Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy

• Majid Fazeli Jadidi,
• Umut Kamber,
• Oğuzhan Gürlü and
• H. Özgür Özer

Beilstein J. Nanotechnol. 2018, 9, 2953–2959, doi:10.3762/bjnano.9.274

• explicable with the additional effect of electrostatic forces in the experiments. The sample bias voltage values used in the experiments (up to 500 mV) would result in considerable electrostatic force between the tip and the sample. Also, tips with relatively large cone angles would result in van der Waals

• der Waals (vdW) interaction for a small tip structure only, but not the electrostatic force. The discrepancy in the value of the maximum attractive force and the interaction range of the total measured force, which are much larger than the values derived from the theoretical calculations, is

• maximum attractive force is about 7 nN for both sites. Ondracek et al. calculated the maximum attractive force between a tungsten tip and carbon and hollow sites on graphene to be about 2 nN [25]. However, in their calculations they took into account the short-range interaction and the longer-range van

In situ characterization of nanoscale contaminations adsorbed in air using atomic force microscopy

• Jesús S. Lacasa,
• Lisa Almonte and
• Jaime Colchero

Beilstein J. Nanotechnol. 2018, 9, 2925–2935, doi:10.3762/bjnano.9.271

• contamination; tip cleaning; tip–sample interaction; van der Waals interaction; Introduction Surface science is fundamental to understand many processes in industrial applications, environmental science, biology, medicine and phenomena such as self-assembly [1], friction [2][3] and wetting [4]. In any study

• more detail elsewhere [42], data can be acquired in the (true) non-contact regime (nc-DAFM), where only van der Waals and electrostatic interaction is present. In this work we will assume that the tip–sample system can be described by a metallic tip interacting electrostatically with a metallic sample

• ) = πε0R/d2. Then, the total frequency-shift induced by the tip–sample interaction is: where the first term containing the Hamaker constant A describes the van der Waals interaction and the second term describes the electrostatic interaction. We note that the chemical composition of the sample will

Layered calcium phenylphosphonate: a hybrid material for a new generation of nanofillers

• Kateřina Kopecká,
• Ludvík Beneš,
• Klára Melánová,
• Vítězslav Zima,
• Petr Knotek and
• Kateřina Zetková

Beilstein J. Nanotechnol. 2018, 9, 2906–2915, doi:10.3762/bjnano.9.269

• differ with the metal and organic group incorporated in their structure, the main characteristic remains the same: a strong in-plane bonding in combination with weak van der Waals interactions between the planes. This arrangement enables their use as a host material in intercalation chemistry and as a

• precursor for the preparation of nanosheets by exfoliation. Exfoliation is a process whereby thin sheets of material are completely separated from the bulk. This happens when cohesive forces between the adjacent planes, which are usually caused by van der Waals interactions, are overcome. Mechanical or

Nanostructure-induced performance degradation of WO₃·nH₂O for energy conversion and storage devices

• Zhenyin Hai,
• Mohammad Karbalaei Akbari,
• Zihan Wei,
• Danfeng Cui,
• Chenyang Xue,
• Hongyan Xu,
• Philippe M. Heynderickx,
• Francis Verpoort and
• Serge Zhuiykov

Beilstein J. Nanotechnol. 2018, 9, 2845–2854, doi:10.3762/bjnano.9.265

• in a faster performance degradation, due to its weak interlayer van der Waals forces, even though it outranks the 3D network structure in terms of improved electronic properties. The structural transformation of 2D layered WO3·nH2O into 3D nanostructures is observed via ex situ Raman measurements

• layered transition metal oxides. Keywords: 2D layered oxides; interlayer water; van der Waals interaction; WO3·nH2O; Introduction Within the less than 20 years since the successful exfoliation of atomically thin graphene, 2D layered nanomaterials have been contributing greatly to the advances of

• , revealing that the weakness of layered 2D WO3·nH2O originates from weak interlayer van der Waals interactions. The faster performance degradation in electrochemical tests of 2D layered WO3·nH2O further indicated the structural instability of 2D nanostructures compared to 3D nanostructures. The structural

Graphene-enhanced metal oxide gas sensors at room temperature: a review

• Dongjin Sun,
• Yifan Luo,
• Marc Debliquy and
• Chao Zhang

Beilstein J. Nanotechnol. 2018, 9, 2832–2844, doi:10.3762/bjnano.9.264

• sensors based on rGO exhibited a rapid and high response to target gas at room temperature. However, these sensors show a common shortage. Since the binding force between graphene and gas molecules is van der Waals force or even covalent bonds [6], the recovery time is too long, sometimes recovery is not

Accurate control of the covalent functionalization of single-walled carbon nanotubes for the electro-enzymatically controlled oxidation of biomolecules

• Naoual Allali,
• Veronika Urbanova,
• Mathieu Etienne,
• Xavier Devaux,
• Martine Mallet,
• Brigitte Vigolo,
• Jean-Joseph Adjizian,
• Chris P. Ewels,
• Sven Oberg,
• Alexander V. Soldatov,
• Edward McRae,
• Yves Fort,
• Manuel Dossot and
• Victor Mamane

Beilstein J. Nanotechnol. 2018, 9, 2750–2762, doi:10.3762/bjnano.9.257

• of water. Once water was added, van der Waals and dipolar interactions between the water molecules and the ETG chain effectively blocked chain flexion and maintained the ferrocene unit at a distance of over 6.41 Å from the tube surface throughout the simulation (Figure 12B). Even for HIPCO-FcETG2

Two-dimensional semiconductors pave the way towards dopant-based quantum computing

• José Carlos Abadillo-Uriel,
• Belita Koiller and
• María José Calderón

Beilstein J. Nanotechnol. 2018, 9, 2668–2673, doi:10.3762/bjnano.9.249

• band gaps range from millielectronvolts to a few electronvolts. They can also be stacked in van der Waals heterostructures [22][24][25] favoring miniaturization and device integration. Incorporation of dopants affects the properties of isolated or stacked monolayers [26][27], as they do in bulk systems

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

• Weibin Wu,
• Christian Lutz,
• Simon Mersch,
• Richard Thelen,
• Christian Greiner,
• Guillaume Gomard and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2018, 9, 2618–2627, doi:10.3762/bjnano.9.243

• separating sand particles from the dense scales thereby reducing van der Waals forces [16]. Even a glycosylated technical surface showed a reduced granular friction coefficient [16]. Here, we analyse the tribological properties of single scales of sandfish (S. scincus) by atomic force microscopy and

Improved catalytic combustion of methane using CuO nanobelts with predominantly (001) surfaces

• Qingquan Kong,
• Yichun Yin,
• Bing Xue,
• Yonggang Jin,
• Wei Feng,
• Zhi-Gang Chen,
• Shi Su and
• Chenghua Sun

Beilstein J. Nanotechnol. 2018, 9, 2526–2532, doi:10.3762/bjnano.9.235

• sampled by the gamma point based on our tests. The k-point and cutoff energy were tested with higher computational settings, as 3 × 3 × 1 and 450 eV, leading to the difference of less than 0.1 eV in terms of the adsorption energies. The van der Waals (vdW) interaction was considered with the use of the

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• . But studies of atomically flat surfaces in vacuum demonstrate that the actual origin of friction is at the atomic scale. The friction force results from the sum of atomic-scale forces, including all kinds of interactions including Coulombic forces, covalent bonding and van der Waals forces. As a

Synthesis of hafnium nanoparticles and hafnium nanoparticle films by gas condensation and energetic deposition

• Irini Michelakaki,
• Nikos Boukos,
• Dimitrios A. Dragatogiannis,
• Spyros Stathopoulos,
• Costas A. Charitidis and
• Dimitris Tsoukalas

Beilstein J. Nanotechnol. 2018, 9, 1868–1880, doi:10.3762/bjnano.9.179

• van der Waals interaction between NPs and substrate [62].When increasing the substrate voltage, the strengthening is attributed to the high temperatures that arise locally when the NPs impact on the substrate [63]. Due to the high temperatures lead to partial coalescence of the NPs and neck formation

Improving the catalytic activity for hydrogen evolution of monolayered SnSe_2(1−x)S_2x by mechanical strain

• Sha Dong and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2018, 9, 1820–1827, doi:10.3762/bjnano.9.173

• synthesized by using traditional mechanical exfoliation techniques [24][25] because of the weak van der Waals (vdW) interactions between layers. These mono- and few-layer SnX2 (X = S, Se) compounds are expected to be widely used in the fields of water splitting [26], high-speed photodetection [27

Uniform cobalt nanoparticles embedded in hexagonal mesoporous nanoplates as a magnetically separable, recyclable adsorbent

• Can Zhao,
• Yuexiao Song,
• Tianyu Xiang,
• Wenxiu Qu,
• Shuo Lou,
• Xiaohong Yin and
• Feng Xin

Beilstein J. Nanotechnol. 2018, 9, 1770–1781, doi:10.3762/bjnano.9.168

• in their framework has become a quite possible strategy for introduction of metal nanoparticles onto the support. The metal cations might migrate across the interlayer space during the thermal reduction process at high temperature due to the weak van der Waals forces between the interlayer of the LDH

Free-radical gases on two-dimensional transition-metal disulfides (XS₂, X = Mo/W): robust half-metallicity for efficient nitrogen oxide sensors

• Chunmei Zhang,
• Yalong Jiao,
• Fengxian Ma,
• Sri Kasi Matta,
• Steven Bottle and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1641–1646, doi:10.3762/bjnano.9.156

• conditions, a vacuum layer with a thickness of more than 20 Å was set to minimize artificial interactions between neighboring layers. A dispersion correction of total energy (DFT-D3 method) [37] is used to incorporate the long-range van der Waals interaction. The structures are fully relaxed until energy and

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