Graphene–polymer coating for the realization of strain sensors

• Carmela Bonavolontà,
• Carla Aramo,
• Massimo Valentino,
• Giampiero Pepe,
• Sergio De Nicola,
• Gianfranco Carotenuto,
• Angela Longo,
• Mariano Palomba,
• Simone Boccardi and
• Carosena Meola

Beilstein J. Nanotechnol. 2017, 8, 21–27, doi:10.3762/bjnano.8.3

• poly(methyl methacrylate) (PMMA). The good adhesion to the PMMA surface, combined with the shear stress, allows a uniform and continuous spreading of the graphite nanocrystals, resulting in a very uniform graphene multilayer coating on the substrate surface. The fabrication process is simple and yields

• surface, combined with the shear stress, allowed for the uniform and continuous spreading of the graphite nanocrystals on the substrate surface with formation of a very uniform graphene multilayer coating. The electrical response to the mechanical deformation of a strain sensor is generally quantified by

• ) film to achieve a very uniform coating of the substrate surface. The adhesion to the PMMA surface, combined with the applied shear stress, allowed a uniform and continuous spreading of the graphite nanocrystals on the substrate surface with formation of a very uniform graphene multilayer coating. The

When the going gets rough – studying the effect of surface roughness on the adhesive abilities of tree frogs

• Niall Crawford,
• Thomas Endlein,
• Jonathan T. Pham,
• Mathis Riehle and
• W. Jon P. Barnes

Beilstein J. Nanotechnol. 2016, 7, 2116–2131, doi:10.3762/bjnano.7.201

• abrasion of the pad epithelium. Here, we tested the effect of surface roughness on the attachment abilities of the tree frog Litoria caerulea. This was done by testing shear and adhesive forces on artificial surfaces with controlled roughness, both on single toe pads and whole animal scales. It was shown

• frictional shear stress (Figure 2A). Forces initially increased with roughness, with the largest shear stresses being measured on the 6 µm surface (30.1 ± 13.8 kPa; z = −5.1672, p < 0.00014). Shear stress values on the 15 µm surfaces were 18.48 ± 6.1 kPa, higher than the smooth values (z = −5.5663, p

• < 0.00014), but lower than the forces on the 6 µm surface. The shear stress measured on the largest roughnesses tested were at a consistent level of ca. 16 kPa, still higher than those measured on the smooth surface (e.g., comparing smooth to 100 µm, z = −5.5072, p < 0.00014). Adhesive forces (Figure 2B

A new approach to grain boundary engineering for nanocrystalline materials

• Shigeaki Kobayashi,
• Sadahiro Tsurekawa and
• Tadao Watanabe

Beilstein J. Nanotechnol. 2016, 7, 1829–1849, doi:10.3762/bjnano.7.176

• high-cycle fatigue may result from a rapid migration of low-angle boundaries involving some dislocation mechanisms and enhanced by segregated P atoms at finally resultant random boundaries along shear bands. The operating mechanism will be explained later in some detail. Figure 7 shows the

• fatigue. The cyclic stress-induced grain growth, accompanying the transformation of low-angle boundaries into the boundaries with higher misorientation angle, is associated with the evolution of a “diamond-shaped” grain structure along initially formed shear bands. This resulted in intergranular fatigue

• probably deformed by shear stress as in the case of a single crystal, because the persistent slip bands (PSBs) can continuously transfer across the low-angle boundaries [97]. The fatigue cracks preferentially nucleated along random boundaries whose boundary plane may almost correspond to the direction of

Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces

• Ana C. S. Alcântara,
• Margarita Darder,
• Pilar Aranda and
• Eduardo Ruiz-Hitzky

Beilstein J. Nanotechnol. 2016, 7, 1772–1782, doi:10.3762/bjnano.7.170

• in aqueous 80% (v/v) ethanol solution by vigorous stirring in a shear mixer (G2 model, Lomi) in order to properly disperse the clay. Solutions of zein (80% (v/v) ethanol/water) with different content in protein (30–1500 mg) were prepared in 50 mL, in order to achieve different weight proportions of

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube–silicon solar cells

• Benedikt W. Stolz,
• Daniel D. Tune and
• Benjamin S. Flavel

Beilstein J. Nanotechnol. 2016, 7, 1486–1491, doi:10.3762/bjnano.7.141

• aligned parallel to the surface. The recently developed process of dry shear aligning – in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the

• direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes. In this work, the fabrication and characterisation of carbon nanotube–silicon solar cells using such films is reported, and the

• photovoltaic performance of devices produced with and without dry shear aligning is compared. Keywords: absorbance; carbon nanotubes; current-voltage; dry shear aligning; order parameter; Introduction During the last decade or so, the potential benefits of using carbon nanotubes in solar cells has been

Deformation-driven catalysis of nanocrystallization in amorphous Al alloys

• Rainer J. Hebert,
• John H. Perepezko,
• Harald Rösner and
• Gerhard Wilde

Beilstein J. Nanotechnol. 2016, 7, 1428–1433, doi:10.3762/bjnano.7.134

• processing route is intense deformation and nanocrystals have been shown to develop in shear bands during the deformation process. Some controversy surrounded the idea of adiabatic heating in shear bands during their genesis, but specific experiments have revealed that the formation of nanocrystals in shear

• bands has to be related to localized deformation rather than thermal effects. A much less debated issue has been the spatial distribution of deformation in the amorphous alloys during intense deformation. The current work examines the hypothesis that intense deformation affects the regions outside shear

• bands and even promotes nanocrystal formation in those regions upon annealing. Melt-spun amorphous Al88Y7Fe5 alloy was intensely cold rolled. Microcalorimeter measurements at 60 °C indicated a slight but observable growth of nanocrystals in shear bands over the annealing time of 10 days. When the cold

The self-similarity theory of high pressure torsion

• Yan Beygelzimer,
• Roman Kulagin,
• Laszlo S. Toth and
• Yulia Ivanisenko

Beilstein J. Nanotechnol. 2016, 7, 1267–1277, doi:10.3762/bjnano.7.117

• of the process. The analysis shows that the main parameters of HPT are proportional to βq, with β being the angle of the anvil rotation. The meaning of the parameter q is: q = 0 for velocity and strain rate, q = 1 for shear strain and von Mises strain, q = n for stress, pressure and torque (n is the

• -similarity; severe plastic deformation; Introduction High pressure torsion (HPT) is a severe plastic deformation process, which is widely used for producing nanocrystalline metals and alloys [1][2][3]. The generally accepted theory of HPT is based on the assumptions of uniformity of simple shear deformation

• along the height of the specimen and that there is no slippage between the sample and the anvils. This theory gives a simple expression for the shear strain where β is the torsion angle of the anvil, r is the radial position and H is the height of the disc. However, a number of recent experiments and

Functional diversity of resilin in Arthropoda

• Jan Michels,
• Esther Appel and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2016, 7, 1241–1259, doi:10.3762/bjnano.7.115

• of hairs (setae) and applied shear force lead to the formation of a maximal real contact area without slippage within the contact [104]. This indicates that material flexibility is very important for the contact formation of adhesive pads. With a minimal normal load, flexible materials can create a

Reasons and remedies for the agglomeration of multilayered graphene and carbon nanotubes in polymers

• Rasheed Atif and
• Fawad Inam

Beilstein J. Nanotechnol. 2016, 7, 1174–1196, doi:10.3762/bjnano.7.109

• (TEM) and other high-resolution imaging tools. Wrinkles were observed in flat graphene sheets that occur due to the instability of the 2D lattice structure [13]. Wrinkling is a large and out-of-plane deflection caused by compression (in-plane) or shear, and it is usually found in thin and flexible

• uses the shear forces produced in the roll gaps to disperse, mix or homogenize viscous materials as shown in Figure 6. Each roll of the calender rotates at a different velocity. The first and the third roller, called feeding and apron roller, respectively, rotate in the same direction (say clockwise

• produced nanocomposite. The highly dispersed RGO–epoxy showed 52% improvement in fracture toughness (K1C) while poorly dispersed RGO–epoxy showed only 24% improvement in K1C. It shows that a better dispersion of RGO can be obtained using ball milling [13]. High-shear mixing and extrusion: High-shear mixing

Generalized Hertz model for bimodal nanomechanical mapping

• Aleksander Labuda,
• Marta Kocuń,
• Waiman Meinhold,
• Deron Walters and
• Roger Proksch

Beilstein J. Nanotechnol. 2016, 7, 970–982, doi:10.3762/bjnano.7.89

• ][5], force modulation [6][7], phase imaging [8][9], loss tangent imaging [10], friction force microscopy [11], creep compliance [12], shear modulation force microscopy [13], pulsed force microscopy [14] and torsional approaches [15]. These techniques can be broadly classified as either “parametric

Assembling semiconducting molecules by covalent attachment to a lamellar crystalline polymer substrate

• Rainhard Machatschek,
• Patrick Ortmann,
• Renate Reiter,
• Stefan Mecking and
• Günter Reiter

Beilstein J. Nanotechnol. 2016, 7, 784–798, doi:10.3762/bjnano.7.70

• semiconducting molecules. Results Nanocrystal analysis by AFM The model of an ideal CPE45 nanocrystal Nanocrystal dispersions were prepared via nanoprecipitation with the impact of shear forces generated by ultrasonication. By cryo-transmission electron microscopy (TEM) studies on the dispersions, a thickness of

Tight junction between endothelial cells: the interaction between nanoparticles and blood vessels

• Yue Zhang and
• Wan-Xi Yang

Beilstein J. Nanotechnol. 2016, 7, 675–684, doi:10.3762/bjnano.7.60

• blood vessels, which are the sites of phosphorylation of tight junction proteins (claudins, occludins, and ZO (Zonula occludens)) proteins, oxidative stress and shear stress. We propose a connection between the presence of nanoparticles and the regulation of the tight junction, which might be the key

• : (1) phosphorylation, (2) expression level of occludins and (3) shear stress. Research about the phosphorylation of occludins in rat brain capillaries after embolism showed that an increased level of tyrosine phosphorylation in occludins might play an important role regarding the disruption of the

• bile duct ligation researchers suggested a relationship between the time-dependent down-regulation of the occludin expression and a time-dependent increase of superoxide radical levels in the brain [68]. Another factor, shear stress, different from normal stressors, exerts a perpendicular force on the

In situ observation of deformation processes in nanocrystalline face-centered cubic metals

• Aaron Kobler,
• Christian Brandl,
• Horst Hahn and
• Christian Kübel

Beilstein J. Nanotechnol. 2016, 7, 572–580, doi:10.3762/bjnano.7.50

• additional local deviations from the sample bending, which appear as local, distinct rotations within the crystallites and in the vicinity of the grain boundaries (examples indicated by black boxes). A mismatch of the relative lattice rotation of neighboring grains needs to be accommodated as a shear

• deformation across the GB between the crystallites. The small angle rotation discontinuity at the grain boundary directly shows the operation of GB deformation processes, such as GB sliding and/or shear coupled GB motion. The small angle crystallite rotation highlighted in Figure 5b,c even shows the partial

Nanoscale effects in the characterization of viscoelastic materials with atomic force microscopy: coupling of a quasi-three-dimensional standard linear solid model with in-plane surface interactions

• Santiago D. Solares

Beilstein J. Nanotechnol. 2016, 7, 554–571, doi:10.3762/bjnano.7.49

• -mode using a single oscillation frequency in the small-amplitude regime. However, even in these most ideal situations, there still exist challenges associated with the shape of the tip, which does not necessarily impart uniform compressive strain, but may cause both compressive and shear strains with

• subsurface only considers tensile (compressive) strains, thus neglecting shear. This is common practice in AFM simulation, where 1D models are the norm (e.g., [2][3][10][12][13][14][16][28]), but neglects the fact that indentation of the tip into a soft material introduces surface curvature and subsurface 3D

Free vibration of functionally graded carbon-nanotube-reinforced composite plates with cutout

• Mostafa Mirzaei and
• Yaser Kiani

Beilstein J. Nanotechnol. 2016, 7, 511–523, doi:10.3762/bjnano.7.45

• analysis of CNTRC structures, examines the free vibration characteristics of plates containing a cutout that are reinforced with uniform or nonuniform distribution of carbon nanotubes. The first-order shear deformation plate theory is used to estimate the kinematics of the plate. The solution method is

• vibration and static response of laminated plates with FG-CNTRC layers using a mixed Navier-layerwise differential quadrature method. In this research, plates with all edges simply supported are considered. Natarajan et al. [12] applied a higher order shear and normal deformable plate formulation to study

• approach may be modified with the introduction of the efficiency parameters. Under such modification, Young’s modulus and the shear modulus of the composite media take the form: In this formula, the properties of the CNT are denoted by a superscript CN and that those belong to matrix are denoted by a

Contact-free experimental determination of the static flexural spring constant of cantilever sensors using a microfluidic force tool

• John D. Parkin and
• Georg Hähner

Beilstein J. Nanotechnol. 2016, 7, 492–500, doi:10.3762/bjnano.7.43

• experienced by the cantilever is due to plan-view-dependent drag as opposed to viscous shear, and the former is not significantly influenced by the presence of the tip. The reason for the observed hysteresis in the speed-dependent deflection (Figure 5) is not entirely clear. Some cantilevers showed no

Active multi-point microrheology of cytoskeletal networks

• Tobias Paust,
• Tobias Neckernuss,
• Lina Katinka Mertens,
• Ines Martin,
• Michael Beil,
• Paul Walther,
• Thomas Schimmel and
• Othmar Marti

Beilstein J. Nanotechnol. 2016, 7, 484–491, doi:10.3762/bjnano.7.42

• ; Introduction The dynamic shear modulus describes properties of polymer networks. It can be determined by recording and mathematically transforming the thermal motion of a particle embedded in a viscoelastic medium into the frequency domain. Since no external forces are applied to the motion of the particle

• , this method is named passive microrheology [1][2][3][4]. The resulting shear modulus shows the elastic and diffusive behavior of the investigated medium over the frequency range accessible by the measuring setup. This output is the result of different methods handling the unilateral Laplace transform

• [5][6][7]. By exciting a particle with an oscillating force, the shear modulus at a specific frequency can be determined by measuring the response of the particle. The motion of the particle also includes information about the damping and the viscosity of the surrounding medium. This method is known

Plasticity-mediated collapse and recrystallization in hollow copper nanowires: a molecular dynamics simulation

• Amlan Dutta,
• Arup Kumar Raychaudhuri and
• Tanusri Saha-Dasgupta

Beilstein J. Nanotechnol. 2016, 7, 228–235, doi:10.3762/bjnano.7.21

• system. The resolved shear load can thereby exceed the critical limit for producing the Shockley dislocations. The calculated shear-strain map indicates that the partial dislocations nucleate at the inner surface and propagate towards the outer periphery, thereby leaving behind trails of stacking faults

• highlighted, the partial dislocation at the boundary of an abruptly terminated stacking fault moves towards the outer surface and finally disappears during the recovery. Color-coded snapshots indicating the atomic shear strains are also given by the side. Snapshot of the nanostructure at 575 K temperature

Simultaneous cancer control and diagnosis with magnetic nanohybrid materials

• Reza Saadat and
• Franz Renz

Beilstein J. Nanotechnol. 2016, 7, 121–125, doi:10.3762/bjnano.7.14

• hence be assumed that a network (consisting of about three units in all spatial directions) of the MNP was obtained. We assume that bigger cluster units do not appear long enough to be detected due to shear forces destroying them. The cluster units are stable in a pH range from 13 to 4.5. At lower pH

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

• Elena Dellacasa,
• Li Zhao,
• Gesheng Yang,
• Laura Pastorino and
• Gleb B. Sukhorukov

Beilstein J. Nanotechnol. 2016, 7, 81–90, doi:10.3762/bjnano.7.10

• resonance frequency of the quartz crystal oscillator, A is the area of the electrode (0.205 cm2), ρq is the quartz density (2.648 g/cm3), and µq is its shear modulus (2.947·1011 g/cm·s2). The cleaned electrodes were immersed into aqueous solutions of PSS and PAH (2 mg/mL) for 15 min and PLL (5 mg/mL) for 30

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

• Urs Gysin,
• Thilo Glatzel,
• Thomas Schmölzer,
• Adolf Schöner,
• Sergey Reshanov,
• Holger Bartolf and
• Ernst Meyer

Beilstein J. Nanotechnol. 2015, 6, 2485–2497, doi:10.3762/bjnano.6.258

• presents a computer aided design (CAD) image of the beam deflection unit. The red arrows indicate the directions of motion of the adjustable parts of the unit. To align the beam of light onto the free end of the oscillating cantilever several shear piezo actuators allow for the movement of parts within the

• beam deflection unit. The focusing optics is placed on two shear piezo elements in order to allow for horizontal movement and to adjust the light beam across the width of the cantilever. Additionally, the beam splitter is placed on two shear piezo elements rotating the beam splitter and therefore align

• the light beam along the long axis of the cantilever. The reflected light from the cantilever irradiates directly onto the PSD with an adapted current to voltage converter (IV-converter). The detection unit, consisting of the PSD and IV-converter, may be moved by three 2D shear piezo elements

Electroviscous effect on fluid drag in a microchannel with large zeta potential

• Dalei Jing and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2015, 6, 2207–2216, doi:10.3762/bjnano.6.226

• ][14][15][16]. To characterize the EDL, zeta potential is defined, and it refers to the electrical potential at the shear plane separating the immobile fluid layer strongly attracted to the solid surface from the rest of the liquid. The magnitude of zeta potential is reported to be up to several

Lower nanometer-scale size limit for the deformation of a metallic glass by shear transformations revealed by quantitative AFM indentation

• Arnaud Caron and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2015, 6, 1721–1732, doi:10.3762/bjnano.6.176

• not discrete but continuous and localized around the indenter, and does not exhibit rate dependence. This contrasts with the observation of serrated, rate-dependent flow of metallic glasses at larger scales. Our results reveal a lower size limit for metallic glasses below which shear transformation

• mechanisms are not activated by indentation. In the case of metallic glass, we conclude that the energy stored in the stressed volume during nanometer-scale indentation is insufficient to account for the interfacial energy of a shear band in the glassy matrix. Keywords: AFM indentation; dislocation

• ; metallic glasses; metals; plasticity; shear transformation; Introduction Hardness testing has been widely applied by materials scientists and mechanical engineers to assess the mechanical properties of materials and to predict their behavior during machining processes or under tribological loading for the

Possibilities and limitations of advanced transmission electron microscopy for carbon-based nanomaterials

• Xiaoxing Ke,
• Carla Bittencourt and
• Gustaaf Van Tendeloo

Beilstein J. Nanotechnol. 2015, 6, 1541–1557, doi:10.3762/bjnano.6.158

• chirality (Figure 5a), a displacement map can be obtained (Figure 5c–d) at picometer precision, which further reveals the strain distribution. Strain induced by bending can be mapped in two dimensions, and further proposed to be a dominant non-uniform shear strain. The strain in the nanotube is associated

• instance, the evolution of defects (such as the shear strain present in CNTs as discussed in Section 3.1) along with the elastic/plastic deformation in CNT-reinforced composites under load can be well studied using similar techniques [109]. In contrast to the external stimuli, which are introduced through

Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• 5 MHz, Δm(g) is the mass change, A is the electrode area, ρq is the density of the quartz (2.65 g·cm-3), μq is the shear modulus (2.95 × 1011 dyn·cm−2), and the molecular weight of 1 is 280 g·mol−1. Thus, the surface coverage of 1 incorporated into LB films, obtained from Equation 1, is 0.98 × 10−9