Investigation of electron-induced cross-linking of self-assembled monolayers by scanning tunneling microscopy

• Patrick Stohmann,
• Sascha Koch,
• Yang Yang,
• Christopher David Kaiser,
• Julian Ehrens,
• Jürgen Schnack,
• Niklas Biere,
• Dario Anselmetti,
• Armin Gölzhäuser and
• Xianghui Zhang

Beilstein J. Nanotechnol. 2022, 13, 462–471, doi:10.3762/bjnano.13.39

• create ultrathin carbon nanomembranes (CNMs) [25][26]. Depending on the precursor molecules and the exposure conditions, thickness [27], mechanical stiffness [28], and electronic transport characteristics [29][30] of CNMs can be tailored. Carbon nanomembranes have been applied as electron microscopy

Effect of sample treatment on the elastic modulus of locust cuticle obtained by nanoindentation

• Chuchu Li,
• Stanislav N. Gorb and
• Hamed Rajabi

Beilstein J. Nanotechnol. 2022, 13, 404–410, doi:10.3762/bjnano.13.33

• ). The specimens were indented using a SA2 Nanoindenter (MTS Nano Instruments, Oak Ridge, TN, USA) equipped with a Berkovich diamond tip. The elastic modulus of the specimens was measured using the continuous stiffness measurement (CSM) technique. CSM is a well-established technique for obtaining the

• elastic modulus continuously as a function of the indentation depth (Figure 1d). The method involves applying a dynamic load on the top of the static load while loading. The dynamic unloading part is then used to measure the stiffness, which is further processed to calculate the elastic modulus of the

• period of time. Storing the specimens in water can also cause overhydration. The increased amount of water can result in swelling of specimens, which can consequently reduce the cuticle stiffness [9][15]. Here, we suggest a new protocol that can be used to measure the elastic modulus of cuticle specimens

Micro- and nanotechnology in biomedical engineering for cartilage tissue regeneration in osteoarthritis

• Zahra Nabizadeh,
• Mahmoud Nasrollahzadeh,
• Hamed Daemi,
• Mohamadreza Baghaban Eslaminejad,
• Ali Akbar Shabani,
• Mehdi Dadashpour,
• Majid Mirmohammadkhani and
• Davood Nasrabadi

Beilstein J. Nanotechnol. 2022, 13, 363–389, doi:10.3762/bjnano.13.31

• cues, and surface stiffness in osteochondral tissue differentiation and engineering is discussed with examples from recent studies that highlight their importance in tissue engineering applications. 2 Articular cartilage biology The composition and complex structure of articular cartilage need to be

Systematic studies into uniform synthetic protein nanoparticles

• Nahal Habibi,
• Ava Mauser,
• Jeffery E. Raymond and
• Joerg Lahann

Beilstein J. Nanotechnol. 2022, 13, 274–283, doi:10.3762/bjnano.13.22

• response at the cellular level. Several studies [28][29][30] have shown that considerations such as aspect ratio, stiffness/deformability, and particle surface roughness (deviation of circularity) can have a comparable impact on cellular uptake and/or endosomal escape. Hence, it is important to incorporate

Theoretical understanding of electronic and mechanical properties of 1T′ transition metal dichalcogenide crystals

• Seyedeh Alieh Kazemi,
• Sadegh Imani Yengejeh,
• Vei Wang,
• William Wen and
• Yun Wang

Beilstein J. Nanotechnol. 2022, 13, 160–171, doi:10.3762/bjnano.13.11

• and MoS2 structures display larger values. Since bulk and shear moduli are directly related to the mechanical stiffness of the materials, their Young’s moduli exhibit a similar trend as well. WS2 is the TMD most resistant to compression amongst all systems investigated, with B and Y values of 50 and

Nanoscale friction and wear of a polymer coated with graphene

• Robin Vacher and
• Astrid S. de Wijn

Beilstein J. Nanotechnol. 2022, 13, 63–73, doi:10.3762/bjnano.13.4

• the stiffness and r0 = 2.6 Å is the equilibrium bond length. The bending potential is approximated by an angular potential described in a table format. For graphene we use the AIREBO-M potential developed by O’Connor and co-workers [31]. It is an empirical many-body potential that is directly

Polarity in cuticular ridge development and insect attachment on leaf surfaces of Schismatoglottis calyptrata (Araceae)

• Venkata A. Surapaneni,
• Tobias Aust,
• Thomas Speck and
• Marc Thielen

Beilstein J. Nanotechnol. 2021, 12, 1326–1338, doi:10.3762/bjnano.12.98

• ][41][42]. Moreover, the amount of polysaccharide and cutin components present in the cuticle probably influences the stiffness and elastic behavior of the cuticle–cell wall interface [43] and certainly affects ridge formation. The thickened cuticle provides structural support to the growing epidermal

Cantilever signature of tip detachment during contact resonance AFM

• Devin Kalafut,
• Ryan Wagner,
• Maria Jose Cadena,
• Anil Bajaj and
• Arvind Raman

Beilstein J. Nanotechnol. 2021, 12, 1286–1296, doi:10.3762/bjnano.12.96

• thermal method [33] was then used to calculate the static cantilever bending stiffness. To study the process of tip detachment, we swept drive frequencies (low to high, then high to low) at selected drive amplitudes near the first contact resonance frequency of the cantilever–sample system. The cantilever

• step is pertinent not only to parameter identification, but also the dynamic simulations. Measurements of the resonance frequencies for both the free and contact cases allow us to identify critical stiffness quantities required for converting raw experimental output into physical quantities. The

• solution valid for both the first and second contact modes, thus determining kratio and γ for the system. We define the cantilever spring constant as [1]: and the first free vibrating mode stiffness as [40]: allowing us to solve for kcantilever and the flexural rigidity EI. Combining these with previous

Two dynamic modes to streamline challenging atomic force microscopy measurements

• Alexei G. Temiryazev,
• Andrey V. Krayev and
• Marina P. Temiryazeva

Beilstein J. Nanotechnol. 2021, 12, 1226–1236, doi:10.3762/bjnano.12.90

• classical contact mode, the friction force can be measured; when using off-resonance dynamic modes, stiffness and adhesion in the samples can be determined. Obviously, in determining the mechanical properties, the force of tip–surface interaction should be somewhat greater than that required if the task is

Open-loop amplitude-modulation Kelvin probe force microscopy operated in single-pass PeakForce tapping mode

• Gheorghe Stan and
• Pradeep Namboodiri

Beilstein J. Nanotechnol. 2021, 12, 1115–1126, doi:10.3762/bjnano.12.83

• oscillations is shown in Figure 2. The raw PFT signal (gray curve in Figure 2) is especially noisy right after each detachment of the AFM probe from contact due to the relative compliance of the probe used, with a nominal stiffness of 3.0 N/m and first resonance frequency of 67 kHz. This extra high-frequency

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

• topography, for example, adhesion, phase shift, stiffness, work function, or friction. In the following section, the utility of CNN in SPM is illustrated through several examples taken from the literature. Enhancing speed of image acquisition As discussed above, SPM imaging is inherently slow. One of the

• quantities, that is, frequency (giving the stiffness), amplitude (giving the piezoresponse), Q (dissipation), and phase (directionality of polarization). PFM can map piezoelectric domains and the inverse piezoresponse of a sample, but signals are notoriously low. In this work, two arrays (real and imaginary

• blind reconstruction [136]. A common means to distinguish between healthy and sick cells is the elastic modulus, determined by measuring the stiffness with AFM force–distance curves and then fitting to a model. Several works have applied machine learning to analysis of the force curves. The data here is

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

• Sepand Tehrani Fateh,
• Lida Moradi,
• Elmira Kohan,
• Michael R. Hamblin and
• Amin Shiralizadeh Dezfuli

Beilstein J. Nanotechnol. 2021, 12, 808–862, doi:10.3762/bjnano.12.64

• ) gas-filled structures that are stabilized by a lipid, surfactant, protein, or polymer shell, whose stiffness or rigidity can affect the final outcome of the MBs upon exposure to US [71][72][73]. During the cavitation event, backscattered energy leads to the expanding and shrinking of the MBs, which

Reducing molecular simulation time for AFM images based on super-resolution methods

• Zhipeng Dou,
• Jianqiang Qian,
• Yingzi Li,
• Rui Lin,
• Jianhai Wang,
• Peng Cheng and
• Zeyu Xu

Beilstein J. Nanotechnol. 2021, 12, 775–785, doi:10.3762/bjnano.12.61

• virtual atom is added above the tip apex and they are connected with a spring in the z-direction. The virtual atom is excited by a sinusoidal signal, mimicking the acoustic excitation of AM-AFM. The excited frequency is adjusted by the spring stiffness. A damping force is applied on the tip to ensure the

Physical constraints lead to parallel evolution of micro- and nanostructures of animal adhesive pads: a review

• Thies H. Büscher and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2021, 12, 725–743, doi:10.3762/bjnano.12.57

• influence of different factors, such as substrate roughness and pad stiffness, on contact forces, and review the chemical composition of pad fluids, which is an important component of an adhesive function. Attachment systems are omnipresent in animals. We show parallel evolution of attachment structures on

• contact with a wide range of microscopically rough substrate profiles (Figure 2). Also, due to the low bending stiffness of their terminal plates, can even adapt to substrates with roughness on a sub-nanometre scale [1][3][4][34]. Smooth pads can also maximise their contact areas with a variety of

• spatula, terminating tips of the cuticle outgrowths in hairy systems form the superficial film. These films are responsible for proper contact formation with the substrate due to their low bending stiffness at a minimum load [239]. The film/spatula is able to adapt to the surface profile and to replicate

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• the contact potential difference measured by Kelvin probe force microscopy. Using 3D force profiles of the same area we determine the relative stiffness of the Moiré region allowing us to analyse both electronic and mechanical properties of the 2D layer simultaneously. We obtain a sheet stiffness of

• -BN/Cu(111) substrate. Keywords: decoupling layers; hexagonal boron nitride; local stiffness; Moiré superstructure; work function variation; Introduction Two-dimensional hexagonal boron nitride (h-BN) is among the list of materials that garnered tremendous interest following the exfoliation of mono

• - and few-layer thick graphene films [1][2]. Unique properties, such as high thermal stability and conductivity, immense intra-sheet stiffness, and excellent dielectric properties, make h-BN interesting for technological applications. For example, thin films of h-BN have been used as a passivating layer

Determining amplitude and tilt of a lateral force microscopy sensor

• Oliver Gretz,
• Alfred J. Weymouth,
• Thomas Holzmann,
• Korbinian Pürckhauer and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2021, 12, 517–524, doi:10.3762/bjnano.12.42

• in Figure 1b [8]. In our group, we have used this method to quantify molecular stiffness at low temperature [9] and to evaluate the potential energy landscape above a molecule at room temperature [10]. More recently, we used LFM with a CO-terminated tip to investigate the internal structure of a

• related to the sensor parameters and the weighted average of the force gradient over the tip oscillation, ⟨kts⟩(x0, z0), where x0 and z0 define the average tip position over one oscillation cycle [14]: Here, f0 is the resonance frequency of the sensor away from the surface and k is the stiffness of the

Exploring the fabrication and transfer mechanism of metallic nanostructures on carbon nanomembranes via focused electron beam induced processing

• Christian Preischl,
• Linh Hoang Le,
• Elif Bilgilisoy,
• Armin Gölzhäuser and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2021, 12, 319–329, doi:10.3762/bjnano.12.26

• arbitrary substrates or grids to obtain free-standing 2D membranes [25]. The specific choice of the self-assembling molecules determines the thickness, porosity, stiffness, and the mechanical/electrical properties of the resulting CNM [26][27]. The SAMs that are used for the fabrication of CNMs consist of

The nanomorphology of cell surfaces of adhered osteoblasts

• Christian Voelkner,
• Mirco Wendt,
• Regina Lange,
• Max Ulbrich,
• Martina Gruening,
• Susanne Staehlke,
• Barbara Nebe,
• Ingo Barke and
• Sylvia Speller

Beilstein J. Nanotechnol. 2021, 12, 242–256, doi:10.3762/bjnano.12.20

• stiffness of the ruffle structure, even when a harder (fixed) protein content is present. Note that for living cells such contrast is absent as can be seen in Figure 3c and Figure 3d. Figure 4a shows an example of a peripheral ruffle. Peripheral ruffles sometimes are attributed to loosened lamellipodia

Determination of elastic moduli of elastic–plastic microspherical materials using nanoindentation simulation without mechanical polishing

• Hongzhou Li and
• Jialian Chen

Beilstein J. Nanotechnol. 2021, 12, 213–221, doi:10.3762/bjnano.12.17

• the maximum displacement hmax (the maximum displacement of the indenter relative to the initial undeformed surface), and the third is the unloading stiffness. The initial unloading stiffness is used to extract the elastic modulus of the specimen via the well-known Oliver–Pharr method [3][4]. Cheng and

• that the shear modulus is equal to E/[2(1 + ν)], differentiating P with respect to h leads to where S = dP/dh is the initial stiffness of the unloading curve, defined as the slope of the upper portion of the unloading curve during the initial stages of unloading (also called contact stiffness), and E

• . Knowing the contact depth and the shape of the indenter, determined through the “area function”, the contact area is then determined. If contact stiffness and contact area are known, Equation 3 and Equation 4 can be used to determine the elastic modulus of a material. Effects of non-rigid indenters on the

Numerical analysis of vibration modes of a qPlus sensor with a long tip

• Kebei Chen,
• Zhenghui Liu,
• Yuchen Xie,
• Chunyu Zhang,
• Gengzhao Xu,
• Wentao Song and
• Ke Xu

Beilstein J. Nanotechnol. 2021, 12, 82–92, doi:10.3762/bjnano.12.7

• contributes to Δf. If φ < 45°, the lateral force gradient has a greater impact. For most cases, it is desirable to detect a larger vertical force gradient signal, so we need Ax/Az < 1. The in-phase modes were found to fulfil this requirement. Thirdly, we want the stiffness of the qPlus sensor to be large

• enough to allow for a stable small-amplitude operation [1]. The equivalent stiffness keq of the qPlus sensor is shown in Figure 8, which is calculated from the strain energy and the tip amplitude with an equivalent point-mass model [28]. We see in Figure 8c that for a 0.075 mm tip, there is an optimal

• slightly higher than that measured in atmosphere due to less air damping. Equivalent stiffness keq of the qPlus sensor as a function of the tip length depicted for the four different tip diameters. Q factor as a function of the tip length depicted for the four different tip diameters. Material parameters

Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

• Dorothee Silbernagl,
• Media Ghasem Zadeh Khorasani,
• Natalia Cano Murillo,
• Anna Maria Elert and
• Heinz Sturm

Beilstein J. Nanotechnol. 2021, 12, 58–71, doi:10.3762/bjnano.12.5

• of atomic force microscopy (AFM) is the measurement of physical properties at sub-micrometer resolution. Methods such as force–distance curves (FDCs) or dynamic variants (such as intermodulation AFM (ImAFM)) are able to measure mechanical properties (such as the local stiffness, kr) of nanoscopic

• described by yielding a dimensionless relative spring constant (or stiffness) kr, with kr ≤ 1. A detailed derivation of kr and a discussion regarding this parameter can be found in Supporting Information File 1. For a sample that is not measurably deformed by the applied force (k >> kc), kr ≈ 1. This is the

• case when the sample is stiffer than the experimental setup, which marks the limitation of the method. Compliant or soft samples yield a stiffness value kr < 1; the lower the value the softer/more compliant the sample. The evaluation of this parameter is shown in Figure 2b, again for averaged example

Nanomechanics of few-layer materials: do individual layers slide upon folding?

• Ronaldo J. C. Batista,
• Rafael F. Dias,
• Ana P. M. Barboza,
• Alan B. de Oliveira,
• Taise M. Manhabosco,
• Thiago R. Gomes-Silva,
• Matheus J. S. Matos,
• Andreij C. Gadelha,
• Cassiano Rabelo,
• Luiz G. L. Cançado,
• Ado Jorio,
• Hélio Chacham and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2020, 11, 1801–1808, doi:10.3762/bjnano.11.162

• mechanical properties of folded edges, which allows for the experimental determination of the bending stiffness (κ) of multilayered 2D materials as a function of the number of layers (n). In the case of talc, we obtain κ ∝ n3 for n ≥ 5, indicating no interlayer sliding upon folding, at least in this

• all those cases, the interlayer adhesion energy (α), the substrate adhesion energy (αs), and the bending stiffness (κ) govern folding, sliding, and wrinkling of 2D materials, which are ultimately responsible for those unusual kinds of behavior. α is intimately related to tribological properties of

• of the folds in the suspended graphene [17]. After the successful synthesis of graphene in 2004 [1], many other 2D materials have been produced [12][18][19][20][21][22][23]. The investigation of their bending stiffness as a function of thickness, interlayer adhesion energy, and adhesion energy on

Application of contact-resonance AFM methods to polymer samples

• Sebastian Friedrich and
• Brunero Cappella

Beilstein J. Nanotechnol. 2020, 11, 1714–1727, doi:10.3762/bjnano.11.154

• underlying physical phenomena and of factors influencing the measurements. A commonly used method to analyze CR data requires the determination of the relative position of the tip, the calculation of the normalized contact stiffness, and the use of a calibration sample for the calculation of the elastic

• stiffness prompts an increase of the contact-resonance frequency (CR frequency). The CR frequency can be obtained from single-point measurements or tracked during scanning with techniques such as dual AC resonance tracking (DART) [6][7]. The vibrational motion of the cantilever is usually described using

• interactions. Such models allow one to calculate the contact stiffness from the measured CR frequency. Then, from the contact stiffness, the elastic modulus of the sample can be determined. This technique has been successfully applied on rather stiff materials such as silicon [11] or chalcogenide glasses [12

Design of V-shaped cantilevers for enhanced multifrequency AFM measurements

• Mehrnoosh Damircheli and
• Babak Eslami

Beilstein J. Nanotechnol. 2020, 11, 1525–1541, doi:10.3762/bjnano.11.135

• dynamics of the cantilever more accurately. Wang et al. have used the finite element method (FEM) as an alternative approach to obtain the stiffness and the natural frequencies of for both rectangular and V-shaped cantilevers [9]. Additionally, other studies were done by Cleveland et al. [10] to measure

• the stiffness of AFM cantilevers. Later on, Sader et al. developed a nondestructive method for the evaluation of the spring constant, which relies solely on the determination of the unloaded resonant frequency of the cantilever [11]. This work was in contrast to the method of Cleveland et al., which

• stiffness and high lateral stiffness. Therefore, they can apply low forces to soft matter in normal mode while having a stable lateral mode. Additionally, their high lateral stiffness is advantageous in nanomanipulation applications moving particles over surfaces [12]. Morris stated in his book that

Protruding hydrogen atoms as markers for the molecular orientation of a metallocene

• Linda Laflör,
• Michael Reichling and
• Philipp Rahe

Beilstein J. Nanotechnol. 2020, 11, 1432–1438, doi:10.3762/bjnano.11.127

• atoms were used as probe particles and frequency-shift Δf data were calculated for an oscillation amplitude of 0.5 nm. Lateral and vertical stiffness were chosen as 0.5 and 20 N/m, respectively. FDCA molecular models in the DFT-optimised geometries (using geo 1 and geo 2 from [22], see Figure 1a,b) were

• shown in Figure 2o,p. We use Lennard-Jones parameters for CO and Xe tips, a neutral probe particle, and stiffness values of (kx, ky, kz) = (0.5, 0.5, 20) N/m, yielding the results for CO reproduced in Figure 2f–i and for Xe in Figure 2k–n at the same heights. Both series of images exhibit a remarkable