Nonclassical dynamic modeling of nano/microparticles during nanomanipulation processes

• Moharam Habibnejad Korayem,
• Ali Asghar Farid and
• Rouzbeh Nouhi Hefzabad

Beilstein J. Nanotechnol. 2020, 11, 147–166, doi:10.3762/bjnano.11.13

• , respectively, expressed by [16] where FT is the pushing force, τss, τrs and τrt are the shear strength of contact in sliding on the substrate and rolling on the substrate and particle, respectively, μ represents the friction constants, As and At are the substrate–particle and particle–tip contact area

• χij are the symmetric part of couple stress and curvature tensors, respectively. Also, the relation for couple stress and curvature tensors is written as [27] where l is the material length scale parameter for considering the size effects, and G is the shear modulus. The displacement fields for the

An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

• Weili Liu,
• Hongjian Ni,
• Peng Wang and
• Yi Zhou

Beilstein J. Nanotechnol. 2020, 11, 24–40, doi:10.3762/bjnano.11.3

• were undertaken to evaluate the drag reduction performance of these bionic pipelines. It was found that the vortex ‘cushioning’ and ‘driving’ effects produced by the vortexes in the microgrooves were the main reason for obtaining a drag reduction effect. The shear stress of the microgrooved surface was

• complex conditions. Besides, these active antidrag methods require extra energy or may complicate the devices, which limits their application in engineering. Pressure loss mainly derives from the shear stress of a fluid flowing across the surface of a pipeline. The wall shear stress is expressed as where

• τ is the shear stress (Pa), μ is the dynamic viscosity of the fluid (Pa∙s); and du/dy is the velocity gradient (1/s). According to Equation 1, changing the turbulent boundary layer state in the vicinity of the wall for a decreased velocity gradient is an essential and appropriate measure to reduce

Design of a nanostructured mucoadhesive system containing curcumin for buccal application: from physicochemical to biological aspects

• Sabrina Barbosa de Souza Ferreira,
• Gustavo Braga,
• Évelin Lemos Oliveira,
• Jéssica Bassi da Silva,
• Hélen Cássia Rosseto,
• Lidiane Vizioli de Castro Hoshino,
• Mauro Luciano Baesso,
• Wilker Caetano,
• Craig Murdoch,
• Helen Elizabeth Colley and
• Marcos Luciano Bruschi

Beilstein J. Nanotechnol. 2019, 10, 2304–2328, doi:10.3762/bjnano.10.222

• , 0.08% (w/w) CUR were evaluated at 25 and 37 °C (Figure 6). The nonlinear behavior to shear stress due to the shear rate (non-Newtonian), resulting in structural changes, was maintained even after the incorporation of CUR in the polymer blends. Moreover, the addition of CUR in binary polymeric systems

• did not lead to a change in flow rheological profiles at 25 °C, whereas a slight decrease of shear stress was observed for systems evaluated at 37 °C. In this way, CUR did not change the structuring of the system. Conversely, the increase in temperature leads to an increase in shear stress due to the

• thermoresponsive properties of the preparations. Low hysteresis areas and different yield values could be observed in a prominent way at 37 °C, in comparison to systems investigated at 25 °C. Consequently, these systems showed shear thinning behavior flow, which is considered to be a desirable characteristic for

Microfluidics as tool to prepare size-tunable PLGA nanoparticles with high curcumin encapsulation for efficient mucus penetration

• Nashrawan Lababidi,
• Valentin Sigal,
• Aljoscha Koenneke,
• Konrad Schwarzkopf,
• Andreas Manz and
• Marc Schneider

Beilstein J. Nanotechnol. 2019, 10, 2280–2293, doi:10.3762/bjnano.10.220

• sub-micrometer particles, because it is a simple and straightforward technique, without the involvement of any chemical additives, and also does not require harsh formulation parameters, such as high energy input or mechanical shear stress (e.g., by sonification) [30][31]. Nonetheless, the preparation

High-tolerance crystalline hydrogels formed from self-assembling cyclic dipeptide

• Yongcai You,
• Ruirui Xing,
• Qianli Zou,
• Feng Shi and
• Xuehai Yan

Beilstein J. Nanotechnol. 2019, 10, 1894–1901, doi:10.3762/bjnano.10.184

• properties The rheological properties of hydrogels are key evaluation indicators for a variety of applications [50][51]. It is typically challenging for hydrogels based on linear peptides to maintain their original gel state for a long time or under shear force. Driven by a thermodynamic process, they tend

• hydrogel enhanced along with time. Strain-induced shear-thinning and self-healing abilities of the hydrogel were detected through continuous step changes of oscillatory strain between 500% and 1% (at a constant frequency of 1 rad s−1). Under a high magnitude strain (500%), the modulus of G’’ values

• fifth test cycle. As compared to that of 48 h, the C-WY hydrogel at 240 h showed a faster recovery speed. The strain-dependent oscillatory rheology results (at 240 h) showed a great anti-shear performance at stains ranging from about 0.1% to about 20%, indicating the shear-thinning behavior of the

Flexible freestanding MoS₂-based composite paper for energy conversion and storage

• Florian Zoller,
• Jan Luxa,
• Thomas Bein,
• Dina Fattakhova-Rohlfing,
• Daniel Bouša and
• Zdeněk Sofer

Beilstein J. Nanotechnol. 2019, 10, 1488–1496, doi:10.3762/bjnano.10.147

• flexible MoS2-based composite paper by high-energy shear force milling and simple vacuum filtration. This composite material combines high flexibility, mechanical strength and good chemical stability. Chronopotentiometric charge–discharge measurements were used to determine the capacitance of our paper

• the synthesis of a freestanding MoS2-based composite paper using a small addition of single-walled carbon nanotubes (SWCNTs) and shear-force milling in N-methyl-2-pyrrolidone (NMP). The paper was prepared simply by vacuum filtration of the slurry on top of a filter. The resulting material exhibits

• additional binders, conductive additives or a current collector. Results and Discussion Characterization of morphology, composition and mechanical properties The synthesized composite material based on MoS2 and SWCNTs was prepared by shear-force milling of MoS2 powder with SWCNTs. We then prepared a paper

Nanoscale spatial mapping of mechanical properties through dynamic atomic force microscopy

• Zahra Abooalizadeh,
• Leszek Josef Sudak and
• Philip Egberts

Beilstein J. Nanotechnol. 2019, 10, 1332–1347, doi:10.3762/bjnano.10.132

• mechanical properties of materials, the nanoscale mechanical properties, including elastic and shear moduli, can drastically differ from their bulk values. This results in opportunities to custom design or enhance bulk engineering materials with advances discovered through nanoscale interrogation [1]. Thus

• . Of course the advantages of dynamic AFM come at the expense that the lateral shear force between the tip and sample cannot be eliminated, making the technique inappropriate for weakly bonded samples. On the other hand, more variations of the experimental set up are possible for AFM, such as ultrahigh

Direct growth of few-layer graphene on AlN-based resonators for high-sensitivity gravimetric biosensors

• Jimena Olivares,
• Teona Mirea,
• Lorena Gordillo-Dagallier,
• Bruno Marco,
• José Miguel Escolano,
• Marta Clement and
• Enrique Iborra

Beilstein J. Nanotechnol. 2019, 10, 975–984, doi:10.3762/bjnano.10.98

• reached during the CVD growth of graphene (up to 650 °C). The active AlN films, purposely grown with the c-axis tilted, effectively excite shear modes displaying excellent in-liquid performance, with electromechanical coupling and quality factors of around 3% and 150, respectively, which barely vary after

• functionalization schemes also play an essential role. In fact, for a given design, the sensitivity not only depends on the density of the attached active receptors, but also on their distance to the device surface. For example, the interaction length of shear-mode resonators operating in liquid appears to be

• and patterned over the top electrode of the shear-mode SMRs. The active area of the resonators was subsequently functionalized using both covalent and non-covalent schemes that ended with the successful detection of antibodies without significant worsening of the resonator performance. Opposite to

Outstanding chain-extension effect and high UV resistance of polybutylene succinate containing amino-acid-modified layered double hydroxides

• Adam A. Marek,
• Vincent Verney,
• Christine Taviot-Gueho,
• Grazia Totaro,
• Laura Sisti,
• Annamaria Celli and
• Fabrice Leroux

Beilstein J. Nanotechnol. 2019, 10, 684–695, doi:10.3762/bjnano.10.68

• investigated and compared to filler-free PBS as well as LDH Mg2Al/nitrate as references. Both organo-modified LDHs exhibited a remarkable chain-extension effect for PBS with an outstanding increase in the zero-shear viscosity η0 for PBS–Mg2Al/PHE (two order of magnitude increase as compared to filler-free PBS

• sweeps from 0.1 to 100 rad s−1 and the gap between plates set at 1 mm. In all cases, the oscillatory shear stress amplitude was checked to ensure that measurements were performed inside the linear viscoelastic domain. The storage modulus (G’), loss modulus (G”) and tan δ (ratio of G” and G’) were

• fitting and extrapolation of the Cole–Cole representation to the x-axis (η′ at η″ = 0), the Newtonian zero-shear viscosity η0 can be calculated using Equation 1, which reflects even small changes in molecular mass. The effect of 5 wt % Mg2Al LDH filler on the PBS chain extension is presented as η”–η’ Cole

Topochemical engineering of composite hybrid fibers using layered double hydroxides and abietic acid

• Liji Sobhana,
• Lokesh Kesavan,
• Jan Gustafsson and
• Pedro Fardim

Beilstein J. Nanotechnol. 2019, 10, 589–605, doi:10.3762/bjnano.10.60

• material. Both bleached and unbleached pulps further undergo refining. Refining is a process in which mechanical compression and shear forces are applied to the intact wet fiber network in order to increase the surface exposure and surface area. In addition, it opens up fibrils on the surface, which

Mechanical and thermodynamic properties of Aβ₄₂, Aβ₄₀, and α-synuclein fibrils: a coarse-grained method to complement experimental studies

• Adolfo B. Poma,
• Horacio V. Guzman,
• Mai Suan Li and
• Panagiotis E. Theodorakis

Beilstein J. Nanotechnol. 2019, 10, 500–513, doi:10.3762/bjnano.10.51

• molecular understanding. Our approach allows a comparison of diverse elastic properties based on different deformations , i.e., tensile (YL), shear (S), and indentation (YT) deformation. From our analysis, we find a significant elastic anisotropy between axial and transverse directions (i.e., YT > YL) for

• the requirement of a different experimental setup, namely, the more involved sonification method [34]. Moreover, the experimental calculation of the shear modulus (S) can be realised by suspending the fibril between two beams and pressing the free part against the indenter, which gives rise to the

• , shear, and indentation processes. Mechanical and thermodynamics characterization through a CG model In our previous work [36], we have constructed a computational protocol for performing several types of mechanical deformation in silico (Figure 3). Such processes can be carried out at constant speed or

Graphene–graphite hybrid epoxy composites with controllable workability for thermal management

• Idan Levy,
• Eyal Merary Wormser,
• Maxim Varenik,
• Matat Buzaglo,
• Roey Nadiv and
• Oren Regev

Beilstein J. Nanotechnol. 2019, 10, 95–104, doi:10.3762/bjnano.10.9

• ) operated in cone and plate arrangements (stainless steel cone, with a 40 mm diameter and a 4° cone angle) at 25 °C. The shear rate was swept between 0.01–100 1/s, and each measurement was performed at steady-state flow at a shear rate of 0.01 1/s to extract the viscosity [51][68]. Functional thermal

• ). Single-filler composites: (a) TC and (b) viscosity and relative viscosity as functions of filler type and volume fraction at constant shear rate (0.1 1/s) and temperature of 25 °C. Each graph displays the fitting parameters. The solid lines in (a) are fits to the ROM model (Equation 1), and those in (b

• (at constant shear rate 0.1 [1/s], T = 25 °C) as a function of the graphite volume fraction. Each color represents a different constant GNP volume percent. The lines in (a) are fits to the ROM model (Equation 1), and those in (b), to the modified K–D model (Equation 2). The fitting parameters are

Pull-off and friction forces of micropatterned elastomers on soft substrates: the effects of pattern length scale and stiffness

• Peter van Assenbergh,
• Marike Fokker,
• Julian Langowski,
• Jan van Esch,
• Marleen Kamperman and
• Dimitra Dodou

Beilstein J. Nanotechnol. 2019, 10, 79–94, doi:10.3762/bjnano.10.8

• are present is referred to as the elastocapillary length l, which is defined as l = γ/μ, where γ is the surface tension of the substrate and μ is the elastic shear modulus of the substrate [26]. If the length scale of the microscale features is in the order of the elastocapillary length, indentation

• PVA-18, respectively. The elastocapillary length of PVA (defined as l = γPVA/μPVA [26], with surface tension γPVA ≈ 50 kPa [32] and elastic shear modulus μPVA ≈ 12 kPa for PVA-12) is in the order of 400 nm. Similarly, the elastocapillary length of PVA-18 is in the order of 300 nm. Pull-off forces of

A comparison of tarsal morphology and traction force in the two burying beetles Nicrophorus nepalensis and Nicrophorus vespilloides (Coleoptera, Silphidae)

• Liesa Schnee,
• Benjamin Sampalla,
• Josef K. Müller and
• Oliver Betz

Beilstein J. Nanotechnol. 2019, 10, 47–61, doi:10.3762/bjnano.10.5

• of pulling is well known in the attachment systems of insects, spiders and geckos [41]. Whereas in smooth systems, directionality results from a drop in contact area attributable to the flexibility of the pad, in hairy systems, both the contact area of each single hair and the higher shear stress

• local release might support shear-induced adhesion [46] and help to dose the secretion economically. In terms of the biological role, the higher attachment force in the pull direction might help the animals to climb effectively on a variety of structures such as plants and fur and might enable the males

• secretion in N. nepalensis compared with that of N. vespilloides [3]. Since under the dynamics of friction regimes, the generated shear stress is largely determined by the viscosity of the fluid [46], such higher viscosities might be responsible for the observed higher friction forces of N. nepalensis on

Contact splitting in dry adhesion and friction: reducing the influence of roughness

• Jae-Kang Kim and
• Michael Varenberg

Beilstein J. Nanotechnol. 2019, 10, 1–8, doi:10.3762/bjnano.10.1

• more easily to the surface waviness and by reducing the effective average peeling angle. These findings can be used to guide the development of biomimetic shear-actuated adhesives suitable for operation not only on smooth but also on rough surfaces. Keywords: biomimetics; contact splitting; gecko

• , regardless of the surface waviness, when the surface roughness increases. Second, splitting the wall-shaped microstructure in parallel to the shear direction helps to mitigate the negative effect of the increasing surface unevenness by allowing the split microstructure to adapt more easily to the surface

• waviness as well as by allowing it to reduce the effective average peeling angle. These findings can guide the development of biomimetic shear-actuated adhesives that are suitable for operation not only on smooth but also on rough surfaces. Experimental Microstructured surfaces with 140 µm high flaps

Ternary nanocomposites of reduced graphene oxide, polyaniline and hexaniobate: hierarchical architecture and high polaron formation

• Claudio H. B. Silva,
• Maria Iliut,
• Christopher Muryn,
• Christian Berger,
• Zachary Coldrick,
• Vera R. L. Constantino,
• Marcia L. A. Temperini and
• Aravind Vijayaraghavan

Beilstein J. Nanotechnol. 2018, 9, 2936–2946, doi:10.3762/bjnano.9.272

• -shear mixed at 7000 rpm for four times (15 min each). This procedure was used to avoid thermal degradation of the sample. The GO particles prepared by this method present flake sizes ranging from 5 to 30 μm [14][17], which are remarkably larger in comparison to GO reported in literature obtained by

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

• the exfoliation of CaPhP in an amount sufficient for incorporation into polymers involved using propan-2-ol with a strong shear force generated in a high-shear disperser. The filler was tested both in its unexfoliated and exfoliated forms for the preparation of polymer composites, for which a low

• more appropriate for treatment with hydrophobic compounds and, in comparison to pure ethanol, less expensive. The exfoliation of CaPhP in propan-2-ol was studied using various force actions starting with sonication, in addition to the combination with mild shear force, which is produced by pushing the

• particle dispersion through an injection needle by a peristaltic pump. Additionally, a strong shear force created by a high-shear disperser, where the velocity of dispersion was 5 m/s, was also applied. It was found out that the most suitable method for the exfoliation of calcium phenylphosphonate was the

The effect of flexible joint-like elements on the adhesive performance of nature-inspired bent mushroom-like fibers

• Elliot Geikowsky,
• Serdar Gorumlu and
• Burak Aksak

Beilstein J. Nanotechnol. 2018, 9, 2893–2905, doi:10.3762/bjnano.9.268

• kPa in shear and 110 kPa in pull-off stress in the gripping direction, which are twice and ten times higher than that in the releasing direction, respectively. A model to optimize the elastic modulus of the joint-like elements to enable sliding without peeling of the tips has been proposed. Keywords

• than vertically aligned [10]. This tilt, in addition to enhanced performance [11], equips the gecko with directional adhesion properties as shown by Autumn et al. [12]. When they tested setae using a load–drag–pull (LDP) experiment, they found that setae exhibit very high interfacial shear and tension

• when dragged along the direction of the tilt. Opposite to the tilt direction, low shear and compression was measured. They called this phenomenon frictional adhesion suggesting that the adhesive engagement between the gecko’s foot and the surface is enabled only when it pulls the foot in the direction

Low cost tips for tip-enhanced Raman spectroscopy fabricated by two-step electrochemical etching of 125 µm diameter gold wires

• Antonino Foti,
• Francesco Barreca,
• Enza Fazio,
• Cristiano D’Andrea,
• Paolo Matteini,
• Onofrio Maria Maragò and
• Pietro Giuseppe Gucciardi

Beilstein J. Nanotechnol. 2018, 9, 2718–2729, doi:10.3762/bjnano.9.254

• ] and shear-force microscopy (ShFM) [15] allow for chemical imaging of nanostructured materials, surfaces and (bio)molecular layers with a spatial resolution of 4–10 nm in ambient conditions [15][16], and can even reach atomic-level sensitivity in ultrahigh vacuum (UHV) [17][18][19]. Excellent reviews

Friction reduction through biologically inspired scale-like laser surface textures

• Johannes Schneider,
• Vergil Djamiykov and
• Christian Greiner

Beilstein J. Nanotechnol. 2018, 9, 2561–2572, doi:10.3762/bjnano.9.238

• ratio of the shear strength to the yield pressure of the softer metal [51]. Consequently, the tribological properties of the surface are strongly influenced by the subsurface material and the subsurface microstructure is strongly influenced by the plasticity and the nature of the corresponding

Evidence of friction reduction in laterally graded materials

• Roberto Guarino,
• Gianluca Costagliola,
• Federico Bosia and
• Nicola Maria Pugno

Beilstein J. Nanotechnol. 2018, 9, 2443–2456, doi:10.3762/bjnano.9.229

• time evolution obtained with FEM is also shown. In this case, the behaviour is strongly dependent on the thickness of the block. The time interval Δts needed to reach the static friction peak can be estimated starting from the shear stress τ = Gγ, where G is the shear modulus. If the shear deformation

• shear stress is reached (i.e., the static friction threshold). The first detachment of the sliding surface produces a detachment avalanche propagating towards the region with higher static friction threshold, as shown in Figure 5 (see also Supporting Information File 1). Analogous effects on the

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

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

• friction was recently observed for micro- and macroscale systems based on incommensurate sliding between graphene-covered spheres or “nanoscrolls” and substrates [76][77]. Also a decrease of friction shear stress with increasing number of layers has been observed for graphene over Si/SiO2 in vacuum

• , nitrogen, and air [78]. In addition, the shear strength and the interface adhesion energy for graphene on Si/SiO2 was proven to always exceed those of the graphene/Ni(111) interface [78]. The weakly lattice-mismatched graphite/hBN interface is also predicted to be promising for ultra-low-friction

• , only small particles adhere to the sublinear superlubric scaling law, while larger particles show a linear scaling between friction and area, equivalent to a constant shear stress [100]. This can be explained by an enhanced interaction between the Sb atoms and the substrate, as was found by ab initio

Defect formation in multiwalled carbon nanotubes under low-energy He and Ne ion irradiation

• Santhana Eswara,
• Jean-Nicolas Audinot,
• Brahime El Adib,
• Maël Guennou,
• Tom Wirtz and
• Patrick Philipp

Beilstein J. Nanotechnol. 2018, 9, 1951–1963, doi:10.3762/bjnano.9.186

• irradiation is part of these studies [2]. Irradiation-induced defects affect the elastic modulus and the tensile strength of CNTs [3]. For example, for multiwalled carbon nanotubes (MWCNTs), the presence of a small number of defects can increase the interlayer shear strength by several orders of magnitude [4

Nonlinear effect of carrier drift on the performance of an n-type ZnO nanowire nanogenerator by coupling piezoelectric effect and semiconduction

• Yuxing Liang,
• Shuaiqi Fan,
• Xuedong Chen and
• Yuantai Hu

Beilstein J. Nanotechnol. 2018, 9, 1917–1925, doi:10.3762/bjnano.9.183

• the neutral axis [31]. There are two factors to affect : mechanical shear deformations and accumulation of electric carriers. In general, shear deformations result in in-plane electric fields, which lead to carrier drift, while carrier accumulation results in diffusion. Because Δn/n0 is very small in

• the whole ZNW cross section in the linear regime, the largest variance rate of carrier concentration appears along the neutral axis because of the strongest shear deformation there. With increasing end force, the carrier accumulation increases such that there is a stronger nonlinear drift effect on

• difference is between the two endpoints of the x2-axis. Furthermore, the maximal positive potential amplitude is much lower than the maximal negative potential amplitude. In a bent piezoelectric semiconducting beam, two shear deformations produce two in-plane electric field components, E1 and E2. E1 is