Predicting the strain-mediated topological phase transition in 3D cubic ThTaN₃

• Chunmei Zhang and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1399–1404, doi:10.3762/bjnano.9.132

• –correlation functional was used. The hybrid Heyd–Scuseria–Ernzerhof (HSE06) functional [34][35] was adopted for the accurate calculation of band structures of 3D ThTaN3. A plane-wave basis set with an energy cut-off of 500 eV was employed and long range van der Waals dispersion [36] was incorporated to

• ) [1]. The band gap should exhibit substantial differences depending on the relative weights of the Hartree–Fock and traditional LDA or GGA exchange energies in the hybrid functional as well as those of the long range van der Waals interactions. However, we found that the impact of van der Waals

Atomic-level characterization and cilostazol affinity of poly(lactic acid) nanoparticles conjugated with differentially charged hydrophilic molecules

• María Francisca Matus,
• Martín Ludueña,
• Cristian Vilos,
• Iván Palomo and
• Marcelo M. Mariscal

Beilstein J. Nanotechnol. 2018, 9, 1328–1338, doi:10.3762/bjnano.9.126

• different biological molecules inside the organism [52]. The interaction energies between the polymeric phase (PLA) and the lipid portion (DSPE–PEG) (Table 1) were similar in all cases and it is governed by hydrophobic interactions. Despite that van der Waals energy was similar in all formulations

• (−664,536.34, −661,500.71 and −659,315.18 kcal/mol for carboxy-, methoxy- and amino-terminated NPs, respectively), the slightly lower energetic contribution (total energy (Etotal), potential energy (PE) and kinetic energy (KD), and van der Waals (vdW) energy (EvdW)) obtained in the amino-terminated NPs could

• process will be studied. Schematic representation of PLA core formation process. Ball and stick representation of A) lactic acid monomer unit and atom definition for polymeric chain formation, B) poly(D,L-lactic acid) 20 monomer structure and C) van der Waals representation of 10 PLA chains with 20

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• calculations. It was subsequently used as a generic reference for aligning the band positions that were obtained from HSE06-Wannier calculations. A zero-damped van der Waals correction was incorporated using the DFT-D3 method of Grimme’s scheme [24][25] to better describe non-covalent bonding interactions. The

• atomic layers interacting with neighboring layers through weak van der Waals forces. Detailed structural parameters for bulk and monolayers of SiAs2 and GeAs2 are listed in Table 1. The calculated lattice constants for the bulk materials are in good agreement with previous experimental values [4]. The

• strength of van der Waals interactions in the bulk materials of SiAs2 and GeAs2. Thus, the lower the formation energy the easier it can be extracted from the bulk material. It has been reported that less than 200 meV/atom is considered to be a sufficiently low formation energy that the free-standing 2D

Electrostatic force spectroscopy revealing the degree of reduction of individual graphene oxide sheets

• Yue Shen,
• Ying Wang,
• Yuan Zhou,
• Chunxi Hai,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 1146–1155, doi:10.3762/bjnano.9.106

• superposes on the van der Waals force between the tip and sample so that both forces contribute to the imaging. In recent years, its applications have been extended to study the local dielectric properties of semiconductor nanomaterials such as GO sheets or partially reduced rGO sheets [20][21][22], graphene

• information (blue arrows marked in Figure 1i,k), indicating the contributions from the polarization force (dielectric properties) and the van der Waals force (topography) between the tip and sample. As we can see in the Figure 1l,m,n, the apparent height of samples 1 and 5 are 19.3 nm (Figure 1n) and 6.9 nm

• on the sample surface. The electrostatic attractive force superposes on the van der Waals force between the tip and sample so that the SPFM imaging gives a higher apparent height than the topographic height of nanomaterials when the dielectric constant of the nanomaterials is larger than the

Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations

• Jaison Jeevanandam,
• Ahmed Barhoum,
• Yen S. Chan,
• Alain Dufresne and
• Michael K. Danquah

Beilstein J. Nanotechnol. 2018, 9, 1050–1074, doi:10.3762/bjnano.9.98

• capillary attractive forces and molecular interactions [230] or van der Waals interactions leads to adhesion [231]. This may be due to the production of secretory fluids in the contact area by some animals (insects) [232][233][234], whereas others do not (spiders, geckos) [235][236], which makes the basic

• force in the physical form contribute to their adhesion. In recent reports, the reason for adhesion of gecko setae is due to van der Waals interaction through strong evidence [237] and rejects the capillary adhesion mechanisms. It was predicted that application of contact mechanics may help in smaller

• structures in their feet that are aligned in a series of a small ridges with a projection of 200 nm width in each hair. This increases the total surface area of gecko feet and leads to a van der Waals interaction mediated strong surface adhesion [241]. Similarly, the crystalline composite of CaCO3 crystals

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• based on density functional theory [68][69] as implemented in the SIESTA code [70][71]. For the exchange-correlation potential, we used the van der Waals density functional (vdW-DF) [72][73] as implemented on the Román-Pérez and Soler scheme [74]. We employed norm-conserving Troullier–Martins [75

A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide

• Shahreen Binti Izwan Anthonysamy,
• Syahidah Binti Afandi,
• Mehrnoush Khavarian and
• Abdul Rahman Bin Mohamed

Beilstein J. Nanotechnol. 2018, 9, 740–761, doi:10.3762/bjnano.9.68

• mechanism suggests that only one molecule will adsorb on the catalyst surface and the second molecule will react with it directly from the gas phase (van der Waals force) to form a new product. Liu et al. [22] found that the Fe2O3 catalyst forms amide species (NH2−) in the presence of NH3 on the Lewis acid

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

• Kaliappan Muthukumar,
• Harald O. Jeschke and
• Roser Valentí

Beilstein J. Nanotechnol. 2018, 9, 711–720, doi:10.3762/bjnano.9.66

• parameterization of Perdew, Burke and Ernzerhof [20] was used as approximation for the exchange and correlation functional. In addition, dispersion corrections [21] were used to simulate the long-range van der Waals interactions. All calculations were performed in the scalar relativistic approximation. A kinetic

The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

• Egor A. Kolesov,
• Mikhail S. Tivanov,
• Olga V. Korolik,
• Olesya O. Kapitanova,
• Xiao Fu,
• Hak Dong Cho,
• Tae Won Kang and
• Gennady N Panin

Beilstein J. Nanotechnol. 2018, 9, 704–710, doi:10.3762/bjnano.9.65

• plots. This observation can be explained by substrate-induced strain in as-grown graphene (leading to greater overall peak positions [14]): The van der Waals graphene–substrate interaction model may not be fully applicable for this case due to the possibility of chemical bonds present between graphene

• close to the case of graphene transferred to Cu. Being a van der Waals structure on the scale of adsorption effects (in terms of interlayer bonding), bilayer graphene is known to have a slightly greater energy barrier for the adsorption process [26]. However, adsorption in this case can also lead to at

Tuning adhesion forces between functionalized gold colloidal nanoparticles and silicon AFM tips: role of ligands and capillary forces

• Sven Oras,
• Sergei Vlassov,
• Marta Berholts,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2018, 9, 660–670, doi:10.3762/bjnano.9.61

• NPs and silicon tip depending on the nature of the tail functional group. The dependence of the adhesion on ligand density for different thiols with identical functional tail-group was also demonstrated. The calculated contribution of the van der Waals (vdW) forces between particles was in good

Facile phase transfer of gold nanorods and nanospheres stabilized with block copolymers

• Yaroslav I. Derikov,
• Georgiy A. Shandryuk,
• Raisa V. Talroze,
• Alexander A. Ezhov and
• Yaroslav V. Kudryavtsev

Beilstein J. Nanotechnol. 2018, 9, 616–627, doi:10.3762/bjnano.9.58

• due to van der Waals interactions, so their stabilization requires the use of bulky surfactant molecules [24][25][26] or polymers with a strongly binding groups via grafting-to [27][28], grafting-from [4] and grafting-around [29] approaches, hyperbranched polymers [30] or polymers with a significant

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• method was used to model the van der Waals interactions that may occur in the simulation. All calculations are performed using the well-known siesta package [33][34]. Results and Discussion The crystalline structure and phase purity of the dried black MoS2 powder were investigated using XRD. As

• electron-donor gas molecules. This increment in the electron carrier concentration can reduce the resistivity of the device. When the gas leaves the chamber, the molecules which transfer the charge from weak van der Waals interaction leave the MoS2 layer and the concentration of the carrier reduces, hence

• differences, we performed a simulation study on the pristine monolayer and similar surface with sulfur vacancy of MoS2 in the presence of xylene and methanol molecules. Xylene shows almost no interaction with pristine MoS2 while a van der Waals interaction happens in the case of sulfur vacancy, which leads to

Single-step process to improve the mechanical properties of carbon nanotube yarn

• Maria Cecilia Evora,
• Xinyi Lu,
• Nitilaksha Hiremath,
• Nam-Goo Kang,
• Kunlun Hong,
• Roberto Uribe,
• Gajanan Bhat and
• Jimmy Mays

Beilstein J. Nanotechnol. 2018, 9, 545–554, doi:10.3762/bjnano.9.52

• ). The CNT yarn treated with AN and irradiation showed a rougher surface. The CNT yarn treated with AA exhibited a smoother appearance but wavy extensions protrude from the surface as shown in Figure 6. This is probably related to hydrophobic interactions, van der Waals and capillary force interactions

• between the aligned MWCNTs. The main force that keeps them together is van der Waals forces, which is a weak force. On the other hand, the FIB image of the PAN sample (Figure 5d,e) shows a higher density than untreated yarn (Figure 4c,d), which may be attributed to simultaneous grafting and crosslinking

Engineering of oriented carbon nanotubes in composite materials

• Razieh Beigmoradi,
• Abdolreza Samimi and
• Davod Mohebbi-Kalhori

Beilstein J. Nanotechnol. 2018, 9, 415–435, doi:10.3762/bjnano.9.41

• bonds and hydrophobic interactions and the positively charged PDDA bonds with the PSS/MWCNT layer via electrostatic and van der Waals forces. This scheme is illustrated in Figure 12. Inert gas flow In this method, the CNTs are arranged by flowing a gas along the substrate. The CNT suspension is

• , van der Waals) also plays a decisive role to enhance the uniformity of the CNT dispersion into the polymer matrix [136]. Therefore, to obtain the desired properties of CNT/polymer composites, such as the thermal, mechanical and electrical properties [8][10][137], the characterization of surface

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

• thousand times larger than forces that are proportional to volume, making inertial forces negligible. At the nanoscale, van der Waals, capillary and electrostatic forces become the governing factors. It is important to note, that with the decrease of the size scale, breakdown of the predictions of

• attractive (van der Waals (FvdW) and electrostatic (Felec)) and repulsive elastic (Felas) forces acting on a movable switching element in single (Figure 1a) or double-clamped (Figure 1c) position, and initially separated from the contact electrode by a distance z. The operation principle of a NEM switch can

• the van der Waals (vdW) energy, Eelas is the elastic energy and Eelec is the electrostatic energy. An example of potential energy diagrams for the switching element–electrode interactions is shown in Figure 2a [13]. At low or no electrostatic field applied between the switching element and electrode

Gas-sensing behaviour of ZnO/diamond nanostructures

• Marina Davydova,
• Alexandr Laposa,
• Jiri Smarhak,
• Alexander Kromka,
• Neda Neykova,
• Josef Nahlik,
• Jiri Kroutil,
• Jan Drahokoupil and
• Jan Voves

Beilstein J. Nanotechnol. 2018, 9, 22–29, doi:10.3762/bjnano.9.4

• of X- and Z-axis and the electrostatic stability of the ZnO surface. Moreover, it should be pointed out that the structure was simulated without molecular mechanical calculations. It was found that the NO2 molecule is non-covalently bonded to the metal oxide surface atoms and van der Waals forces

• occur between gas molecule and ZnO surface [40]. Therefore, the distance between NO2 molecule and ZnO layer is set according to the van der Waals radius of the respective atoms. The same approach was applied to the ZnO/diamond interlayer distance. The double-zeta polarized basis set was used for all

The rational design of a Au(I) precursor for focused electron beam induced deposition

• Ali Marashdeh,
• Thiadrik Tiesma,
• Niels J. C. van Velzen,
• Sjoerd Harder,
• Remco W. A. Havenith,
• Jeff T. M. De Hosson and
• Willem F. van Dorp

Beilstein J. Nanotechnol. 2017, 8, 2753–2765, doi:10.3762/bjnano.8.274

• considered to interact when the Au–Au distance is shorter than 3.7 Å, i.e., twice the van der Waals radius for Au. The aurophilic bond generally displays lengths of circa 3.0–3.4 Å and bond strengths of circa 7–12 kcal/mol [65]. Relativistic effects amount to 28% of the binding energy and originate almost

Dry adhesives from carbon nanofibers grown in an open ethanol flame

• Christian Lutz,
• Julia Syurik,
• C. N. Shyam Kumar,
• Christian Kübel,
• Michael Bruns and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 2719–2728, doi:10.3762/bjnano.8.271

• nearly every surface and adhere to it due to van der Waals forces, allowing the gecko to stick and climb nearly every surface [19][20][21]. Mimicking these nanostructures can lead to high performance dry adhesives with a great range of possible applications in attachment systems of climbing robots [22

Interface conditions of roughness-induced superoleophilic and superoleophobic surfaces immersed in hexadecane and ethylene glycol

• Yifan Li,
• Yunlu Pan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2017, 8, 2504–2514, doi:10.3762/bjnano.8.250

• colloidal AFM tip. Then the probe was driven towards the surface immersed in liquid at a certain driving velocity. By analyzing the force exerted on the probe, which mainly includes hydrodynamic forces, electrostatic forces, van der Waals force and Stokes force, the boundary slip can be calculated [12][18

Adsorption of iron tetraphenylporphyrin on (111) surfaces of coinage metals: a density functional theory study

• Hao Tang,
• Nathalie Tarrat,
• Véronique Langlais and
• Yongfeng Wang

Beilstein J. Nanotechnol. 2017, 8, 2484–2491, doi:10.3762/bjnano.8.248

• The adsorption of the iron tetraphenylporphyrin (FeTPP) molecule in its deckchair conformation was investigated on Au(111), Ag(111) and Cu(111) surfaces by performing spin-polarized density functional theory (DFT) calculations taking into account both van der Waals (vdW) interaction and on-site

• gradient approximation [33][34] were employed. The van der Waals dispersive interaction correction according to Grimme's DFT-D2 method [35] was considered for inter- and intra-molecular interactions as well as molecule–surface interactions. The C6 parameter was optimized in a model system on Au(111) in

Involvement of two uptake mechanisms of gold and iron oxide nanoparticles in a co-exposure scenario using mouse macrophages

• Dimitri Vanhecke,
• Dagmar A. Kuhn,
• Dorleta Jimenez de Aberasturi,
• Sandor Balog,
• Ana Milosevic,
• Dominic Urban,
• Diana Peckys,
• Niels de Jonge,
• Wolfgang J. Parak,
• Alke Petri-Fink and
• Barbara Rothen-Rutishauser

Beilstein J. Nanotechnol. 2017, 8, 2396–2409, doi:10.3762/bjnano.8.239

• ]. Therefore, the occurrence of NP diffusion through pores in the membrane as well as passive uptake by van der Waals or steric interactions (subsumed as adhesive interactions) [25] cannot be excluded. The majority of uptake studies were conducted with one defined NP type only. However, since humans are more

Optical contrast and refractive index of natural van der Waals heterostructure nanosheets of franckeite

• Patricia Gant,
• Foad Ghasemi,
• David Maeso,
• Carmen Munuera,
• Elena López-Elvira,
• Riccardo Frisenda,
• David Pérez De Lara,
• Gabino Rubio-Bollinger,
• Mar Garcia-Hernandez and
• Andres Castellanos-Gomez

Beilstein J. Nanotechnol. 2017, 8, 2357–2362, doi:10.3762/bjnano.8.235

• visible spectrum through a fit of the acquired spectra to a model based on the Fresnel law. Keywords: complex refractive index; franckeite; optical contrast; optical identification; van der Waals heterostructure; Introduction Mechanical exfoliation is a very powerful technique to produce a large variety

• is one of the few known examples of a naturally occurring van der Waals heterostructure (another example of these materials is the cylindrite [19], see Supporting Information File 1). Unlike most of the studied heterostructures (that are manually assembled layer-by-layer) franckeite, in its natural

• form, presents alternating SnS2-like and PbS-like layers stacked on top of each other (Figure 1), overcoming the major drawbacks of synthetic van der Waals heterostructures: the difficulty to align the crystal lattices of the different materials with atomic accuracy and the presence of ambient

Material property analytical relations for the case of an AFM probe tapping a viscoelastic surface containing multiple characteristic times

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2230–2244, doi:10.3762/bjnano.8.223

• excitation suddenly imposed during the impact. The third term is the relaxation modulus, and the fourth term is the adhesive portion of the van der Waals (vdW) interaction, in which HA is the Hamaker constant, R is the radius of the cylindrical punch, and a0 is the interatomic distance (ca. 0.2 nm) [39]. In

• method [39]. Here the total attractive van der Waals potential (EvdW) was calculated for the specific case of a flat-end cylindrical punch interacting with a flat semi-infinite half-space, and subsequently the interaction force was obtained through differentiation: For the adhesion portion during

Preparation and characterization of polycarbonate/multiwalled carbon nanotube nanocomposites

• Claudio Larosa,
• Niranjan Patra,
• Marco Salerno,
• Lara Mikac,
• Remo Merijs Meri and
• Mile Ivanda

Beilstein J. Nanotechnol. 2017, 8, 2026–2031, doi:10.3762/bjnano.8.203

• used p-xylene and dichloromethane solvent to mix MWCNTs and prevent their agglomeration induced by strong van der Waals forces. Previous work carried out on PC/MWCNT composites with focus on the mechanical properties showed an increase in the storage modulus obtained from indentation measurements at

• solvent helps to overcome the van der Waals interaction in the nanotubes, eventually leading to better dispersion. Figure 3 shows the normalized FTIR absorption spectra of principal absorbance bands of the investigated PC/MWCNT nanocomposite films. FTIR spectroscopy demonstrated to be a useful tool to

A systematic study of the controlled generation of crystalline iron oxide nanoparticles on graphene using a chemical etching process

• Peter Krauß,
• Jörg Engstler and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2017, 8, 2017–2025, doi:10.3762/bjnano.8.202

• dense growth of CNTs, yet random areas of VACNTs still exist under these growth conditions (Figure S8, Supporting Information File 1). We speculate that in areas where VACNT growth occurs, the catalyst particle size and density are in the range that a dense growth, supported by van der Waals