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

• of samples (Nat. Commun. 2014, 5, 3126). This method gives evidence for the linearity of the relation between the frequency shift of the cantilever first flexural mode Δf1 and the square of the frequency shift of the second flexural mode Δf22. In the present work, we showed that a similar linear

• , pressure or humidity. Since its invention, the atomic force microscope (AFM) [4] has confirmed its value for locally determining nanomechanical properties, such as the Young’s modulus, of the sample surface. Initially, the measures were done qualitatively, with the cantilever operated in intermittent

• on the equations established by Rabe [9] and Rabe et al. [10] for atomic force acoustic microscopy (AFAM) [11][12][13][14]. They describe the dynamics of a clamped cantilever elastically coupled with the sample surface at its tip end. These equations have the disadvantage of strongly depending on 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

• materials and to estimate the mixture ratio of the constituent components in nanocomposites. The major influencing factors, namely amplitude feedback set-point, drive frequency and laser spot position along the cantilever beam, were systematically investigated. Employing different set-points induces

• alternation of tip–sample interaction forces and thus different harmonic responses. The numerical simulations of the cantilever dynamics were well-correlated with the experimental observations. Owing to the deviation of the drive frequency from the fundamental resonance, harmonic amplitude contrast reversal

• interpretation of tapping phase results is rather complex because many factors may influence the results [14][15]. For force modulation and contact resonance operations, the tip is maintained in contact with the sample during the scan while the cantilever oscillations are monitored. The amplitude in force

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

• from force–distance curves measured with an AFM (Dimension Icon, Bruker). In order to have a defined contact, a 20 μm SiO2 sphere was glued to the end of a tipless silicon cantilever (All In One-TL from BudgetSensors) using the approach of Mak and co-workers [33]. We confirmed by SEM that no glue was

• left on the top of the SiO2 sphere (see the insert in Figure 7 below). For the adhesion measurements a constant ramp rate of 1.5 μm/s was applied (adhesion measurement with ramp rates between 0.2 and 8 μm/s showed similar results). The spring constant of the cantilever was determined to 7.74 N/m with

• the thermal tune method [34] integrated in the AFM software. All the measurements presented here were conducted with the same cantilever. Results and Discussion Growth of carbon nanofibers Inspired by the study of Zhang and Pan [9], we aligned the sample, the magnet and the shield parallel to the

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

• lateral force microscopy (LFM) signal proportional to the friction force) of the cantilever stemming from the circular displacement of the contact features a sinusoidal signal with the same frequency as the relative circular displacement of the contact. Then a lock-in amplifier is used to register the

• real-time amplitude of the LFM signal of the cantilever (or friction force) during the wear experiment in order to determine prospective variations of the friction properties during the experiment. For example, this option may be advantageously implemented for investigating the correlation between

• 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

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

• -force set-point between 200 and 400 pN was maintained, except where otherwise indicated. These conditions enabled sufficient contact between tips and samples for imaging, while minimizing the load from the cantilever applied to the PDMS. Scanning electron microscopy of Au-on-Si masters Scanning electron

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

• studied, as shown in Figure 12c and Figure 12d. One can see that the cantilever tip radius causes an overestimation of the NB/ND width and contact angle. The width error introduced by the applied tip radius is about 3%, while the contact angle error is near 0.4%. Conclusion Current automated NB/ND

Interface conditions of roughness-induced superoleophilic and superoleophobic surfaces immersed in hexadecane and ethylene glycol

• Yifan Li,
• Yunlu Pan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2017, 8, 2504–2514, doi:10.3762/bjnano.8.250

• AFM technique was used for the measurement of boundary slip, as shown in Figure 3. A borosilicate sphere (GL018B/45-33, MO-Sci Corporation) with a measured diameter of about 56.5 μm was glued to the end of a rectangular cantilever of an AFM tip (ORC8, Bruker) by using epoxy resin to prepare the

• characterizes the degree of boundary slip at the solid–liquid interface, and can be obtained by the hydrodynamic force on the cantilever detected with CCD. Schematic illustrating possible definitions of the boundary-slip condition at a rough surface. (a) The boundary-slip condition with the reference surface

Fabrication of gold-coated PDMS surfaces with arrayed triangular micro/nanopyramids for use as SERS substrates

• Jingran Zhang,
• Yongda Yan,
• Peng Miao and
• Jianxiong Cai

Beilstein J. Nanotechnol. 2017, 8, 2271–2282, doi:10.3762/bjnano.8.227

• machined micro/nanostructures. The scan size was 50 × 50 μm2. The elastic constant of the silicon cantilever was 0.2 N/m and contact mode was employed. A Merlin Compact SEM system (Zeiss, Germany) was employed to detect the machined structures on a large scale. Schematic of the SERS substrate basic

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

• penetrating a viscoelastic solid in an intermittent-contact manner, which is a problem relevant to nanoscale spectroscopy techniques, such as tapping-mode AFM [34][35]. In standard tapping-mode AFM, a cantilever is harmonically excited either by imposing an oscillatory motion at the base (acoustic excitation

• tip trajectory for an AFM cantilever interacting with a viscoelastic surface in tapping-mode AFM (simulation details are provided in the figure caption). The instantaneous tip–sample distance, taking as reference the undeformed sample surface, is approximately given by: where Zeq refers to the average

• tip–sample position, A is the tapping amplitude, ω is the excitation frequency, and Asin(ωt) = z(t) is the instantaneous tip deflection. We have omitted the phase term, usually expressed as a phase lag between cantilever excitation and response, due to the sample-oriented analytical approach that we

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

• infinitely rigid AFM cantilever, wait until a steady-sliding regime is established, and discard the initial part affected by transients. For the remaining part of the simulation, we record the total force experienced by the slider as a function of time. This force has fluctuations as a result of collisions

• cantilever. In that scheme a stick-slip to smooth-sliding transition can also be investigated, especially at low speed (see Appendix “The static friction force”), allowing one to study in detail the nonlinear phenomena and mechanisms of phonon excitations that arise at slip times. The stick-slip regime and

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

• work, we present a detailed investigation of the magnetic properties of cobalt nanospheres grown on cantilever tips by focused electron beam induced deposition (FEBID). The cantilevers are extremely soft and the cobalt nanospheres are optimized for magnetic resonance force microscopy (MRFM) experiments

• strong field gradients from the magnetic probe [46] and ultra-soft cantilevers [47] are required. Therefore, the magnetic probe should be precisely located at the apex of the cantilever and be as small as possible to gain spatial resolution, and it should have as high magnetization as possible to

• is, the apex of the cantilever (Olympus BioLever, around 30 nm in size). We have scanned the beam over a circular area centered on the apex of the cantilevers and varied the radius of the circular area being scanned and the beam scanning time to obtain the different targeted diameters. The diameter

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

• complexity in the interpretation of the measurements as quantitative mechanical properties, the mechanical parameters (contact-resonance frequency and quality factor) of the fabricated samples are used in this study, whereby the same cantilever and imaging conditions are used for all samples, which enables

• discussion of their relative properties and changes. Figure 2 shows a summary of the mechanical parameters for thick and thin samples using the same cantilever and characterizing the samples in a random sequence. It is known, from macroscopic tensile testing, that the addition of nanoclays increases 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

• Inc., Orem, Utah, USA) were used for instrument calibration. AFM AFM measurements were performed with a traceable atomic force microscope that uses two integrated optical interferometry systems for detecting the deflection of the cantilever and for measuring the vertical motion of the piezoelectric

• laser (λ = 632.8 nm). Two parallel mirrors are required for the interferometer; one for each optical path. One mirror is rigidly connected to the PZT tube that moves the cantilever, and the other forms the sample holder. The interferometer is a double pass interferometer with each optical path having

• a temperature-controlled environment (20 ± 0.01 °C). Nanosensors PPP-NCLR tips (i.e., point probe plus non-contact long cantilever reflex coating) with nominal tip radius <10 nm were used. The AFM images were numerically corrected for tilt using the “mean plane subtraction” and “correction of

Air–water interface of submerged superhydrophobic surfaces imaged by atomic force microscopy

• Markus Moosmann,
• Thomas Schimmel,
• Wilhelm Barthlott and
• Matthias Mail

Beilstein J. Nanotechnol. 2017, 8, 1671–1679, doi:10.3762/bjnano.8.167

• cantilevers on the right-hand side marked in grey. Below the lower cantilever the sample is already wetted (Wenzel state), as marked with white crosses. The rest of the sample shows air retention (Cassie–Baxter state). Figure 4b was taken after three minutes. In the upper left area, the air layer has

• collapsed. After a duration of an additional 12 minutes, the wetted area increased (Figure 4c) until it finally reached the middle cantilever (Figure 4d). This wetted area advancement occurred stepwise and erratically. Noticeably, the interface separating the areas of air retention from the wetted areas are

• deflection of the cantilever is detected. With the cantilever calibrated, the deflection is automatically translated into the corresponding force. Considering that not only the cantilever but also the air–water interface acts according to Hooke’s law, we expect the pinning behavior to be relevant (as

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

• imaging because an increase of the speed can cause a loss of the tip–sample interaction and/or the annihilation of the cantilever tapping vibration, particularly when the imaging size is large. Existing efforts on high-speed TM imaging [6][7][8][9] only led to a speed increase up to three times at the

• hardware improvements via the use of high-bandwidth piezo actuators and cantilever are only applicable for small-size imaging (less than 30% of the imaging size of regular AFMs [14]), and the existing algorithm improvement based on advanced control techniques may lead to a potential sample deformation and

• maintaining the image quality and keeping the average tip–sample interaction force at the minimum level for stable cantilever tapping. AMLM imaging is fundamentally different from current efforts to high-speed TM imaging [6][8][15][16] insofar through the introduction of the control of the averaged cantilever

A review of demodulation techniques for amplitude-modulation atomic force microscopy

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

Beilstein J. Nanotechnol. 2017, 8, 1407–1426, doi:10.3762/bjnano.8.142

• used digital processing system. As a crucial bandwidth-limiting component in the z-axis feedback loop of an atomic force microscope, the purpose of the demodulator is to obtain estimates of amplitude and phase of the cantilever deflection signal in the presence of sensor noise or additional distinct

• nonlinear tip–sample forces acting on the cantilever, a feedback loop has to be employed in order to maintain a fixed setpoint with respect to the sample; the controller performs disturbance rejection by commanding a nanopositioner in its vertical direction. As the high-frequency cantilever deflection

• signal cannot be controlled directly, low-frequency measurables such as the change in oscillation amplitude in amplitude-modulation AFM [11] have to be employed. Other feedback variables such as the shift in cantilever resonance frequency in frequency-modulation AFM [13] or the phase shift in phase

Miniemulsion copolymerization of (meth)acrylates in the presence of functionalized multiwalled carbon nanotubes for reinforced coating applications

• Bertha T. Pérez-Martínez,
• Lorena Farías-Cepeda,
• Víctor M. Ovando-Medina,
• José M. Asua,
• Lucero Rosales-Marines and
• Radmila Tomovska

Beilstein J. Nanotechnol. 2017, 8, 1328–1337, doi:10.3762/bjnano.8.134

• mechanical thermal analyzer (DMTA, Triton Technology, Tritec 2000 DMTA). The scans were performed at a frequency of 1 Hz with a heating rate of 4 °C min−1 and the storage and loss moduli were measured. The measurements were run in single-cantilever bending mode with a displacement of 0.005 mm and a length

Study of the correlation between sensing performance and surface morphology of inkjet-printed aqueous graphene-based chemiresistors for NO₂ detection

• F. Villani,
• C. Schiattarella,
• T. Polichetti,
• R. Di Capua,
• F. Loffredo,
• B. Alfano,
• M. L. Miglietta,
• E. Massera,
• L. Verdoliva and
• G. Di Francia

Beilstein J. Nanotechnol. 2017, 8, 1023–1031, doi:10.3762/bjnano.8.103

• measurements have been collected over two weeks. Atomic force microscopy (AFM) images of the fabricated devices (substrates and deposited graphene) have been taken by means of an XE100 Park instrument operating in non-contact mode (amplitude modulation, silicon nitride cantilever from Nanosensor) at room

Vapor-phase-synthesized fluoroacrylate polymer thin films: thermal stability and structural properties

• Paul Christian and
• Anna Maria Coclite

Beilstein J. Nanotechnol. 2017, 8, 933–942, doi:10.3762/bjnano.8.95

• . The integration time was set to one minute, meaning that a temperature resolution of 2 °C could be achieved. Atomic force micrographs were taken in noncontact mode on a Nanosurf easyScan 2, equipped with a PPP-NCLR-10 cantilever (NanoWorld AG, Switzerland). The data are corrected for artifacts with

Functional dependence of resonant harmonics on nanomechanical parameters in dynamic mode atomic force microscopy

• Federico Gramazio,
• Matteo Lorenzoni,
• Francesc Pérez-Murano,
• Enrique Rull Trinidad,
• Urs Staufer and
• Jordi Fraxedas

Beilstein J. Nanotechnol. 2017, 8, 883–891, doi:10.3762/bjnano.8.90

• cantilevers of an atomic force microscope (AFM) as a function of relevant parameters such as the cantilever force constant, tip radius and free oscillation amplitude as well as the stiffness of the sample’s surface. The simulations reveal a universal functional dependence of the amplitude of the 6th harmonic

• below 20 GPa). Keywords: atomic force microscopy; metrology; multifrequency; nanomechanics; Introduction When an AFM cantilever oscillating freely and harmonically at a given frequency f and amplitude A1 approaches a solid surface, the oscillation becomes anharmonic due to the non-linear interaction

• , represented by the force field Fts, between the cantilever tip and the surface [1]. Thus, the time dependent trajectory a(t) of the cantilever tip, which can be expressed in the harmonic limit by a(t) = A1cos(2πft), is transformed into a Fourier series with harmonic oscillations of amplitudes An and

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

• Gheorghe Stan,
• Richard S. Gates,
• Qichi Hu,
• Kevin Kjoller,
• Craig Prater,
• Kanwal Jit Singh,
• Ebony Mays and
• Sean W. King

Beilstein J. Nanotechnol. 2017, 8, 863–871, doi:10.3762/bjnano.8.88

• probe tip in contact with the sample. The repetition rate of the IR laser is tuned to a contact resonance of the AFM cantilever to maximize the oscillation amplitude of the cantilever. By sweeping the IR laser over the wavelengths of interest and monitoring changes in the amplitude of the AFM probe tip

• angle of 60° from the front of the AFM probe, and swept continuously over the wavenumber range of interest [39]. The AFM-IR spectra were collected by tuning the repetition rate of the QCL to match a contact resonance of the AFM cantilever, typically the second flexural mode of the cantilever at ca. 180

• and 90 nm patterned fins by mechanically vibrating the tip–sample contact from the base of the cantilever [34]. The AFM probe used for these measurements was a SEIH PPP probe (NanoSensors, Neuchatel, Switzerland) with the free (out of contact) first two eigenmode frequencies at 102.7 kHz and 642.6 kHz

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

• between a liquid drop and rough surfaces using a conventional atomic force microscope. In this method, a micrometric liquid mercury drop is attached to an AFM tipless cantilever to measure the force required to pull this drop off a rough surface. We test the method with two surfaces: a square array of

• the colloidal particle on a tipless cantilever. The force required to pull the drop off a surface is measured in a nitrogen atmosphere to avoid water capillary interactions. The liquid probe is close to what would be expected to be a smooth probe down to the atomic level. Recently, we reported an

• break during pull-off and results in a small residual water droplet on the surface. In the present study, we choose mercury as the liquid because it presents many advantages. Hg possesses a very high surface tension and negligible evaporation, plus it is relatively easy to attach to a tipless cantilever

3D Nanoprinting via laser-assisted electron beam induced deposition: growth kinetics, enhanced purity, and electrical resistivity

• Brett B. Lewis,
• Robert Winkler,
• Xiahan Sang,
• Pushpa R. Pudasaini,
• Michael G. Stanford,
• Harald Plank,
• Raymond R. Unocic,
• Jason D. Fowlkes and
• Philip D. Rack

Beilstein J. Nanotechnol. 2017, 8, 801–812, doi:10.3762/bjnano.8.83

• demonstrating this relationship is the angle between a grown vertical post and a cantilever arm, depicted as θ in Figure 2. This angle will be termed “segment angle” hereafter. The vertical pillar is grown by parking the electron beam at a particular spot for 8 seconds, and the segment is grown off the pillar

• reduction (see Supporting Information File 1 for 3D examples). Pulsed laser irradiation and gas pressure both affect the growth rate and morphology of the EBID structures. A useful way to characterize this change is by fabricating a pillar + cantilever, or ‘segment’, using EBID. Figure 2 depicts the changes

• angle of 52° with respect to the plane containing the pillar and segment. For scale, the projection of each cantilever arm is 400 nm. BF STEM images of a) an as-deposited EBID segment with a 10.4 ms dwell time per pixel and in situ LAEBID performed at various dwell times per point including b) 10.4 ms

Phospholipid arrays on porous polymer coatings generated by micro-contact spotting

• Sylwia Sekula-Neuner,
• Monica de Freitas,
• Lea-Marie Tröster,
• Tobias Jochum,
• Pavel A. Levkin,
• Michael Hirtz and
• Harald Fuchs

Beilstein J. Nanotechnol. 2017, 8, 715–722, doi:10.3762/bjnano.8.75

• variety of bio-applications. Keywords: microcontact cantilever spotting; phospholipids; polymeric porous support; polymethacrylate; Introduction Starting with the creation of high density peptide microarrays in the 1990s [1] the development of arrays with DNA molecules and antibodies has produced a

• novel antiandrogens affinity to the receptor [6] and effects on the receptor’s poly Q-extended mutations [23]. Results and Discussion Microchannel cantilever spotting (µCS) with phospholipids In order to establish best conditions for microchannel cantilever spotting (µCS) of phospholipids with the SPTs

Optimizing qPlus sensor assemblies for simultaneous scanning tunneling and noncontact atomic force microscopy operation based on finite element method analysis

• Omur E. Dagdeviren and
• Udo D. Schwarz

Beilstein J. Nanotechnol. 2017, 8, 657–666, doi:10.3762/bjnano.8.70

• while NC-AFM uses the perturbation that surface forces impose on the vibration of a cantilever to sense the proximity of the surface from a tip located at the end of the cantilever [12][13][14]. It is even possible to conduct simultaneous STM and NC-AFM experiments, which deliver complementary