A simple and efficient quasi 3-dimensional viscoelastic model and software for simulation of tapping-mode atomic force microscopy

• Santiago D. Solares

Beilstein J. Nanotechnol. 2015, 6, 2233–2241, doi:10.3762/bjnano.6.229

• modified to implement other controls schemes in order to aid in the interpretation of AFM experiments. Keywords: atomic force microscopy (AFM); modeling; multifrequency; multimodal; polymers; simulation; spectroscopy; standard linear solid; tapping-mode AFM; viscoelasticity; Introduction The

• rate-dependent dissipative processes. Viscoelasticity, in particular, is a very difficult phenomenon to deal with accurately within AFM spectroscopy, whereby one tries to extract material properties following a set of measurements in which generally one parameter is varied while keeping all other

• number of reasons. First, viscoelasticity itself is a difficult-to-quantify behavior at the nanoscale. In continuum measurements it is common to describe viscoelastic behavior in terms of the loss and storage moduli, but strictly speaking, these quantities are only meaningful in the case when a

Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

• Jana Vlachová,
• Rebekka König and
• Diethelm Johannsmann

Beilstein J. Nanotechnol. 2015, 6, 845–856, doi:10.3762/bjnano.6.87

• related to linear viscoelasticity, meaning that the corresponding stresses are proportional to displacement (Figure 2C). While such viscous processes are not contained in the CM model, they can be added into it in an ad hoc manner (see Equation 12). In the Results and Discussion section, we address a

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

• separated in long range and short range. The user has the option of combining a long range with a short range interaction to produce the full tip–surface force. It is also possible to add one or several non-conservative interactions such as adhesion hysteresis and/or viscoelasticity. We briefly describe the

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• due to the fact that the QCM detects changes in the viscoelasticity close to the resonator’s surface, which affects the basolateral side of the cell monolayer. Hence, it probably requires larger numbers of particles to generate a change in cell elasticity. In contrast, AFM indentation experiments

Modeling viscoelasticity through spring–dashpot models in intermittent-contact atomic force microscopy

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

Beilstein J. Nanotechnol. 2014, 5, 2149–2163, doi:10.3762/bjnano.5.224

• /bjnano.5.224 Abstract We examine different approaches to model viscoelasticity within atomic force microscopy (AFM) simulation. Our study ranges from very simple linear spring–dashpot models to more sophisticated nonlinear systems that are able to reproduce fundamental properties of viscoelastic surfaces

• deformation frequencies (descriptions of tip–sample model behaviors in the context of multifrequency AFM require detailed studies and are beyond the scope of this work). Keywords: atomic force microscopy; creep; dissipated energy; multifrequency; stress relaxation; tapping mode; viscoelasticity

• techniques operate in a regime of quasi-linear tip–sample forces by using very small cantilever oscillation amplitudes, but as a result only provide linear viscoelasticity information and characterization can be slow for CR-AFM and BE-AFM due to the pixel-based measurement procedures used. Significant

Equilibrium states and stability of pre-tensioned adhesive tapes

• Carmine Putignano,
• Luciano Afferrante,
• Luigi Mangialardi and
• Giuseppe Carbone

Beilstein J. Nanotechnol. 2014, 5, 1725–1731, doi:10.3762/bjnano.5.182

• theoretical investigations about rough contact mechanics [25][26][27][28][29], the role of roughness in this kind of systems is not yet well understood. Furthermore, viscoelasticity, which entails prominent effects in terms of friction and contact anisotropy [30][31], has not yet been included in analytical

Probing viscoelastic surfaces with bimodal tapping-mode atomic force microscopy: Underlying physics and observables for a standard linear solid model

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 1649–1663, doi:10.3762/bjnano.5.176

• properties and the AFM observables. The physics of the tip–sample interactions and its effect on the observables are illustrated and discussed, and a brief research outlook on viscoelasticity measurement with intermittent-contact AFM is provided. Keywords: amplitude-modulation; bimodal; dissipation

• ; frequency modulation; multi-frequency atomic force microscopy; viscoelasticity; standard linear solid; Introduction Atomic force microscopy (AFM) has developed considerably since its introduction in the mid-1980s, and today constitutes one of the most powerful and versatile tools in nanotechnology [1][2][3

• ]. Besides topographical imaging, it is also commonly used to map conservative and dissipative interactions across nanoscale surfaces, from which compositional contrast can be inferred. For soft samples the contrast is often associated with viscoelasticity for which measurements are most commonly carried out

Multi-frequency tapping-mode atomic force microscopy beyond three eigenmodes in ambient air

• Santiago D. Solares,
• Sangmin An and
• Christian J. Long

Beilstein J. Nanotechnol. 2014, 5, 1637–1648, doi:10.3762/bjnano.5.175

• carried out and the apparent robustness of our results, the non-uniformity of successive tip–sample impacts, the nonlinear coupling of the various eigenmodes, as well as time-dependent tip–sample behaviors such as viscoelasticity suggest that unless single-cycle techniques [16][18][30] can be implemented

Frequency, amplitude, and phase measurements in contact resonance atomic force microscopies

• Gheorghe Stan and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 278–288, doi:10.3762/bjnano.5.30

• is provided. Keywords: contact-resonance AFM; dynamic AFM; frequency modulation; phase-locked loop; viscoelasticity; Introduction A number of atomic force microscopy (AFM) variants have emerged since the introduction of the original technique in 1986 [1]. Besides topographical acquisition and

• sensitivity. However, with the exception of small-amplitude FM-AFM [28][29] in which the tip–sample force gradient can be measured directly, the mapping of Vts and Pts in intermittent-contact imaging generally only provides a qualitative map of surface viscoelasticity. In this work the focus is on the CR-AFM

Dynamic nanoindentation by instrumented nanoindentation and force microscopy: a comparative review

• Sidney R. Cohen and
• Estelle Kalfon-Cohen

Beilstein J. Nanotechnol. 2013, 4, 815–833, doi:10.3762/bjnano.4.93

• Sidney R. Cohen Estelle Kalfon-Cohen Department of Chemical Research Support, Weizmann Institute of Science, POB 26, Rehovot, ISRAEL 76100 School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138, USA 10.3762/bjnano.4.93 Abstract Viscoelasticity is a complex yet

• principles in nanoindentation, and compares and contrasts these two techniques as they are used for characterization of viscoelastic processes at the nanoscale. Keywords: atomic force microscopy; loss modulus; nanoindentation; storage modulus; viscoelasticity; Review Introduction Understanding and

• , which is in turn used to express the dynamic elastic moduli as defined above. This shift is frequency-dependent, as the various modes of internal friction of the polymer are excited at distinct characteristic times. In order to probe the viscoelasticity at the nanoscale analogous techniques are applied

Multiple regimes of operation in bimodal AFM: understanding the energy of cantilever eigenmodes

• Daniel Kiracofe,
• Arvind Raman and
• Dalia Yablon

Beilstein J. Nanotechnol. 2013, 4, 385–393, doi:10.3762/bjnano.4.45

• significantly different to the interaction probed by the second eigenmode (e.g., due to viscoelasticity). Alternatively, it could be that there is a difference in the cantilever dynamics at the fourth eigenmode such that it responds to the exact same tip–sample interaction in a different way. Next we show

Towards 4-dimensional atomic force spectroscopy using the spectral inversion method

• Jeffrey C. Williams and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 87–93, doi:10.3762/bjnano.4.10

• is a promising approach due to its dynamic nature, robustness, relative simplicity and previous successes. Keywords: atomic force microscopy; spectral inversion; spectroscopy; torsional harmonic cantilever; viscoelasticity; Introduction Besides topographical imaging, a popular application of atomic

• with attractive van der Waals interactions. Results and Discussion Characterization of rate-dependent phenomena The ability to recover rate-dependent signatures of the tip–sample forces presents a unique opportunity to study phenomena such as plasticity, viscoelasticity and biomolecular binding and

• well suited to study stress relaxation. (While this paper is not intended to be a study of surface viscoelasticity, we briefly illustrate the use of slightly more elaborate surface models.) Instead, one could, for example, use the standard linear solid (SLS) model, which is a combination of the Maxwell

Growth behaviour and mechanical properties of PLL/HA multilayer films studied by AFM

• Cagri Üzüm,
• Johannes Hellwig,
• Narayanan Madaboosi,
• Dmitry Volodkin and
• Regine von Klitzing

Beilstein J. Nanotechnol. 2012, 3, 778–788, doi:10.3762/bjnano.3.87

• ; viscoelasticity; Young’s modulus; Introduction Polyelectrolyte multilayers (PEMs) have been studied intensely for the past two decades [1][2]. Despite their complex structure and wide range of applicability, PEMs can be prepared simply by alternating deposition of polycations and polyanions by dipping/spraying a

• probe to the surface. This point is shown in Figure 4a. Viscoelasticity measurements were performed with some principle differences and the details are given in the Discussion section. (a) Top camera view of the cantilever and the scratch on the film (delimited with the dashed lines). The circle points

Mapping mechanical properties of organic thin films by force-modulation microscopy in aqueous media

• Jianming Zhang,
• Zehra Parlak,
• Carleen M. Bowers,
• Terrence Oas and
• Stefan Zauscher

Beilstein J. Nanotechnol. 2012, 3, 464–474, doi:10.3762/bjnano.3.53

• is thus not a result of the substrate viscoelasticity alone. The force, amplitude, and phase measurements shown in Figure 2 were carried out on thin gold surfaces whose apparent stiffness can be represented by a simple spring. Even in this simple case, a quantitative description of the cantilever

• , while the adhesion force on the protein surface is within the noise level of the measurement. This justifies the use of a Hertzian contact mechanics model, as done here. Our approach currently does not capture the viscoelasticity of the protein or the response of the cantilever to a viscoelastic contact

Pulse-response measurement of frequency-resolved water dynamics on a hydrophilic surface using a Q-damped atomic force microscopy cantilever

• Masami Kageshima

Beilstein J. Nanotechnol. 2012, 3, 260–266, doi:10.3762/bjnano.3.29

• Masami Kageshima Department of Physics, Tokyo Gakugei University, 4-1-1 Nukui-kita-machi, Koganei, Tokyo 184-8501, Japan 10.3762/bjnano.3.29 Abstract The frequency-resolved viscoelasticity of a hydration layer on a mica surface was studied by pulse-response measurement of a magnetically driven

• –sample system. The significant viscoelasticity spectrum of the hydration layer was successfully derived in a frequency range below 100 kHz by comparison of data obtained at a distance of 300 nm from the substrate with those taken in the proximity of the substrate. A positive value of the real part of the

• stiffness was determined and is attributed to the reported solidification of the hydration layers. Keywords: atomic force microscopy; hydration; pulse-response; quality-factor control; viscoelasticity; Introduction Liquid solvation is a phenomenon common to a large variety of liquid–solid interfaces [1

Mechanical characterization of carbon nanomembranes from self-assembled monolayers

• Xianghui Zhang,
• André Beyer and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2011, 2, 826–833, doi:10.3762/bjnano.2.92

• . Viscoelasticity Macroscopic viscoelasticity and local viscoelastic properties of soft materials have been intensively studied, for example in polymer networks or in nuclei of biological cells [22][23]. Gaining new insights into the viscoelastic behavior of one-nanometer-thick membranes requires a method with

• values of ~0.65%, ~1.2% and ~1.7%. The hysteresis loop becomes more and more pronounced with the increase in the maximum tensile strain of each cycle. Hysteresis is one major characteristic of viscoelasticity and is associated with the energy that is dissipated as heat in the loading cycles. The specific