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

• tangential component of adhesion force [70], often poses difficulties in returning the NEM switch to its off position. Inducing resonant oscillations in the NEM switching element in the on position was found to be an effective solution for its release from the contact. The resonant oscillation modes induced

• the mechanical contact determines the adhesion force (Fadh) value which is responsible for keeping the contacting surfaces together. Fundamentally, the contact is formed by atoms interacting across the contact interface. At the nanoscale, many models of nanocontact behaviour are based on a single

• -asperity model, where contacting elements are represented by single asperities with curvature radii from tens of nanometres to micrometres and are assumed to be ideally smooth [72]. According to adhesion theories [73][74][75][76], the adhesion force can be evaluated as Fadh ≈ R·Δγ, where R is radius of

Dry adhesives from carbon nanofibers grown in an open ethanol flame

• Christian Lutz,
• Julia Syurik,
• C. N. Shyam Kumar,
• Christian Kübel,
• Michael Bruns and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 2719–2728, doi:10.3762/bjnano.8.271

• fabricated arrays of carbon nanofibers with different degrees of orientation. Inspired by the dry adhesive system of geckos we investigated the adhesive properties of such carbon nanofiber arrays with ordered and random orientation. AFM-based force spectroscopy revealed that adhesion force and energy rise

• photoelectron peaks of metallic Cu, Ag, and Au. Sample cleaning to remove organic contaminations was performed with the Thermo Scientific MAGCIS (Mono Atomic and Gas Cluster Ion Source) using Ar1000+ clusters at 8 keV primary energy and a raster size of 2 × 4 mm2. The adhesion force and energy were determined

• with the adhesion of randomly oriented CNFs and oriented CNFs in Figure 6. The two curves in the diagrams represent trace (dashed blue line) and retrace (solid red line). The preload force was always set to 2 μN. The adhesion force is defined as the force that is necessary to lift the sphere glued to

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

• and Figure 6 was obtained by doing wear measurements at different locations on the sample. Scanning electronic microscopy images of the probes after wear showed that no significant wear of the AFM tip occurred after the set of experiments. Such facts were also confirmed by the adhesion force

Patterning of supported gold monolayers via chemical lift-off lithography

• Liane S. Slaughter,
• Kevin M. Cheung,
• Sami Kaappa,
• Huan H. Cao,
• Qing Yang,
• Thomas D. Young,
• Andrew C. Serino,
• Sami Malola,
• Jana M. Olson,
• Stephan Link,
• Hannu Häkkinen,
• Anne M. Andrews and
• Paul S. Weiss

Beilstein J. Nanotechnol. 2017, 8, 2648–2661, doi:10.3762/bjnano.8.265

• height maps in Figure 3 to the presence of Au–alkanethiolate compounds in all regions of the patterned PDMS. In addition to topographic height measurements, we used PF-AFM to determine the adhesion force (i.e., the force needed to pull an AFM tip off a surface) to investigate chemical contrast on

Material property analytical relations for the case of an AFM probe tapping a viscoelastic surface containing multiple characteristic times

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2230–2244, doi:10.3762/bjnano.8.223

• the portion due to adhesion. The adhesion force is constant during contact, and translates in our analytical equation into a simple offset. Although the adhesion force in Figure 3b does not emerge as a sudden step, but rather builds up gradually according to the vdW attractive interaction, the sudden

• . As a final comment on the dissipated energy, we point out that both simulations and analytics assume that dissipation stems exclusively from viscoelastic dissipation and the adhesion force [41][42]. This neglects other sources, such as capillary forces [41], rate dependent adhesion forces, and long

• contact, a constant adhesion force was added as as already explained. The calculation of the tapping amplitude (A) for the construction of the dissipative and virial spectroscopy curves (Figure 4) was performed by extracting the Fourier components of the tip deflection (z(t)) that are related to the

Evaluation of preparation methods for suspended nano-objects on substrates for dimensional measurements by atomic force microscopy

• Petra Fiala,
• Daniel Göhler,
• Benno Wessely,
• Michael Stintz,
• Giovanni Mattia Lazzerini and
• Andrew Yacoot

Beilstein J. Nanotechnol. 2017, 8, 1774–1785, doi:10.3762/bjnano.8.179

• properties (e.g., surface potential of material and substrate, tendency of nano-objects to agglomerate, adhesion force, size and shape). Therefore several preparation methods (membrane filtration, drying, rinsing, dip coating, electrostatic precipitation, thermal precipitation) on silicon (Si) and with

Measuring adhesion on rough surfaces using atomic force microscopy with a liquid probe

• Juan V. Escobar,
• Cristina Garza and
• Rolando Castillo

Beilstein J. Nanotechnol. 2017, 8, 813–825, doi:10.3762/bjnano.8.84

• ], in self-cleaning – because liquid-repellency is correlated with a low adhesion force –, drag reduction [14], fog harvesting [15], and to understand adhesive interactions between imaging materials, which are crucial in print-engine design, and print-process development in the printing industry [16

• adhesion force: 1) An array of silicon structures with nanometer-scale peaks (test grating TGT1 from NT-MDT Co., Russia; Figure 1) normally used for determining the radius of curvature of the AFM tip. A macroscopic mercury drop wets this surface following the Cassie–Baxter model [13] (θc ≈ 150°). The

• tips: As mentioned in the introduction, we first measure the adhesion force between standard Si3N4 tips in contact with freshly cleaved mica to validate our general method. The radius of these tips was obtained using the tip–shape deconvolution method [28][29] on a test grating (TGT1 from NDT-MDT Co

Structural and tribometric characterization of biomimetically inspired synthetic "insect adhesives"

• Matthias W. Speidel,
• Malte Kleemeier,
• Andreas Hartwig,
• Klaus Rischka,
• Angelika Ellermann,
• Rolf Daniels and
• Oliver Betz

Beilstein J. Nanotechnol. 2017, 8, 45–63, doi:10.3762/bjnano.8.6

• adhesion than the second (Mann–Whitney-U test; p < 0.001; N = 12), i.e., more than twice as high an adhesion force (Figure 3; Supporting Information File 1, Table S2). Within the first generation, the adhesion of all emulsions, except VG50 and VP50, did not significantly differ from each other (Figure 3a

• ; Supporting Information File 1, Table S3). However, emulsion VP50 exhibited the clear tendency of having the highest adhesion force, whereas emulsion VG50 showed the lowest adhesion force (Supporting Information File 1, Table S2). Moreover, all four emulsions revealed significantly higher adhesion compared

•  3b; Supporting Information File 1, Tables S2 and S4). The remaining emulsions SA2, OA2, SW2 and OW2 and the controls water and squalane revealed no significant differences between one another (Figure 3b; Supporting Information File 1, Table S4). The adhesion force of these emulsions and water was

“Sticky invasion” – the physical properties of Plantago lanceolata L. seed mucilage

• Agnieszka Kreitschitz,
• Alexander Kovalev and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2016, 7, 1918–1927, doi:10.3762/bjnano.7.183

• ) and video camera KODAK Motion Corder Analyzer Series SR (Eastman Kodak Co., San Diego, CA, USA) was used. The measurements were done on hydrated seeds (with developed mucilage envelope) and were performed until the adhesion force was no longer detectable. Images of the mucilage contact area were taken

• determined from the built-in alidade and then used for calculating the static friction coefficient. The friction coefficient and adhesion force were both calculated from the measured results as described in [32]. Shortly, the critical angle, φc, at which the glass block started sliding corresponds to the

• following equation: where µ is the friction coefficient, Fad is the adhesion force, Fgb = mgb·g, mgb is the mass of the glass block, and g = 9.813 m/s2 is the gravitational acceleration. At the same time, a special normalization procedure was carried out within each measurement set to obtain a smooth time

Atomic force microscopy as analytical tool to study physico-mechanical properties of intestinal cells

• Christa Schimpel,
• Oliver Werzer,
• Eleonore Fröhlich,
• Gerd Leitinger,
• Markus Absenger-Novak,
• Birgit Teubl,
• Andreas Zimmer and
• Eva Roblegg

Beilstein J. Nanotechnol. 2015, 6, 1457–1466, doi:10.3762/bjnano.6.151

• the cantilever got in contact with the sample. Due to strong adhesion forces (van der Waals forces), the tip snapped in contact with the cell membrane. When retracting the tip, adhesion was maintained until the cantilever-force overcame the pull-off force (also referred as adhesion force) [51]. Lowest

Capillary and van der Waals interactions on CaF₂ crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

• Annalisa Calò,
• Oriol Vidal Robles,
• Sergio Santos and
• Albert Verdaguer

Beilstein J. Nanotechnol. 2015, 6, 809–819, doi:10.3762/bjnano.6.84

• of some nanometers above the surface [14]. In Equation 11 it has been assumed that when the capillary forms the force is constant and equal to the adhesion force (FAD) (see Experimental section). In this work, Equation 10 and 11 have been employed to reconstruct force curves according to the Sader

• , are shown which are taken in the same region of a dry CaF2 crystal. The strong adhesion force (FAD ≈ 10 nN) depends on tip radius (R ≈ 40 nm in this case, see Supporting Information File 1, Figure S2). Curves were aligned and averaged before fitting in order to minimize noise in the region of interest

• rupture of a capillary bridge. This can be inferred from the high hysteresis in the retracting portion of the static force curves, which spans an average distance of about 30 nm and exhibits an adhesion force of almost 6 nN compared to the approach path. But it is only from dynamic AFM experiments that

Applications of three-dimensional carbon nanotube networks

• Manuela Scarselli,
• Paola Castrucci,
• Francesco De Nicola,
• Ilaria Cacciotti,
• Francesca Nanni,
• Emanuela Gatto,
• Mariano Venanzi and
• Maurizio De Crescenzi

Beilstein J. Nanotechnol. 2015, 6, 792–798, doi:10.3762/bjnano.6.82

• in contact with water from the equation [19]: where γLV denotes the surface tension of the liquid–vapor (LV) interface for water γLV = 72.5 mN/m, and Θ is the measured contact angle (Θ = 175°). The estimated adhesion force of the water droplet (20 µL) reported in Figure 4b, is about 50 µN. Measuring

Dynamic force microscopy simulator (dForce): A tool for planning and understanding tapping and bimodal AFM experiments

• Horacio V. Guzman,
• Pablo D. Garcia and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2015, 6, 369–379, doi:10.3762/bjnano.6.36

• stiff and small contacts with low adhesion forces. The DMT model [47] considers an elastic term given by Hertz contact mechanics as and an adhesion force that acts outside the contact area given by where γ is the sample surface energy. Johnson–Kendall–Roberts contact mechanics (JKR) The JKR model is

Increasing throughput of AFM-based single cell adhesion measurements through multisubstrate surfaces

• Miao Yu,
• Nico Strohmeyer,
• Jinghe Wang,
• Daniel J. Müller and
• Jonne Helenius

Beilstein J. Nanotechnol. 2015, 6, 157–166, doi:10.3762/bjnano.6.15

• retraction the upward acting force on the cell increases until the force needed to initiate cell de-adhesion is reached, thereafter, unbinding events occur (Figure 1C). The maximum force is called the adhesion force and is a measure of how strong the cell adhered to the substrate. Unbinding events correlate

• limitations in optical microscopy, they are usable for standard microscopy mostly used in combination with SCFS. If the PDMS masks interfere with optical microscopy, the masks with glass surfaces are recommended. Comparison of the non-specific adhesion force on glass and PDMS surfaces In our experience, non

• -dependent adhesion to extracellular matrix proteins To demonstrate that PDMS masks are a useful tool to increase throughput and comparability of results on different ECM proteins in SCFS, we conducted a small adhesion-force screening with four cell lines and three different ECM proteins. Thereto, we coated

The capillary adhesion technique: a versatile method for determining the liquid adhesion force and sample stiffness

• Daniel Gandyra,
• Stefan Walheim,
• Stanislav Gorb,
• Wilhelm Barthlott and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2015, 6, 11–18, doi:10.3762/bjnano.6.2

• adhesion force of a small structure or structural unit (e.g., an individual filament, hair, micromechanical component or microsensor) to a liquid and its elastic properties. The method involves the creation and development of a liquid meniscus upon touching a liquid surface with the structure, and the

• subsequent disruption of this liquid meniscus upon removal. The evaluation of the meniscus shape immediately before snap-off of the meniscus allows the quantitative determination of the liquid adhesion force. Concurrently, by measuring and evaluating the deformation of the structure under investigation, its

• ) determination of the water adhesion force and the elasticity of individual hairs (trichomes) of the floating fern Salvinia molesta. (2) The investigation of human head hairs both with and without functional surface coatings (a topic of high relevance in the field of hair cosmetics) was performed. The method

Modification of a single-molecule AFM probe with highly defined surface functionality

• Fei Long,
• Bin Cao,
• Ashok Khanal,
• Shiyue Fang and
• Reza Shahbazian-Yassar

Beilstein J. Nanotechnol. 2014, 5, 2122–2128, doi:10.3762/bjnano.5.221

• a monolayer of amino-terminated poly(ethylene glycol) (PEG) was prepared. PEG was used to reduce the background adhesion force, and as a spacer to better discriminate between specific and non-specific interactions in the force curves [20]. The functionalized probes after ‘click’ modification were

• our method can successfully attach carboxylic acid groups to the probe through the ‘click’ reaction. To further quantify the carboxylic acid groups on a probe, the widely used Poisson statistical method was employed [23][24]. This method assumes the adhesion force is composed of specific interactions

• , such as hydrogen bonds, and non-specific interactions, such as van der Waals forces, where Fav is the total average adhesion force, nav is the average number of specific interactions, which is hydrogen bonding in our case, Fi is the magnitude of the specific interaction, and F0 is non-specific

Hydrophobic interaction governs unspecific adhesion of staphylococci: a single cell force spectroscopy study

• Nicolas Thewes,
• Peter Loskill,
• Philipp Jung,
• Henrik Peisker,
• Markus Bischoff,
• Mathias Herrmann and
• Karin Jacobs

Beilstein J. Nanotechnol. 2014, 5, 1501–1512, doi:10.3762/bjnano.5.163

• adhesion force values. The outcome usually results from multiple parallel processes, such as adsorption, desorption, and adhesion. Moreover, results obtained from flow chamber experiments depend on the exact flow conditions of the used chamber [15]. In the last decade, a more quantitative method for

• relative to the point of zero force [24]. From the retraction curve, the adhesion force is taken as the depth of the global minimum [24]. Since in some cases, the overall adhesion force decreased after more than about 150 force/distance curves (possibly due to stress applied by the large number of adhesion

• ) velocity was varied between 400 nm/s and 2400 nm/s, yet no significant influence on the adhesion force was recorded (Figure 5A). By varying the tip velocity, we implicitly varied the time the bacterium is enabled to gain contact to the surface. Within the range probed, the contact time (estimated to be of

Model systems for studying cell adhesion and biomimetic actin networks

• Dorothea Brüggemann,
• Johannes P. Frohnmayer and
• Joachim P. Spatz

Beilstein J. Nanotechnol. 2014, 5, 1193–1202, doi:10.3762/bjnano.5.131

• observation was not as predicted by the switchblade model and is more consistent with the deadbolt model. Goennenwein et al. reconstituted integrin αIIbβ3 into supported lipid bilayers to measure their adhesion force against RGD-peptide carrying giant vesicles. With this setup a simple and powerful tool was

Hairy suckers: the surface microstructure and its possible functional significance in the Octopus vulgaris sucker

• Francesca Tramacere,
• Esther Appel,
• Barbara Mazzolai and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2014, 5, 561–565, doi:10.3762/bjnano.5.66

• rough surfaces generating a pressure difference of up to 0.268 MPa [11]. To obtain such an adhesion force, a perfect seal at the interface between the sucker and the substrate is crucial. Similar to abalone, in which the external surface of its side foot is characterised by many crests and grooves, in

• refer to grey arrow in Figure 1g). Based on our recent results, an adhesion force (please refer to black arrows in Figure 1f), exerted by the dense network of hairs, is present on the surface of the acetabular protuberance. This force might work in addition to the cohesive forces of water, assisting in

• keeping the orifice closed for extended periods of time and significantly increasing the resistance to the restoring force. In this new scenario, the restoring elastic force is balanced by the cohesive forces of the water in the infundibular compartment and the adhesion force exerted by the hairs. In this

Exploring the complex mechanical properties of xanthan scaffolds by AFM-based force spectroscopy

• Hao Liang,
• Guanghong Zeng,
• Yinli Li,
• Shuai Zhang,
• Huiling Zhao,
• Lijun Guo,
• Bo Liu and
• Mingdong Dong

Beilstein J. Nanotechnol. 2014, 5, 365–373, doi:10.3762/bjnano.5.42

• the AFM tip. The tiny mechanical response is due to the adhesion force between the overlapping fibrils. As a more complex example, the inset of Figure 7B illustrates the case in which the tip fished two fibrils, one of which detached from a third underlying fibril before the two fibrils ruptured from

Exploring the retention properties of CaF₂ nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid

• Matthias Wasem,
• Joachim Köser,
• Sylvia Hess,
• Enrico Gnecco and
• Ernst Meyer

Beilstein J. Nanotechnol. 2014, 5, 36–43, doi:10.3762/bjnano.5.4

• explained in terms of less contacting asperities in the substrate–particles interface and hence less adhesion force acting between them. Our experiments show the exact opposite behavior, at a higher substrate roughness we observe a higher retention of the nanoparticles. We explain this in terms of the

AFM as an analysis tool for high-capacity sulfur cathodes for Li–S batteries

• Renate Hiesgen,
• Seniz Sörgel,
• Rémi Costa,
• Linus Carlé,
• Ines Galm,
• Natalia Cañas,
• Brigitta Pascucci and
• K. Andreas Friedrich

Beilstein J. Nanotechnol. 2013, 4, 611–624, doi:10.3762/bjnano.4.68

• significant differences were found for the deformation values with the exception of cellulose as a binder material. The adhesion force was smallest for the fluorine containing PVDF binder. For the identification of sulfur the stiffness values were used. During the stiffness measurements the tip puts a

• images measure 3 μm × 3 μm. The topography is displayed together with the simultaneously measured mapping of deformation, adhesion force, DMT modulus (stiffness), TUNA™ current, and peak current. The different properties of image areas allowed for a distinction of different surface materials, which is

• a lower deformation. The adhesion force is higher at those parts of the surface where the stiffness values are smaller. In the centre of the TUNA current image in Figure 6, the current density has lower intensities, whereas the corresponding stiffness is especially high. Deformation values, on the

Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

• the top of the CNT. In the second case, the particle remains attached to the substrate. The common explanation for this difference is based on the adhesion force between the catalyst and the substrate. It is reported that a strong (weak) interaction furthers the base (tip) related mode. However

Effect of normal load and roughness on the nanoscale friction coefficient in the elastic and plastic contact regime

• Aditya Kumar,
• Thorsten Staedler and
• Xin Jiang

Beilstein J. Nanotechnol. 2013, 4, 66–71, doi:10.3762/bjnano.4.7

• elimination of any nonzero measured friction force that may be present at a normal load of zero, see Figure 2. This is usually explained by an additional load term due to an intrinsic adhesive force and/or artifacts generated by the equipment. The adhesion force term itself consists of various attractive

Characterization of the mechanical properties of qPlus sensors

• Jan Berger,
• Martin Švec,
• Martin Müller,
• Martin Ledinský,
• Antonín Fejfar,
• Pavel Jelínek and
• Zsolt Majzik

Beilstein J. Nanotechnol. 2013, 4, 1–9, doi:10.3762/bjnano.4.1

• , experiments showed that the adhesion force between tuning fork and glue was strong enough to hold the tungsten wire during the measurement. On the other hand, the surface of the tuning fork is smooth. Therefore the glue can be easily removed after measuring, without damaging the sensor and voiding its