Nanoscale effects in the characterization of viscoelastic materials with atomic force microscopy: coupling of a quasi-three-dimensional standard linear solid model with in-plane surface interactions

• Santiago D. Solares

Beilstein J. Nanotechnol. 2016, 7, 554–571, doi:10.3762/bjnano.7.49

• illustrates the time-dependent relaxation behavior of the surface element directly under the tip (Figure 8b), the oscillation amplitude and phase (Figure 8c and Figure 8d, respectively), the peak force within one fundamental oscillation (Figure 8e), and the maximum indentation within one fundamental

• as the cantilever position changes, as can be observed by inspection of the green trace in Figure 10d (peak force) and Figure 10e (maximum indentation). It is interesting to observe also that the order of the traces in Figure 10d is not the same as that of Figure 10e (the order of the red and green

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

• tip–sample force, instantaneous amplitude, phase). In addition, the program also produces a second output file at the end of the run, which contains the amplitude, phase, peak force and peak indentation recorded for each value of the cantilever height. Figure 6 provides an example of the spectroscopy

• peak force vs cantilever position (these two quantities are not directly observable in a spectroscopy experiment). The simulation parameters are the same as for monomodal AFM in Figure 4. Supporting Information Supporting Information consists of a ZIP archive containing three files: A program manual

Nano-contact microscopy of supracrystals

• Adam Sweetman,
• Nicolas Goubet,
• Ioannis Lekkas,
• Marie Paule Pileni and
• Philip Moriarty

Beilstein J. Nanotechnol. 2015, 6, 1229–1236, doi:10.3762/bjnano.6.126

• , maintaining the same tip–sample separation. Repeating the force–distance measurements (Figure 2E), we observed a slight modification to the tip–sample force profiles, although we cannot rule out that the reduced peak force could also arise from a minor change in the tip apex. More striking was the observation

Optimization of phase contrast in bimodal amplitude modulation AFM

• Mehrnoosh Damircheli,
• Amir F. Payam and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2015, 6, 1072–1081, doi:10.3762/bjnano.6.108

• excitation improves the phase contrast (Figure 9c). This seems an advantage of trimodal with respect to bimodal AM, however, this happens at the expense of introducing additional electronic hardware and increasing the peak force. A more detailed study is needed to stablish the advantages/disadvantages of

Self-assembled anchor layers/polysaccharide coatings on titanium surfaces: a study of functionalization and stability

• Ognen Pop-Georgievski,
• Dana Kubies,
• Josef Zemek,
• Neda Neykova,
• Roman Demianchuk,
• Eliška Mázl Chánová,
• Miroslav Šlouf,
• Milan Houska and
• František Rypáček

Beilstein J. Nanotechnol. 2015, 6, 617–631, doi:10.3762/bjnano.6.63

• characterization was performed on a Dimension ICON (Bruker, USA) system in peak force tapping mode in air using silicon probes (TAP150A, Bruker, USA) with a typical force constant of 5 N∙m−1. The images were taken using a scan rate in the range of 0.5−1.2 Hz and a peak force set point of 0.02−0.2 V. Surface

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

• instantaneous deflection and tip–surface force, velocity, virial, dissipated energy, sample deformation and peak force as a function of time or distance. The simulator includes a variety of interactions and contact mechanics models to describe AFM experiments including: van der Waals, Hertz, DMT, JKR, bottom

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

• on soft samples, but becomes subject to low-signal-to-noise ratio limitations as the sample becomes stiffer [38]. Finally, the peak-force AFM method [39], a hybrid between contact- and intermittent-contact AFM, also measures the tip–sample force in real time during approach and retract of the tip by

• the force minima for a given frequency in Figure 4a) decreases with increasing frequency as the hysteresis loop area also decreases (see Figure 4d). Additionally, the peak force increases. This is because at faster time scales the system behavior becomes more elastic and less viscous. This frequency

• proceeds in the counterclockwise direction); (b) tip–sample force vs normalized time; (c) surface recovery vs normalized time; (d) peak force and dissipated energy per cycle vs cantilever frequency (the two traces are color coded with their respective axes). The SLS parameters were Kinf = Ko = 7.5 N/m and

Trade-offs in sensitivity and sampling depth in bimodal atomic force microscopy and comparison to the trimodal case

• Babak Eslami,
• Daniel Ebeling and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 1144–1151, doi:10.3762/bjnano.5.125

• cases was 17 nm, with an amplitude setpoint of 80% for attractive regime imaging and 50% for repulsive regime imaging. Simulations of maximum indentation and peak force (see section Methods below for details on the numerical simulations of the cantilever dynamics as well as the tip–sample force model

A nanometric cushion for enhancing scratch and wear resistance of hard films

• Katya Gotlib-Vainshtein,
• Olga Girshevitz,
• Chaim N. Sukenik,
• David Barlam and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2014, 5, 1005–1015, doi:10.3762/bjnano.5.114

• layer used for these purposes was about 700 nm, based on cross-sectional FIB measurements. The Young's modulus of PDMS after hexane evaporation was measured with Peak-Force QNM® and found to be the same as in those samples with 10 µm thickness that had been obtained with no dilution with hexane – 1.5

• indenter was used to image the area after the nanomechanical tests. The modulus of the PDMS was measured using PeakForce QNM (Quantitative Nanomechanical property mapping), an extension of the Peak Force Tapping® mode, using ScanAsyst-air probes (force constant of 0.4 N/m, Digital Instruments, Santa

The softening of human bladder cancer cells happens at an early stage of the malignancy process

• Jorge R. Ramos,
• Joanna Pabijan,
• Ricardo Garcia and
• Malgorzata Lekka

Beilstein J. Nanotechnol. 2014, 5, 447–457, doi:10.3762/bjnano.5.52

• peak force; in this case, it was set to 1 nN. The curves were acquired with a speed of 5 μm/s. The force-versus-indentation curves were obtained by subtracting the force curves recorded on a stiff glass surface from the ones recorded on the cell surfaces. The elastic modulus (Young’s modulus) was

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

• superposition of normalized single events (n = 3). A,B) Typical single stretching event with one and two kinks (type 2), the insets are the proposed models. C,D) The frequency distributions of rupture force and rupture length of kinks in force curves with only one kink, respectively. A) Typical double-peak

• force curve. B) “type 3” (t3) force curve. C,D) histograms of the differences between the rupture forces and rupture lengths of the two continues peaks in t3 force curves. Mechanical responses composited by different type force curves. A) t1 + t2. B) t2 + t3. C) t1 + t3. D) t2 + t2 + t1 + t3

Unlocking higher harmonics in atomic force microscopy with gentle interactions

• Sergio Santos,
• Victor Barcons,
• Josep Font and
• Albert Verdaguer

Beilstein J. Nanotechnol. 2014, 5, 268–277, doi:10.3762/bjnano.5.29

• harmonics act as simultaneous contrast channels that are sensitive to Hamaker, or chemical, variations. In Figure 3 the sensitivity of Δ when A0n = 1 pm is tested by varying H (a) from H1 = 0.2 × 10−19 J to H2 = 0.4 × 10−19 J (peak force variation of 29 pN, circles), (b) from H1 = 0.6 × 10−19 J to H2 = 0.8

• × 10−19 J (peak force variation of 8 pN, squares) and (c) from H1 = 1.2 × 10−19 J to H2 = 1.4 × 10−19 J (peak force variation of 3 pN, triangles). The shifts Δ are larger than 0.2° for all n provided the variations in peak force are large enough (circles). If the variations in the peak force are

• sufficiently small then Δ > 0.2° for some n only. Also, it can be deduced by inspection that, in general, Δ escalates with variations in peak force and changes non-linearly with variations in Hamaker since H2 − H1 = 0.2 × 10−19 J throughout in the figure. In fact, from Figure 3, the total contributions to the

Peak forces and lateral resolution in amplitude modulation force microscopy in liquid

• Horacio V. Guzman and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2013, 4, 852–859, doi:10.3762/bjnano.4.96

• microscopy; lateral resolution; nanomechanics; peak force; Introduction The high-resolution imaging of heterogeneous materials, in particular soft materials in liquid, by amplitude modulation atomic force microscopy (AM-AFM) is an active area of research in nanotechnology [1][2][3][4][5][6][7][8][9][10][11

• relatively rigid (2 GPa) materials for two different models of contact mechanics, namely Hertz [29] and Tatara [30][31][32]. We also provide a comparison between the numerical simulations and three analytical expressions [21][33][34]. The dependence of the peak force on a wide range of tip–microcantilever

• ≤ 5nm). AM-AFM operation at relatively high amplitudes can also lead to tip blunting [35][36]. The estimation of the peak force prior to performing the experiment could prevent tip damage. Results and Discussion Tip motion and contact time for soft and relatively rigid materials In AM-AFM the equation

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

• tapping mode, the “Quantitative Nanomechanical Peak Force” (QNM™) mode, where the force–separation curve is recorded at every image point and the topography mechanical properties (e.g., adhesion force, energy dissipation, deformation, DMT modulus or stiffness, peak force, phase shift) are simultaneously

Molecular dynamics simulations of mechanical failure in polymorphic arrangements of amyloid fibrils containing structural defects

• Hlengisizwe Ndlovu,
• Alison E. Ashcroft,
• Sheena E. Radford and
• Sarah A. Harris

Beilstein J. Nanotechnol. 2013, 4, 429–440, doi:10.3762/bjnano.4.50

• were carried out using the pulling geometries shown schematically in Figure 2 to probe the fibrils from different directions. Each pulling-mode simulation was repeated four times, and the mechanical properties were characterised by the average peak force measured over the four independent simulations

• hydrophobic core interactions (“peel” and “slide”). Hydrophobic core disruption: The largest mean peak forces for both hydrophobic core probing modes (“peel” and “slide”) were recorded for the Class1-P polymorph. The molecular basis behind the relative ranking in mean peak force between the polymorphs can be

• in each of the two stacked β-sheets, we observe a correlation between the mean peak force and the intersheet electrostatic interaction energies (Table 1) that arise due to the unique packing arrangements of the monomer β-strands. The Class1-P polymorph has the most favourable electrostatic energy

High-resolution nanomechanical analysis of suspended electrospun silk fibers with the torsional harmonic atomic force microscope

• Mark Cronin-Golomb and
• Ozgur Sahin

Beilstein J. Nanotechnol. 2013, 4, 243–248, doi:10.3762/bjnano.4.25

• unloading portion of the force distance-curve is the region between the peak force and the point where the force drops to 20% of the peak value. Initially, we calculated both the elastic modulus and spring constant values regardless of their appropriateness for describing local mechanical response. We

Modeling noncontact atomic force microscopy resolution on corrugated surfaces

• Kristen M. Burson,
• Mahito Yamamoto and
• William G. Cullen

Beilstein J. Nanotechnol. 2012, 3, 230–237, doi:10.3762/bjnano.3.26

• interaction is repulsive. This is rather unsatisfactory at present, as it would be preferable to have well-defined numerical values (even if unrealistically large), and then let the limits of the model be decided on physical grounds, i.e., peak force or stress on the tip apex, etc. 3 Calculation of frequency