribbons (GNRs) that rolled up into seamless tubes. While CNTs nanotechnology is advancing, synthesis of GNRs from CNTs is sought after for precise and integrative graphene applications. Acid treatment of CNTs can generate longitudinal unzipping in an effective, large scale and economic approach. However, further understanding of CNTs-to-GNRs degradation, which mimics biodegradation molecular processes by oxidants, can also aid to assess toxicological impact of biodegraded CNTs. In this study, unzipping of multi-wall carbon nanotubes (MWCNTs) was established using a strong oxidizing agent. The influence of oxidation on the morphological, crystalline quality and dielectric properties was investigated. In particular, partial unzipping of CNTs was confirmed by transmission electron microscopy (TEM), and scanning electron microscopy (SEM) images. Broad band dielectric spectroscopy (BDS) was utilized to depict the influence of the applied frequency on the dielectric properties. GNRs exhibited a lag in the drop of capacitance and impedance to higher values of frequency with respect to the starting MWCNTs. Furthermore, DNA interactions with partially unzipped carbon nanotubes, were computationally assessed by employing molecular docking. The obtained potential DNA-CNT molecular conformations were illustrated and their biomolecular implications were discussed.

Degradation behavior, cytotoxicity, hemolysis of partially unzipped carbon nanotubes/zinc composites as potential biodegradable bone implants

Zn with a suitable degradation rate is considered to be a promising candidate biodegradable implant materials. To enhance the mechanical properties of pure Zn and broaden its application in the field of short-term orthopedic surgery, a series of new Zn matrix composites with a high strength are developed by the addition of partially unzipped carbon nanotubes (PUCNTs), and the degradation behavior, cytotoxicity and hemolysis of new PUCNTs/Zn composites are investigated in this paper. The results show that the degradation rate of the PUCNTs/Zn composites with 0, 0.1, 0.2, 0.3 and 0.5 wt.% PUCNTs can meet the standard of clinical biomedical orthopedic implant materials. During cytotoxicity test, the density of living cells rapidly increases with increasing PUCNTs content, and the cell viability of MG-63 cells in the extract with different concentrations is higher than 90%, illustrating an excellent cytocompatibility. For the hematotoxicity assay, the hemolysis percentage of all PUCNTs/Zn composites samples is below the safety threshold of 5.0% for clinical application, exhibiting a good blood compatibility.

Acetylation Strategy for Unzipping Carbon Nanotubes in High-Performance Lithium-Ion Batteries

Acetylation Strategy for Unzipping Carbon Nanotubes in High-Performance Lithium-Ion Batteries

Graphene Properties, Synthesis and Applications: A Review.

We have evaluated some of the most recent breakthroughs in the synthesis and applications of graphene and graphene-based nanomaterials. This review includes three major categories. The first section consists of an overview of the structure and properties, including thermal, optical, and electrical transport. Recent developments in the synthesis techniques are elaborated in the second section. A number of top–down strategies for the synthesis of graphene, including exfoliation and chemical reduction of graphene oxide, are discussed. A few bottom–up synthesis methods for graphene are also covered, including thermal chemical vapor deposition, plasma-enhanced chemical vapor deposition, thermal decomposition of silicon, unzipping of carbon nanotubes, and others. The final section provides the recent innovations in graphene applications and the commercial availability of graphene-based devices.