Pull-off and friction forces of micropatterned elastomers on soft substrates: the effects of pattern length scale and stiffness

• Peter van Assenbergh,
• Marike Fokker,
• Julian Langowski,
• Jan van Esch,
• Marleen Kamperman and
• Dimitra Dodou

Beilstein J. Nanotechnol. 2019, 10, 79–94, doi:10.3762/bjnano.10.8

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• force–distance curves are measured at every pixel in the scan range, and the peak forces below the baselines in the retracting line of the force–distance curves are then used for adhesion mapping. According to Equation 1, once the AFM tip is biased, the adhesion force between the tip and the sample

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

• nanocomposite. As discussed previously, the force applied by the tip to the surface increases with the use of higher eigenmodes and by increasing their free amplitude. Supporting Information File 1, Figure S5 shows the results of a virtual AFM numerical simulation, where the increase in peak forces as the free

Scaling law to determine peak forces in tapping-mode AFM experiments on finite elastic soft matter systems

• Horacio V. Guzman

Beilstein J. Nanotechnol. 2017, 8, 968–974, doi:10.3762/bjnano.8.98

• . A closed-form analytical equation to estimate the tip–sample peak forces while imaging soft materials in liquid environment and within an elastic deformation regime has been deduced. We have combined a multivariate regression method with input from the virial–dissipation equations and Tatara’s

• operating conditions to image soft matter with high spatial resolution in tapping-mode AFM. Keywords: AFM in liquid; AFM theory; bidimensional elastic models; multivariate regression; neuronal networks; operational AFM parameters; parametrical equation; peak forces; soft matter; Introduction Amplitude

• invasiveness of the measurement. The parametrical equation obtained by Raman et al. has been based on the Hertzian mechanics for air and vacuum environments [21]. It has been also adapted to estimate the experimental peak forces of viral capsids (ca. 1 GPa) in liquid [22]. However, those parametrical

Analysis and modification of defective surface aggregates on PCDTBT:PCBM solar cell blends using combined Kelvin probe, conductive and bimodal atomic force microscopy

• Hanaul Noh,
• Alfredo J. Diaz and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 579–589, doi:10.3762/bjnano.8.62

• aggregates, avoiding additional sample modification. Typically, multifrequency AFM uses the first eigenmode of the cantilever to control the tip–sample distance and acquire the topography, and higher eigenmodes to measure additional properties [37][38]. We have also previously shown that the peak forces can

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

• the tip and the sample with increasing indentation is greatly diminished. Notice that the peak forces of the green trace in Figure 10d are lower than those of the red trace, despite the fact that the indentation is greater for the green trace, as shown in Figure 10e. This occurs due to the attractive

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

• ) with respect to any of the kinetic energies of the other modes. However, the increase in compositional sensitivity happens at the expense of increasing the peak forces. (a) Scheme of the excitation and detection signals in bimodal AM configuration. (b) Definition of phase shifts in bimodal AM for the

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

• material properties [25][26][27] in obtaining the maximum force. Simulations can generate maps that provide the estimation of the peak forces for a large variety of conditions [27][28]. The range of applicability of the force reconstruction methods has also been verified by numerical simulations [29]. The

• devise the optimal experimental conditions in terms of amplitudes, peak forces, material property sensitivity and spatial resolution, or to explain the experimental data in standard and non-standard dynamic AFM configurations. The code is written in Python/SciPy, which is embedded with open source

• peak forces are about −92 and 112 pN, respectively. One useful feature provided by dForce is the capability to combine different data in a single plot. Figure 2d shows the cantilever deflection, the velocity and the force. Coexistence of interaction regimes The existence of different interaction

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

• penetration is fixed for different values of A2, the peak forces still differ considerably for successive impacts since the trajectory is bimodal. Furthermore, there are some impacts during which the interaction between the tip and the sample is almost negligible (see, for example, the first impact for A2 = 4

• in the captions of Figure 11 and Figure 12 regarding the origin of the kinks in some of the traces). Additionally, Figure 11b, Figure 12b and Figure 13b suggest that the trends in dissipated energy and peak forces are not unique for each of the three SLS parameters. For example, an asymptotic

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

• regular impact when the eigenmode spacing is greater). Figure 9c shows the force trajectory for a large number of impacts, confirming that successive tip–sample interactions become more similar with greater eigenmode spacing. Notice how the peak forces over a large number of fundamental oscillations in

• = 100 nm, A2 = A3 = 3 nm) and eigenmodes 1, 4 and 9 (A1 = 100 nm; A4 = A9 = 3 nm) with Asetpoint ≈ 80%; (b) close-up of the lowest portion of the tip trajectory for the above cases; (c) illustration of force trajectories for the above cases (notice how the peak forces in successive impacts become more

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

• used): (a) maximum indentation depth vs cantilever force constant; (b) peak forces corresponding to (a); (c) maximum indentation vs cantilever quality factor, Q (unrealistically low values of Q were chosen to illustrate the effect of high damping); (d) maximum indentation vs first and second eigenmode

• setpoint, or changes in the free oscillation amplitude. The first option is not practical since it requires a cantilever changeover. The second option is feasible using the Q-control method but requires additional electronics [20][21]. The third option does not work indefinitely since indentation and peak

• forces vary in a non-monotonic fashion as the cantilever is lowered towards the surface, as illustrated by all plots in Figure 2 [9]. The fourth option is also relatively limited in the additional indentation depth that can be accomplished as shown in Figure 2d (black, blue, red and dotted black traces

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

• ]. Accordingly, relatively high peak forces, of the order of 1–100 nN, are required [22][23] to excite higher harmonics above the noise level. In order to address this issue, in 2004 Rodriguez and García [23] proposed to drive the second higher flexural mode of the cantilever with an external drive. In this way

• orthogonality. Furthermore 2(N−1) observables, i.e., higher harmonic amplitudes and phases, are made available even with peak forces no higher than 200 pN, as they are required [25][39] for high resolution and minimally invasive imaging of soft matter. Thermal fluctuations are also considered here in order to

• frequencies when A0n = 100 pm. When A0n = 1 pm (squares), however, the values of are not exactly 180° or 0° for some n. Thus, the values are now sensitive to the Hamaker values or tip–sample forces. The peak forces were 140 pN (circles) and 160 pN (triangles) respectively. The loss of phase sensitivity to

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

• Horacio V. Guzman Ricardo Garcia Instituto de Ciencia de Materiales de Madrid, CSIC, Sor Juan Ines de la Cruz 3, 28049 Madrid, Spain 10.3762/bjnano.4.96 Abstract The peak forces exerted on soft and rigid samples by a force microscope have been modeled by performing numerical simulations of the

• , the use of force inversion methods has not been generalized in AM-AFM because the accuracy of some of the above methods is still under study. On the other hand, numerical simulations have been used to determine the maximum repulsive interaction forces, which are referred to as peak forces hereafter

• [19][20][21][22][23]. An analytical scaling law has been deduced to calculate the peak forces in air [21]. This method has been applied to determine the force on viral capsids in liquid [24]. However, the above expressions are often constrained to a specific interaction force model, such as Hertzian

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

• ) containing only 58%. We subjected each of the three polymorphs to the four pulling modes in Figure 2, and recorded the peak forces exerted (as shown in Figure 4). Force profiles from which the highest peak forces are measured for each polymorph during the four different SMD pulling modes are shown in Figure

•  5. All three fibril polymorphs demonstrate an anisotropic response to mechanical probing. Similar mean peak forces are required to break the fibrils when the hydrogen-bond networks are probed (“shear” and “stretch”). There are however, very distinct responses in the SMD simulations that probe the

• 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