vdW Interactions Research Articles

A Density Functional Benchmark for Dehydrogenation and Dehalogenation Reactions on Coinage Metal Surfaces.

The on-surface synthesis of low-dimensional organic nanostructures has been extensively investigated through both experimental and theoretical methods, particularly by density functional theory (DFT). However, the complex mixture of interactions often poses challenges within the DFT framework, and there is a knowledge-gap regarding how the choice of DFT approach affects the computed results. Here, five different approaches including vdW interactions, i. e., PBE+D3, PBE+vdWsurf, rev-vdWDF2, r2SCAN+rVV10 and BEEF-vdW, are employed to describe three prototypical on-surface reactions; dehydrogenation of benzene, debromination of bromobenzene, and deiodination of iodobenzene on the (111) facets of the coinage metals. Overall, rev-vdW-DF2 outperforms the other methods in describing benzene adsorption, whereas BEEF-vdW falls short. For dehydrogenation and debromination on Cu(111), all functionals except BEEF-vdW give reasonable activation energies compared to experiments. A similar trend is observed for Ag(111) and Au(111), with BEEF-vdW yielding significantly higher activation and reaction energies. For dehalogenation, all the five vdW approaches correctly capture the reactivity trend - Cu(111)>Ag(111)>Au(111) - and the expected hierarchy between bromobenzene desorption and carbon-bromine activation. Only BEEF-vdW fails to predict the faster kinetics of deiodination than the iodobenzene desorption. Our work forms a basis for evaluating density functionals in describing chemical reactions on surfaces.

Dimerization of the Aβ42 under the Influence of the Gold Nanoparticle: A REMD Study.

Advances in Alzheimer's disease (AD) are related to the oligomerization of Amyloid β (Aβ) peptides. Therefore, alteration of the process can prevent AD. We investigated the Aβ42 dimerization under the effects of gold nanoparticles using temperature replica-exchange molecular dynamics (REMD) simulations. The structural change of dimers in the presence and absence of the gold nanoparticle, Au55, was monitored over stable intervals. Physical insights into the oligomerization of Aβ were thus clarified. The computed metrics indicate that Au55 affects the progress of oligomerization. Specifically, the presence of the gold nanoparticle significantly modifies the structure of dimeric Aβ42. The β-content experienced a substantial decrease with the induction of Au55. The turn and coil-contents are also decreased under the effects of the gold nanoparticle. However, the α-content of the dimer exhibited a rigid increase. The influence of gold nanoparticles on the dimeric Aβ42 differs significantly from that of silver nanoparticles, which reduce β-content but increase coil-, turn-, and α-contents. The nature of inhibition will be discussed, in which the vdW interaction plays a driving force for the interaction between the Aβ42 dimer and the gold nanoparticle.

Molecular Dynamics of Catalyst-Free Edge Elongation of Boron Nitride Nanotubes Coaxially Grown on Single-Walled Carbon Nanotubes.

Recent advances in low-dimensional materials have enabled the synthesis of single-walled carbon nanotubes encapsulated in hexagonal boron nitride (BN) nanotubes (SWCNT@BNNT), creating one-dimensional van der Waals (vdW) heterostructures. However, controlling the quality and crystallinity of BNNT on the surface of SWCNTs using chemical vapor deposition (CVD) remains a challenge. To better understand the growth mechanism of the BNNT in SWCNT@BNNT, we conducted molecular dynamics (MD) simulations using empirical potentials. The simulation results suggest that spontaneous BN nucleation is unlikely to occur on the outer surface of the SWCNT when we assume only vdW interaction between the BN and SWCNT layers. However, we observe the elongation of the BNNT when a short BNNT is provided as a seed nucleus on the SWCNT. This grown BNNT structure, with its sharply cut edges, aligns with experimental observations made using transmission electron microscopy (TEM). Moreover, the edge-reconstruction process favors zigzag B edges, which exhibit low edge energy according to the ReaxFF potential. Our simulation successfully provides insights into the catalyst-free growth process of this one-dimensional vdW heterostructure.

Evaluation of β‐ and γ‐Cyclodextrins as Promising Bisoprolol Drug Carriers: Docking, Molecular Dynamics and MM‐PBSA1 Free‐Energy Calculations*

AbstractIn this research work, the binding mechanism of Bisoprolol (BIS) drug into the beta‐cyclodextrin (β‐CD) and gamma‐cyclodextrin (γ‐CD) nanopores were investigated using docking, molecular dynamics (MD) simulations, and MM‐PBSA free energy calculations. Also, we assessed the energetic aspects within the BIS‐CDs complex under different thermal conditions in four stages from 298 to 334 K, which includes mammalian body temperature in order to approximate physiological conditions. The computational results reveal that the encapsulation of the BIS into the cavities of CDs is reinforced by hydrogen bonds (HBs) and van der Waals (vdW) interactions in the aqueous phase. The stability of the inclusion complexes of β and γ‐CD with BIS was confirmed by evaluating system stability, flexibility, dynamic and thermodynamic properties at all temperature steps. Next, we analyzed the degree of complexation between BIS and CDs at four different temperatures. The findings revealed that the degree of complexation is decreased as the temperature is increased. The translational movement of the drug to the outside of the CDs cavity increased in the temperature range of 310 to 334 K in γ‐CD more than β‐CD. The β‐CD complex exhibits greater stability compared to the γ‐CD complex in the aqueous medium. The MM‐PBSA free energy approach also confirms more binding affinity of BIS drug into the β‐CD cavity. keywords: Bisoprolol, β‐cyclodextrin, γ‐cyclodextrin, Molecular dynamics, MM‐PBSA free energy.

Potential toxicity of Graphene (Oxide) quantum dots to human intestinal fatty acid binding protein (HIFABP) via obstructing the protein’s openings

Graphene quantum dots (GQDs) have garnered significant attention across numerous fields due to their ultrasmall size and exceptional properties. However, their extensive applications may lead to environmental exposure and subsequent uptake by humans. Yet, conflicting reports exist regarding the potential toxicity of GQDs based on experimental investigations. Therefore, a comprehensive understanding of GQD biosafety requires further microscopic and molecular-level investigations. In this study, we employed molecular dynamics (MD) simulations to explore the interactions between GQDs and graphene oxide quantum dots (GOQDs) with a protein model, the human intestinal fatty acid binding protein (HIFABP), that plays a crucial role in mediating the carrier of fatty acids in the intestine. Our MD simulation results reveal that GQDs can be adsorbed on the opening of HIFABP, which serves as an entrance for the fatty acid molecules into the protein’s interior cavity. This adsorption has the potential to obstruct the opening of HIFABP, leading to the loss of its normal biological function and ultimately resulting in toxicity. The adsorption of GQDs is driven by a combination of van der Waals (vdW), π-π stacking, cation-π, and hydrophobic interactions. Similarly, GOQDs also exhibit the ability to block the opening of HIFABP, thereby potentially causing toxicity. The blockage of GOQDs to HIFABP is guided by a combination of vdW, Coulomb, π-π stacking, and hydrophobic interactions. These findings not only highlight the potential harmful effects of GQDs on HIFABP but also elucidate the underlying molecular mechanism, which provides crucial insights into GQD toxicology.

Van der Waals epitaxial growth of single-crystal molecular film.

Epitaxy is the cornerstone of semiconductor technology, enabling the fabrication of single-crystal film. Recent advancements in van der Waals (vdW) epitaxy have opened new avenues for producing wafer-scale single-crystal 2D atomic crystals. However, when it comes to molecular crystals, the overall weak vdW force means that it is a significant challenge for small molecules to form a well-ordered structure during epitaxy. Here we demonstrate that the vdW epitaxy of Sb2O3 molecular crystal, where the whole growth process is governed by vdW interactions, can be precisely controlled. The nucleation is deterministically modulated by epilayer-substrate interactions and unidirectional nuclei are realized through designing the lattice and symmetry matching between epilayer and substrate. Moreover, the growth and coalescence of nuclei as well as the layer-by-layer growth mode are kinetically realized via tackling the Schwoebel-Ehrlich barrier. Such precise control of vdW epitaxy enables the growth of single-crystal Sb2O3 molecular film with desirable thickness. Using the ultrathin highly oriented Sb2O3 film as a gate dielectric, we fabricated MoS2-based field-effect transistors that exhibit superior device performance. The results substantiate the viability of precisely managing molecule alignment in vdW epitaxy, paving the way for large-scale synthesis of single-crystal 2D molecular crystals.

Strong Dependence of Point Defect Properties in Metal Halide Perovskites on Description of van der Waals Interaction.

Weaker than ionic and covalent bonding, van der Waals (vdW) interactions can have a significant impact on structure and function of molecules and materials, including stabilities of conformers and phases, chemical reaction pathways, electro-optical response, electron-vibrational dynamics, etc. Metal halide perovskites (MHPs) are widely investigated for their excellent optoelectronic properties, stemming largely from high defect tolerance. Although MHPs are primarily ionic compounds, we demonstrate that vdW interactions contribute ∼5% to the total energy, and that static, dynamics, electronic and optical properties of point defects in MHPs depend significantly on the vdW interaction model used. Focusing on widely studied CsPbBr3 with the common Br vacancy and interstitial defects, we compare the PBE, PBE+D3, PBE+TS, PBE+TS/HI and PBE+MBD-NL models and show that vdW interactions strongly alter the global and local geometric structure, and change the fundamental bandgap, midgap state energies and electron-vibrational coupling. The vdW interaction sensitivity stems from involvement of heavy and highly polarizable chemical elements and the soft MHP structure.

The adsorption of p-hydroxybenzoic acid on graphene oxide under different pH and in-situ desorption in direct current electric field

The development and ongoing optimization of measures to reduce and eliminate p-hydroxybenzoic acid (p-HBA) in industrial wastewater are significant due to its potential carcinogenic effect and bio-recalcitrant. Graphene oxide (GO) is an ideal adsorbent for removing aromatic acids and achieving adsorbent recovery and resource conservation. In this study, the adsorption properties of p-HBA onto GO at different pH values and the regeneration mechanism of adsorbent under varying electric field intensities were analyzed using molecular dynamics (MD) simulation. The simulation results demonstrate that GO exhibits preferable adsorption capabilities for p-HBA at low pH, and van der Waals (vdW) interaction plays a leading role. However, the adsorption stability decreases at high pH (particularly pH > 9.3) with most p-HBA desorption from the GO surface. When an electric field of 1.0 V/nm is applied to the acidic system (HGO_HBA_HBA−), the total adsorption interaction energy between GO and p-HBA decreases but remains high (−1836.93 kJ/mol). When a 0.6 V/nm electric field is added to the alkaline system (GO2−_HBA2−), the vdW and electrostatic interaction energies are recorded as −35.34 kJ/mol and 3546.97 kJ/mol. The vdW interaction is weak, and electrostatic repulsion increases, facilitating the desorption of p-HBA from the GO surface. This work aims to share insights into the microscopic removal mechanism of p-HBA on the GO surface under different pH values and provide a theoretical perspective on the regeneration mechanism of GO.

Encapsulation of linear carbon chains in single-walled carbon nanotubes: Towards 1D van der Waals heterostructures for high-efficiency excitonic solar cells

One-dimensional van der Waals heterostructures (1D vdW HTs) based on single-walled carbon nanotubes (SWCNTs) encapsulating linear carbon chains (LCCs) with tunable optoelectronic properties provide a fresh ground for efficient excitonic solar cells (XSCs) alternative to those based on 2D monolayer materials. As an effort to identify for the first time 1D vdW HTs for efficient XSCs application, we perform here a systematic theoretical investigation on the energetic and structural stability, optoelectronic and photovoltaic properties of 1D vdW HTs based on SWCNTs encapsulating 50 symmetrical LCCs of different lengths, and capped with different conjugated endgroups through comprehensive first-principles calculations. We showed the fundamental role of the length and the endgroups effects in modulating the optoelectronic properties of LCCs. Through exploration of the energetic stability of the 1D vdW HTs of LCCs@SWCNTs from the universal force field (UFF) including vdW interactions, we determined the optimal SWCNTs diameters for which the resulting 1D vdW HTs are stable. Then, the band alignment in the 50 stable 1D vdW HTs of LCCs@SWCNTs is examined. Intriguingly, stable LCCs@SWCNTs are identified as type-II 1D vdW HTs complying the prerequisite of XSCs with strong optical absorption in the UV–visible-NIR spectral regions, and power conversion efficiency (PCE) reaching well over 21 %. These findings unravel the enormous potential of the 1D vdW HTs in designing next-generation XSCs devices competitive with state-of-the-art solar cells.

Unveiling Versatile Electronic Properties and Contact Features of Metal-Semiconductor Graphene/γ-Ge2SSe van der Waals Heterostructures.

Recently, searching for a metal-semiconductor junction (MSJ) that exhibits low-contact resistance has received tremendous consideration, as they are essential components in next-generation field-effect transistors. In this work, we design a MSJ by integrating two-dimensional (2D) graphene as the metallic electrode and 2D Janus γ-Ge2SSe as the semiconducting channel using first-principles simulations. All the graphene/γ-Ge2SSe MSJs are predicted to be energetically, mechanically, and thermodynamically stable, characterized by the weak van der Waals (vdW) interactions. The graphene/γ-SGe2Se MSJ-vdWH form the n-type Schottky contact (SC), while the graphene/γ-SeGe2S MSJ-vdWH form the p-type one, suggesting that the switching between p-type and n-type SC in the graphene/γ-Ge2SSe MSJ-vdWHs can occur spontaneously by simply altering the stacking patterns, without requiring any external conditions. Notably, the contact features, including contact types and barriers of the graphene/γ-Ge2SSe MSJs are significant in versatility and can be altered by applying electric gating and adjusting interlayer spacing. Both the applied electric gating and strain engineering induce switchability between p- and n-type and SC to OC in the graphene/γ-Ge2SSE MSJs. This versatility underscores the potential of the graphene/γ-Ge2SSe MSJ for next-generation applications that require low-contact resistance and high performance.

Study of carbon monoxide adsorption on the α- and γ-graphyne nanosheets for the sensor applications

Recently, graphyne-based gas sensors have drawn a lot of interest. One kind of graphene with acetylene bonds connecting its hexagons is graphyne. In this study, the density functional theory (DFT) method was used to investigate the physical parameters of the surface adsorption of carbon monoxide on the [Formula: see text]- and [Formula: see text]-graphyne nanosheet, taking into account van der Waals (vdW) interactions through the use of the SIESTA computational code. CO molecule adsorbed and optimized in two vertical and horizontal states from the side of carbon and oxygen atoms, at different distances and sites relative to the graphyne sheet. After optimization and finding the adsorption energy, the best adsorption sites, equilibrium distance of the molecule from the surface, electronic structure, charge transfer rate, and bandgap changes were calculated. It was observed that the changes in the electronic structure after the adsorption of CO molecule are insignificant and the [Formula: see text]- and [Formula: see text]-graphyne nanosheets remained zero-gap and narrow-gap semiconductors, respectively. The adsorption of CO molecule on the [Formula: see text]- and [Formula: see text]-graphyne nanosheets is physisorption. The results show that the [Formula: see text]-graphyne nanosheet has a good potential for adsorbing and detecting CO molecules and sensor applications.

Effects of graphene reinforcement on morphology, thermophysical, and mechanical properties of polyvinyl alcohol and polyacrylamide in condensed phases

The subtle interplay of noncovalent interaction in enhancing the compatibility between the graphene-based material and the oligomers of polyvinyl alcohol (PVA) and polyacrylamide (PAM) in the solvent phase is unraveled within the framework of all-atom classical force field-based molecular dynamics (MD) simulations. The decomposition of binding free energy analysis demonstrates that the interaction between polymer segments and graphene (G)-surface crucially emanates from the van der Waals (vdW) interactions, while the adsorption of polymer chains on the graphene oxide (GO)-surface is influenced by vdW and electrostatic interactions. The influence of diverse factors including the strain rate, the size of the nanofiller, the number of oligomers, and the thermal quenching rate on controlling the morphology, mechanical, and thermophysical properties of the graphene-reinforced polymer nanocomposites are further explored. The uniaxial deformation simulations of the graphene-reinforced PVA and PAM matrices show that the interfacial mechanical strength is escalated for the G-PVA nanocomposite. The inclusion of graphene nanofiller reduces the polymer chain mobility and increases the intermolecular interaction, which in turn enhances the toughness of the graphene-polymer composites. Increasing the strain rate raises the yield strength and modulus, making the composites appear stronger and stiffer. As evidenced by the predicted glass transition temperature, the thermal stability of the PVA and PAM matrices is significantly improved by the graphene reinforcement.

Geometric optimisation and structural properties of organic−inorganic halide perovskites from van der Waals density functional theory calculations

Organic–inorganic hybrid perovskites have attracted extensive attention in the photovoltaic field due to their unique photoelectric properties and low production costs. Using the density functional theory-based first-principles calculations, we reported the geometric optimisation and structural properties of halide perovskites using van der Waals density functional theory calculations. The strongly constrained and appropriately normed (SCAN) meta-GGA with the revised Vydrov-van Voorhis no-local correlation functional (SCAN + rVV10) are promising van der Waals density functional for solving van der Waals (vdW) interaction problems that many non-empirical semilocal functionals fail to include. We found the optimised structure parameters of halide perovskites based on the SCAN + rVV10 functionals are much closer to the experimental results than other functional including PBE and PBE + vdW-TS functionals, which provides the fundamental aspect for the theoretical calculations of surfaces, interfaces, optical properties, and structure-properties relationship.

Microscopic mechanism investigation of extraction of lignin by benzyltriethylammonium chloride-based deep eutectic solvents

Benzyltriethylammonium chloride (BTEAC)-based deep eutectic solvent (DES) has a high delignification rate in the pretreatment of lignocellulose, and the lignin obtained from the removal has the advantages of high purity and low molecular weight. The interaction mechanism between BTEAC-based DES and lignin at molecular level was investigated by multiscale simulation analytical approach. By analyzing the types of weak interaction, charge distribution, number of hydrogen bonds, energy distribution and density distribution in different systems, the influence of six hydrogen bond donor (HBD) structures on the extraction process was clarified. The interaction between Cl- and lignin is mainly electrostatic interaction, and the interaction between BTEA+ and lignin is mainly van der Waals (vdW) interaction. The original π-π stacking of lignin is replaced by the new π-π stacking between BTEA+ and lignin. The effects of different functional groups and length of carbon chain on the interaction were researched. The acidic HBD with short carbon chain has a larger interaction and can affect the ether bond on the lignin. Among them, due to the smaller volume of formic acid (FA), it provides more space for BTEA+ to contact with lignin, resulting in stronger interaction. The molecular-level theoretical foundation underpinning the efficacy of BTEAC-FA in lignin removal during the pretreatment process is provided.

Nonlocal FG porous adsorber with 2D PSH network under magnetic intensity for large frequency range considering vdW interaction potentials

In this contribution, the nonlocal frequency shift is investigated and analyzed for an adatoms-microstructure system, considering the effects of nonlocal behavior, adatom distribution, and magnetic field. The microstructure is a sandwich microbeam including face sheets that are functionally graded porous (FGP) and a longitudinally perforated core with a uniform periodic square hole’s network (PSH) arranged parallel to the length of the sandwich microbeam. The material characteristics for three layers are assumed to change along the thickness correspondingly to a power law function, where Maxwell’s equations are exploited to express how the applied magnetic field has been affected. Eringen’s nonlocal elasticity is utilized to incorporate small-scale behavior. At the same time, van der Waals interactions between the adatom itself and the adatom microstructure substrate are established employing Lennard-Jones (6–12) and Morse potentials to account for the energy induced by adsorption. The dynamic equations of vibration are modified to develop the Euler–Bernoulli beam model (EBM) and Levinson beam model (LBM), which are then solved using Navier solution method (NSM) and differential quadrature method (DQM) to determine the resonance shift. Numerical results revealed that the calculated shift response was influenced by the perforation characteristics, adsorbed adatoms, magnetic field intensity, and small-scale behavior. Consequently, numerical results are discussed to investigate the nonlocal dynamic response of adatom-microstructure systems, which are relevant to developing mass sensing devices incorporated into micro/nanoelectromechanical systems (M/NEMS).

Optical quantification of the weak van der Waals coupling between multilayer antimonene and bilayer MoS2 using ultrafast coherent vibration spectroscopy.

Antimonene, a promising conductor for next-generation 2D-based devices, has its contact resistance significantly influenced by the van der Waals (vdW) interaction within its heterostructure. In this study, we report the quantification of the vdW coupling between multilayer antimonene and bilayer MoS2 by ultrafast coherent vibration spectroscopy. By utilizing a femtosecond laser, we excited coherent acoustic vibrations in the multilayer-antimonene on substrate-supported bilayer MoS2, and the relative displacement at the vdW heterojunction was detected with the aid of bilayer MoS2. The photoexcited strain pulse generated in the multilayer-antimonene was observed as it transported to the bilayer MoS2, explaining the distortion at the beginning of the oscillation. By analyzing the thickness-dependent oscillation frequencies, we determine the effective vdW elastic constant between multilayer-antimonene and MoS2 to be (1.9 ± 0.2) × 1018N/m3. This non-destructive optical technique offers a significant advance in the evaluation of vdW interactions at 2D metal-semiconductor interfaces.

Direct Growth of Wafer-Scale Self-Separated GaN on Reusable 2D Material Substrates.

Free-standing gallium nitride has been prepared using various methods; however, the removal of the original substrate is still challenging with low success rates. In this work, 2-inch free-standing GaN films are obtained by direct growth on a fluoro phlogopite mica by hydride vapor-phase epitaxy. Depending on the van der Waals (vdW) interaction between GaN and mica, the effect of the significant lattice mismatch is effectively reduced; thus, enabling the production of a high-quality wafer-scale GaN film on mica. The vdW-induced cracks at GaN-mica interface are found to be initiated near the interface so that GaN can easily separate from mica during rapid cooling. Owing to the hydrophilic nature of mica, the residual GaN on the mica can be lifted off by following deionized water treatment, and the mica substrate can be repeatedly used to grow free-standing GaN films. The self-separated GaN films grown on both pristine and used mica substrates are single crystallinity and strain-free. Additionally, a fully functional ultraviolet light-emitting diode is demonstrated to show that the self-separated GaN films are of device quality. The proposed approach achieves epitaxial growth of wafer-scale single-crystalline GaN on 2D materials and provides a new substrate option in the technology of III-V materials.

Molecular modeling to elucidate the dynamic interaction process and aggregation mechanism between natural organic matters and nanoplastics

The interactions of nanoplastics (NPs) with natural organic materials (NOMs) dominate the environmental fate of both substances and the organic carbon cycle. Their binding and aggregation mechanisms at the molecular level remain elusive due to the high structural complexity of NOMs and aged NPs. Molecular modeling was used to understand the detailed dynamic interaction mechanism between NOMs and NPs. Advanced humic acid models were used, and three types of NPs, i.e., polyethylene (PE), polyvinyl chloride (PVC), and polystyrene (PS), were investigated. Molecular dynamics (MD) simulations revealed the geometrical change of the spontaneous formation of NOMs-NPs supramolecular assemblies. The results showed that pristine NPs initially tend to aggregate homogeneously due to their hydrophobic nature, and then NOM fragments are bound to the formed NP aggregates mainly by vdW interaction. Homo- and hetero-aggregation between NOMs and aged NPs occur simultaneously through various mechanisms, including intermolecular forces and Ca2+ bridging effect, eventually resulting in a mixture of supramolecular structures. Density functional theory calculations were employed to characterize the surface properties and reactivity of the NP monomers. The molecular polarity indices for unaged PE, PS, and PVC were 3.1, 8.5, and 22.2 ​kcal/mol, respectively, which increased to 43.2, 51.6, and 42.2 ​kcal/mol for aged NPs, respectively, indicating the increase in polarity after aging. The vdW and electrostatic potentials of NP monomers were visualized. These results clarified the fundamental aggregation processes, and mechanisms between NPs and NOMs, providing a complete molecular picture of the interactions of nanoparticles in the natural aquatic environment.

Van der Waals phase transition investigation toward high-voltage layered cathodes.

High-voltage phase transition constitutes the major barrier to accessing high energy density in layered cathodes. However, questions remain regarding the origin of phase transition, because the interlayer weak bonding features cannot get an accurate description by experiments. Here, we determined van der Waals (vdW) interaction (vdWi) in LixCoO2 via visualizing its electron density, elucidating the origin of O3─O1 phase transition. The charge around oxygen is distorted by the increasing Co─O covalency. The charge distortion causes the difference of vdW gap between O3 and O1 phases, verified by a gap corrected vdW equation. In a high charging state, excessive covalency breaks the vdW gap balance, driving the O3 phase toward a stable O1 one. This interpretation of vdWi-dominated phase transition can be applied to other layered materials, as shown by a map regarding degree of covalence. Last, we introduce the cationic potential to provide a solution for designing high-voltage layered cathodes.

Self-Scrolling of a Graphyne Ribbon Near a CNT in Multiphysical Environments.

Graphyne nanoscrolls (GNSs) have attracted significant research interest because of their wide-ranging applications. However, the production of GNSs via a self-scrolling approach is environment dependent. Here, molecular dynamics simulations are conducted to evaluate the self-scrolling behavior of an α-graphyne (α-GY) ribbon on a carbon nanotube (CNT) within various multiphysical environments, accounting for the interactions among temperature, electric field, and argon gas. The results demonstrate that the fabrication of an α-GNS lies in the interplay of van der Waals (vdW) forces among the components in a vacuum. Notably, the α-GY ribbon is easier to scroll onto a thicker CNT. The electric field attenuates the vdWinteraction, necessitating thicker CNTs for successful self-scrolling under a stronger electric field. In argon, both the vdW interaction and nanoscale pore contribute to the overlap formation. At 300 K, increasing argon density prolongs the time required for α-GNS formation, with self-scrolling failing beyond a critical gas density threshold. Moreover, the self-scrolling becomes easier at higher temperatures. In multiphysical environments, the interplay between the electric field and the gas density dictates the self-scrolling at low temperatures. Finally, reasonable suggestions are given for successful self-scrolling. The conclusions offer valuable insights for the practical fabrication of α-GNS.