Electrostatically actuated encased cantilevers

• Benoit X. E. Desbiolles,
• Gabriela Furlan,
• Adam M. Schwartzberg,
• Paul D. Ashby and
• Dominik Ziegler

Beilstein J. Nanotechnol. 2018, 9, 1381–1389, doi:10.3762/bjnano.9.130

• immersed in a viscous fluid. Quantitative measurements of stiffness, energy dissipation and tip–sample interactions using dynamic force sensors remain challenging due to spurious resonances of the system. Results: We demonstrate for the first time electrostatic actuation with a built-in electrode. Solely

• ≈ 90 μm) with a stiffness of k = 4 N·m−1 and a resonance frequency of f0 = 144.525 kHz and Qair = 36.5 is used. After immersion in water the quality factor remained high Qwater = 27.4, which enables high-resolution imaging with small interaction forces in liquids. Moreover, the clean electrostatic

• , the well-known expression for deflection of a uniformly loaded cantilever can be used. y(l) = ql4/(8EI). Inserting the static stiffness kstat = 3EI/l3 and q = Fdc/l we can express y(l) as a function of the capacitance gradient (C′), stiffness (kstat) and electrical potentials (Udc, UCPD, and Uac): To

Atomistic modeling of tribological properties of Pd and Al nanoparticles on a graphene surface

• Alexei Khomenko,
• Miroslav Zakharov,
• Denis Boyko and
• Bo N. J. Persson

Beilstein J. Nanotechnol. 2018, 9, 1239–1246, doi:10.3762/bjnano.9.115

• different temperatures, and showed how the static friction and contact stiffness depend on the contact area. They observed “contact aging” due to stress-aided, thermally activated atomic rearrangement processes. The term “contact aging” [6] is related to time-dependent atomic reconstructions at the

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

• force gradients cause shifts of Δf0 in the resonance frequency with a proportional relationship [30]: where k is the stiffness (or spring constant) of the cantilever. Resonance shifts also give rise to phase shifts, ∆φ, used to generate an image of the electric force gradients. In EFM imaging, the

Field-controlled ultrafast magnetization dynamics in two-dimensional nanoscale ferromagnetic antidot arrays

• Anulekha De,
• Sucheta Mondal,
• Sourav Sahoo,
• Saswati Barman,
• Yoshichika Otani,
• Rajib Kumar Mitra and
• Anjan Barman

Beilstein J. Nanotechnol. 2018, 9, 1123–1134, doi:10.3762/bjnano.9.104

• Oe−1, anisotropy field Hk = 0, saturation magnetization Ms = 860 emu cm−3, and exchange stiffness constant A = 1.3 × 10−6 erg cm−1. The material parameters were extracted by measuring the variation of precessional frequency (f) with bias magnetic field H for a Py thin film and by fitting them using

• Kittel formula, The exchange stiffness constant A is obtained from literature [39]. A pulsed field of peak value of 30 Oe, 10 ps rise/fall time and 20 ps pulse duration is used perpendicular to the sample plane, while a damping coefficient α = 0.008 is used during dynamic simulations. The experimentally

Imaging of viscoelastic soft matter with small indentation using higher eigenmodes in single-eigenmode amplitude-modulation atomic force microscopy

• Miead Nikfarjam,
• Enrique A. López-Guerra,
• Santiago D. Solares and
• Babak Eslami

Beilstein J. Nanotechnol. 2018, 9, 1116–1122, doi:10.3762/bjnano.9.103

• the first three flexural eigenmodes, using an individual equation of motion for each of them, all coupled through the tip–sample forces: Here zi, ki, Qi and refer to the i-th (with i = 1, 2, 3) eigenmode displacement, cantilever stiffness, cantilever quality factor, and resonance frequency

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

• stiffness, and as transparent layers used for heated, mist and ice-free, window panes [35]. By the end of 2003, Mercedes-Benz brought a NP-based clear coat into series production for both metallic and nonmetallic paint finishes. The coating increases the scratch resistance and enhances the gloss. Liquid

• nanocomposite. Nacre is designed by alternating micrometer-sized and sub-micrometer CaCO3 aragonite platelets, which are separated by a thin layer of bio-macromolecular “glue”. Enhanced stiffness, impact resistance, strength, and toughness are some of the mechanical properties that enable using nacre’s unique

Automated image segmentation-assisted flattening of atomic force microscopy images

• Yuliang Wang,
• Tongda Lu,
• Xiaolai Li and
• Huimin Wang

Beilstein J. Nanotechnol. 2018, 9, 975–985, doi:10.3762/bjnano.9.91

• AFM (Resolve, Bruker) in tapping mode with 96% setpoint value. A silicon cantilever (NSC36/ALBS, MikroMasch) with quoted stiffness of 0.6 N/m and tip radius of 8 nm was used for scanning. The scanning frequency and scanning angle were 2 Hz and 0°, respectively. Methods The step-by-step procedure of

Scanning speed phenomenon in contact-resonance atomic force microscopy

• Christopher C. Glover,
• Jason P. Killgore and
• Ryan C. Tung

Beilstein J. Nanotechnol. 2018, 9, 945–952, doi:10.3762/bjnano.9.87

• hydrophilic sample to show that hydrodynamic stiffness of an adsorbed water layer is a plausible explanation for scan speed-induced changes in the mechanical coupling of tip and sample. Theory In air, a native adsorbed layer of water exists on all surfaces. This layer, in some cases, is several nanometers

• stiffness is now a series combination of the fluid film stiffness kf and the material stiffness ks. There may also be additional damping effects introduced by the fluid film, which we would like to address in future research studies. For instance, it is known that the modulation of the tip–sample contact

• approximately as Vs/h3 for a simple two-dimensional slider model [20], where Vs is the velocity of the slider and h is the fluid gap height. Using this simple model, the hydrodynamic stiffness kf, which is proportional to ∂F/∂h (), varies approximately as Vs/h4. A very small fluid film layer can provide a very

Effect of microtrichia on the interlocking mechanism in the Asian ladybeetle, Harmonia axyridis (Coleoptera: Coccinellidae)

• Jiyu Sun,
• Chao Liu,
• Bharat Bhushan,
• Wei Wu and
• Jin Tong

Beilstein J. Nanotechnol. 2018, 9, 812–823, doi:10.3762/bjnano.9.75

• friction force of the DS–DS and VS–VS interactions is greater than that of the interaction between the VS and the abdomen. An additional explanation is that the vein is like a spring-loaded tape measure (that is, a carpenter’s tape) that can stabilize in the unfolded shape and confer sufficient stiffness

Lyapunov estimation for high-speed demodulation in multifrequency atomic force microscopy

• David M. Harcombe,
• Michael G. Ruppert,
• Michael R. P. Ragazzon and
• Andrew J. Fleming

Beilstein J. Nanotechnol. 2018, 9, 490–498, doi:10.3762/bjnano.9.47

• stiffness, elasticity and adhesiveness [10]. The acquisition of these observables requires tracking the amplitude and phase of additional frequencies of interest. These include higher harmonics of the fundamental frequency [11], higher flexural eigenmodes [12] and intermodulation products [13]. Higher

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

• , initiation of a current flow in the circuit (Figure 1b,d; Figure 2b) [13][15][32][40][68]. The jump-in voltage depends on the geometry of the device and the stiffness of the switching element. Switching from the on to off state (jump-off) occurs when the spring constant of the switching element exceeds the

• restoring force to the switching element in the 3T configuration reduces the requirements to elastic properties (stiffness) of the active element necessary for switching to the off position and allows reducing the jump-in voltage by diminishing the separation gap width. However, the gap cannot be smaller

• ] (Table 1). Thus, the contact area experiences higher current density than that inside the nanowire. This should be taken into account during analysis performed on NEM switch operation. The nanocontact area and stiffness of the switching element determine the on–off hysteresis width of a NEM switch. With

Anchoring of a dye precursor on NiO(001) studied by non-contact atomic force microscopy

• Sara Freund,
• Antoine Hinaut,
• Nathalie Marinakis,
• Edwin C. Constable,
• Ernst Meyer,
• Catherine E. Housecroft and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2018, 9, 242–249, doi:10.3762/bjnano.9.26

• ), using silicon cantilever (Nanosensors PPP-NCR, stiffness k = 20–30 N/m, resonance frequency f1 around 165 kHz, Qf1 factor around 30000, torsional frequency fTR around 1.5 MHz, and QTR factors around 100000) with compensated contact potential difference (CPD). Kelvin probe force microscopy was performed

Liquid-crystalline nanoarchitectures for tissue engineering

• Baeckkyoung Sung and
• Min-Ho Kim

Beilstein J. Nanotechnol. 2018, 9, 205–215, doi:10.3762/bjnano.9.22

• shown to result in enhanced cellular reorganization and facilitated tissue morphogenesis [55]. Mechanical stiffness of tissues is an important physical cue for modulating the behavior of adhered or embedded cells [56][57]. The LC architectures of ECM fibers may influence the functionality of target

• tissue by altering the elastic modulus of tissue [58]. Hard tissues Skeletal tissues are mineralized compact matrices of ordered biopolymers [59]. In vertebrates, bones consist of a dense mesophase of collagen fibrils [60], which has been believed to render mechanical stiffness to the skeletal tissues

• exhibited a high stiffness (570 kPa of Young’s modulus). Optical transparency of the dense collagen film in the visible spectral range could be maintained after formation of an epithelium of human corneal epithelial cells in vitro [87]. The cornea-like 3D plywood cholesteric organization of the collagen

Humidity-dependent wound sealing in succulent leaves of Delosperma cooperi – An adaptation to seasonal drought stress

• Olga Speck,
• Mark Schlechtendahl,
• Florian Borm,
• Tim Kampowski and
• Thomas Speck

Beilstein J. Nanotechnol. 2018, 9, 175–186, doi:10.3762/bjnano.9.20

• -sectional area (). The strain (ε) was calculated (Equation 4) as the fraction of the displacement (ΔL) divided by the original length (L0) of a tested sample. The elastic modulus, a measure of material stiffness, was calculated (Equation 5) from the slope of the initial (in good approximation) linear (i.e

A robust AFM-based method for locally measuring the elasticity of samples

• Alexandre Bubendorf,
• Stefan Walheim,
• Thomas Schimmel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2018, 9, 1–10, doi:10.3762/bjnano.9.1

• [7]. In Hurley and Turner’s [6] method, the stated equations for the computation of the normal sample stiffness by numerical methods (analytical expression for normal sample stiffness formulated by Bubendorf [8] and given in Supporting Information File 1) used to determine sample elasticity are based

• . Analysis of the force–displacement curve evidences the same relations with, however, a linear relation in the nonlinear domain of the frequency shift–displacement curves. This is explained by the low spring constant of the cantilever in comparison to the normal sample stiffness, beginning at a certain Z

• -displacement value. A good model of the cantilever in contact with the sample surface is two springs in series, k1 and ksample,norm, representing the spring constant of the cantilever and the normal sample stiffness (of constant value in the elastic phase), respectively (Figure 4a). As shown in Figure 4b, the

Material discrimination and mixture ratio estimation in nanocomposites via harmonic atomic force microscopy

• Weijie Zhang,
• Yuhang Chen,
• Xicheng Xia and
• Jiaru Chu

Beilstein J. Nanotechnol. 2017, 8, 2771–2780, doi:10.3762/bjnano.8.276

• cantilever deflection. Fn = knAn/Qn is the drive force. kn, An, Qn and ωn are the equivalent cantilever stiffness, amplitude, quality factor and angular resonance frequency, respectively. The interaction forces Fts, depend on the instantaneous gap, d, and they are simplified as, Here the attractive forces

• frequencies [33][34]. A higher elastic modulus, and therefore higher stiffness, will lead to a larger frequency shift, as schematically illustrated by the solid line, see Figure 4b. Similarly, a smaller elastic modulus causes a smaller frequency shift, as depicted by the dotted line. When the drive frequency

Exploring wear at the nanoscale with circular mode atomic force microscopy

• Olivier Noel,
• Aleksandar Vencl and
• Pierre-Emmanuel Mazeran

Beilstein J. Nanotechnol. 2017, 8, 2662–2668, doi:10.3762/bjnano.8.266

• range of cantilever stiffness. Experimental images as shown in Figure 3C and in Figure 4 also show that the material is not uniformly worn along the circular wear track. Wear is more intensive at some random locations of the material, evidencing heterogeneous wear (as in Figure 3C) or production of wear

• stiffness was 12 N/m and 0.4 N/m, respectively (as determined by the thermal noise method [27][28]). For each set of wear experiments, a unique AFM tip was used. After each measurement, force curves on a silicon wafer were performed to verify the state of the tip. Every data point represented in Figure 5

Robust nanobubble and nanodroplet segmentation in atomic force microscope images using the spherical Hough transform

• Yuliang Wang,
• Tongda Lu,
• Xiaolai Li,
• Shuai Ren and
• Shusheng Bi

Beilstein J. Nanotechnol. 2017, 8, 2572–2582, doi:10.3762/bjnano.8.257

• both air and DI water using a commercial AFM (Resolve, Bruker) in tapping mode with 96% setpoint value. Silicon cantilevers (NSC36/ALBS, MikroMasch) with a quoted stiffness of 0.6 N/m and tip radius of 8 nm were used for scanning. The measured resonance frequencies of the cantilever were 55 kHz and 16

Velocity dependence of sliding friction on a crystalline surface

• Christian Apostoli,
• Giovanni Giusti,
• Jacopo Ciccoianni,
• Gabriele Riva,
• Rosario Capozza,
• Rosalie Laure Woulaché,
• Andrea Vanossi,
• Emanuele Panizon and
• Nicola Manini

Beilstein J. Nanotechnol. 2017, 8, 2186–2199, doi:10.3762/bjnano.8.218

• . Recently published research also identified relations between dissipation peaks and the properties of a dispersion relation in a different model [63]. The present model can also be investigated in a spring-pulling scheme analogous to the Prandtl–Tomlinson model, to simulate the finite stiffness of an AFM

Magnetic properties of optimized cobalt nanospheres grown by focused electron beam induced deposition (FEBID) on cantilever tips

• Soraya Sangiao,
• César Magén,
• Darius Mofakhami,
• Grégoire de Loubens and
• José María De Teresa

Beilstein J. Nanotechnol. 2017, 8, 2106–2115, doi:10.3762/bjnano.8.210

• cylindrical magnetic microwire [11] (see inset of Figure 6a and the Experimental section for details on the setup). Due to the low stiffness (spring constant k = 6 mN/m) and high quality factor (2000 < Q < 4000 under vacuum) of the cantilever, its frequency accurately probes the magnetic force produced by the

High-stress study of bioinspired multifunctional PEDOT:PSS/nanoclay nanocomposites using AFM, SEM and numerical simulation

• Alfredo J. Diaz,
• Hanaul Noh,
• Tobias Meier and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2069–2082, doi:10.3762/bjnano.8.207

• free cantilever resonance frequency, is directly related to stiffness (larger stiffness leads to larger frequency and vice-versa) [49], while the quality factor maps the sample damping of the cantilever tip oscillation (greater dissipation leads to lower quality factor and vice-versa) [50]. The contact

• stiffness of polymers [54]. As expected, for both cases (thick and thin) the average measured contact-resonance frequency for the nanocomposites is higher than the frequency for PPSS, which means that the addition of the nanoclay results in a stiffer coating. Comparing thick and thin samples, it is observed

• that the average frequency is lower for the thin samples, but the trends are similar. The reduction of stiffness for the thin samples comes with a reduction in the conductivity (Figure 1b), which suggests that there is a different morphological arrangement in the thin samples. Since all the thin

Enhancement of mechanical and electrical properties of continuous-fiber-reinforced epoxy composites with stacked graphene

• Naum Naveh,
• Olga Shepelev and
• Samuel Kenig

Beilstein J. Nanotechnol. 2017, 8, 1909–1918, doi:10.3762/bjnano.8.191

• of applications. Epoxy systems combined with reinforcing fibers provide composites with high strength and stiffness, ease of molding complex shapes and environmental resistance at low densities. The properties of epoxy systems can be varied as a function of the molecular weight or the functionality

Stick–slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

• Iakov A. Lyashenko,
• Vadym N. Borysiuk and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2017, 8, 1889–1896, doi:10.3762/bjnano.8.189

• half-space characterized by an effective shear modulus [24] Assuming that the upper stamp has mass m, and the coordinate of the stamp center is X, let us consider the situation where the stamp is driven by a spring with the constant stiffness K. The free end of the spring moves with a constant velocity

• . An analogous dependence was described in [18], where the motion of a stamp with constant velocity was considered. Such configuration relates to the case where the spring, shown in Figure 1, is replaced by the rigid coupler. However, in real experiments, the spring (finite stiffness) between the stamp

Nanotribological behavior of deep cryogenically treated martensitic stainless steel

• Germán Prieto,
• Konstantinos D. Bakoglidis,
• Walter R. Tuckart and
• Esteban Broitman

Beilstein J. Nanotechnol. 2017, 8, 1760–1768, doi:10.3762/bjnano.8.177

• . According to [26], hardness (H) is defined as: where P is the maximum normal load and A is the contact area between the tip and the specimen. The contact area can be related to the contact stiffness by using Sneddon’s law [27]: Nanoindentation tests were performed using a Berkovich diamond tip, with an apex

• method utilizes the ratio between the hardness and the square of the elastic modulus (H/E2) as an independent characteristic parameter. The proposed method utilizes the maximum force applied during the test (P) and the calculated contact stiffness (S) from the nanoindentation data. S is defined as the

• control condition, and the force required to reach each depth was the same for both groups of specimens. Hence, the DCT samples must have a higher elastic limit [38][39]. The aforementioned phenomenon can be seen more clearly from the analysis of the contact stiffness, as DCT specimens showed

High-speed dynamic-mode atomic force microscopy imaging of polymers: an adaptive multiloop-mode approach

• Juan Ren and
• Qingze Zou

Beilstein J. Nanotechnol. 2017, 8, 1563–1570, doi:10.3762/bjnano.8.158

• sample, and a Celgard sample, differing in feature size and stiffness of two orders of magnitude, are imaged using the AMLM technique at high-speeds of 25 Hz and 20 Hz, respectively. The comparison of the images obtained to those obtained by using TM imaging at scan rates of 1 Hz and 2 Hz showed that the