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

• order to simultaneously acquire the topography and quantify the elasticity of a Ge(001) surface with high resolution [17]. Li and coworkers used a bimodal method in which the first eigenmode was driven by using the phase modulation scheme and the higher mode was driven in open loop, which allowed them

• to obtain images of the sample topography, energy dissipation and elasticity of polymer surfaces immersed in a liquid environment [16]. We have also reported experiments in which images of Vts and Pts were compared for different control schemes applied to the higher mode, including open loop

Influence of the PDMS substrate stiffness on the adhesion of Acanthamoeba castellanii

• Sören B. Gutekunst,
• Carsten Grabosch,
• Alexander Kovalev,
• Stanislav N. Gorb and
• Christine Selhuber-Unkel

Beilstein J. Nanotechnol. 2014, 5, 1393–1398, doi:10.3762/bjnano.5.152

• and position themselves [6]. Once grown on a substrate with defined elasticity, cells adapt their own elasticity to the elasticity of their environment [7]. But not only differentiated cells are influenced by substrate stiffness. For stem cells it has been demonstrated that their differentiation is

• polydimethylsiloxane (PDMS) substrates with Young’s moduli of 4 kPa, 29 kPa, and 128 kPa. These Young’s moduli were chosen in order to cover an elasticity range, for which a significant effect of substrate stiffness on the adhesion of mammalian cells has already been reported [1]. We systematically investigated the

• cool down to room temperature. Elasticity measurements Mechanical properties of PDMS substrates were determined by microindentation using a micro-force measurements device (Basalt-BT01, Tetra GmbH, Ilmenau, Germany) [24]. The recorded force–distance curves were used to calculate the Young’s modulus of

Physical principles of fluid-mediated insect attachment - Shouldn’t insects slip?

• Jan-Henning Dirks

Beilstein J. Nanotechnol. 2014, 5, 1160–1166, doi:10.3762/bjnano.5.127

• , a softer adhesive pad/substrate (with a lower elasticity) deforms more easily at a given external force, resulting in a larger contact area. This larger contact area again increases the radius of the mediating meniscus of the liquid (the liquid is pressed towards the outside of the pad), which then

Organic and inorganic–organic thin film structures by molecular layer deposition: A review

• Pia Sundberg and
• Maarit Karppinen

Beilstein J. Nanotechnol. 2014, 5, 1104–1136, doi:10.3762/bjnano.5.123

Insect attachment on crystalline bioinspired wax surfaces formed by alkanes of varying chain lengths

• Elena Gorb,
• Sandro Böhm,
• Nadine Jacky,
• Louis-Philippe Maier,
• Kirstin Dening,
• Sasha Pechook,
• Boaz Pokroy and
• Stanislav Gorb

Beilstein J. Nanotechnol. 2014, 5, 1031–1041, doi:10.3762/bjnano.5.116

• different characteristics of crystalline wax surfaces influence the attachment? We also measured adhesion (pull-off) forces of artificial adhesive systems on these surfaces. Here, tacky and deformable polydimethylsiloxane (PDMS) semi-spheres, having elasticity moduli similar to those of insect adhesive pads

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

• overlayer based on the elasticity of an underlying PDMS elastomer. To demonstrate the generality of the strategy, different substrates were coated with titania, with and without a soft underlayer. We have previously reported the deposition of thin and uniform titania films on Si, kapton, and

Fibrillar adhesion with no clusterisation: Functional significance of material gradient along adhesive setae of insects

• Stanislav N. Gorb and
• Alexander E. Filippov

Beilstein J. Nanotechnol. 2014, 5, 837–845, doi:10.3762/bjnano.5.95

• presented the combined study on the material structure and local mechanical properties in tarsal setae of the beetle Coccinella septempunctata and demonstrated the presence of a material gradient at the level of each single seta [12]. Setal elasticity modulus, probed by atomic force microscope (AFM), ranges

• sclerotised basal part of the seta, a rather pronounced longitudinal gradient of material composition was revealed. AFM-nanoindentation experiments have revealed rather low elasticity modulus at the setal tip (1.2 ± 0.3 MPa), but the high one at the setal base (2.43 ± 1.9 GPa) [12]. This information about the

Scale effects of nanomechanical properties and deformation behavior of Au nanoparticle and thin film using depth sensing nanoindentation

• Dave Maharaj and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2014, 5, 822–836, doi:10.3762/bjnano.5.94

• understanding of materials behavior during contact. Mechanical properties of interest comprise hardness, Young’s modulus of elasticity, bulk modulus, elastic–plastic deformation, scratch resistance, residual stresses, time-dependent creep and relaxation properties, fracture toughness, fatigue and yield strength

• mechanical properties such as hardness and Young’s modulus of elasticity can be directly obtained as a function of depth. This can be done with a high degree of accuracy, not easily obtained with an AFM. This advancement in technology has proven useful for understanding the mechanical behavior of micro- and

• the elastic modulus. By using this method the Young’s modulus of elasticity and Poisson’s ratio for diamond were taken as 1140 GPa and 0.07, respectively. Poisson’s ratio for Au was taken as 0.42. The data from these experiments is the average of five measurements on five different nanoparticles for

Analytical development and optimization of a graphene–solution interface capacitance model

• Hediyeh Karimi,
• Rasoul Rahmani,
• Reza Mashayekhi,
• Leyla Ranjbari,
• Amir H. Shirdel,
• Niloofar Haghighian,
• Parisa Movahedi,
• Moein Hadiyan and
• Razali Ismail

Beilstein J. Nanotechnol. 2014, 5, 603–609, doi:10.3762/bjnano.5.71

• can satisfy the major requirements of a channel in electrolyte-gated transistor (EGFET) devices due to its ballistic transport, high conductivity, and strong mechanical and elasticity properties. An analytical modeling of the graphene capacitance as a major characteristic of EGFET is studied in this

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

• cell mechanics, in particular elasticity, and cancer [5][6]. The first measurements showed that cancerous human bladder cells were softer than non-malignant bladder cells. Further measurements of cancerous cells have confirmed that a lowering of the elastic modulus of the cells is a general feature of

• kPa at 500 nm. The decrease of the Young’s modulus with δ has been previously reported [18] although this effect is still not fully understood [5][18][19]. Effect of cytochalasin D on the elasticity of the cells In order to verify the influence of the actin filaments and their structure on Ecell, some

• overall cell elasticity [16][33]. The correlation between the reduction of the Young’s modulus and the depolymerization of the actin filaments supports a predominant role of these filaments on the stiffness of the cells. In order to verify how the organization of the actin cytoskeleton influences the

Single-asperity contact mechanics with positive and negative work of adhesion: Influence of finite-range interactions and a continuum description for the squeeze-out of wetting fluids

• Martin H. Müser

Beilstein J. Nanotechnol. 2014, 5, 419–437, doi:10.3762/bjnano.5.50

• contributions to the linear elasticity of (frictionless) single-asperity contacts most central to this work are the following: Hertz [4] solved the contact mechanics of a parabolic tip pressed against a substrate for hard-wall repulsion. He found that the contact area Ac and the separation between the two

• inspection of Figure 19a. At small loads, the sensitivity of the gap profile on the details of the model become even more apparent. This result, which can be seen in Figure 19c, is expected, since the elasticity of the tip is no longer relevant. Instead, the force-displacement curve is predominantly

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

• away from each other. At P2, the rupture length is similar to that at P3. The distribution is slightly wider, which is possibly the result of the tip picking up the underlying fibril at P2. In addition to rupture force and rupture length, other information, such as the molecular elasticity, can be

Challenges and complexities of multifrequency atomic force microscopy in liquid environments

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 298–307, doi:10.3762/bjnano.5.33

• multiple tip–sample impacts for every cycle of the fundamental eigenmode (c). The simulation parameters are ν1 = 14.5 kHz, k1 = 0.03 N/m, Q1 = 2, Q2 = 6, Afree = 75 nm, Asetpoint = 55% and sample modulus of elasticity of 2 GPa (Hertzian contact). Bimodal AFM simulation illustrating the phase and amplitude

The role of surface corrugation and tip oscillation in single-molecule manipulation with a non-contact atomic force microscope

• Christian Wagner,
• Norman Fournier,
• F. Stefan Tautz and
• Ruslan Temirov

Beilstein J. Nanotechnol. 2014, 5, 202–209, doi:10.3762/bjnano.5.22

• tip elasticity, and the tip oscillation amplitude. In short, we simulate a full tip oscillation cycle at each step of the manipulation process and calculate the frequency shift by solving the equation of motion of the tip. The new model correctly reproduces previously unexplained key features of the

• main factors that have been omitted from the initial model: i) the atomic corrugation of the surface, ii) the elasticity of the tip material, and iii) the finite amplitude of the qPlus tuning fork oscillation. Here we take a step towards more realistic force-field simulations of single-molecule

• corrugation affects ∂Fz/∂z(z) curves measured with NC-AFM can be understood by considering the model of an elastically stretchable (and compressible) rod lifted from a corrugated surface. The model consists of two connected springs, one of which mimics the elasticity of the rod, while the other accounts for

Manipulation of nanoparticles of different shapes inside a scanning electron microscope

• Boris Polyakov,
• Sergei Vlassov,
• Leonid M. Dorogin,
• Jelena Butikova,
• Mikk Antsov,
• Sven Oras,
• Rünno Lõhmus and
• Ilmar Kink

Beilstein J. Nanotechnol. 2014, 5, 133–140, doi:10.3762/bjnano.5.13

• of the contact: where Θ is the contact angle for Ag/SiO2 interface. As described previously [20], for sphere-like NPs contact mechanics (adhesive contact approach) must be applied. The contact area is typically calculated on the basis of continuum elasticity models for deformable spheres such as the

Static analysis of rectangular nanoplates using trigonometric shear deformation theory based on nonlocal elasticity theory

• Mohammad Rahim Nami and
• Maziar Janghorban

Beilstein J. Nanotechnol. 2013, 4, 968–973, doi:10.3762/bjnano.4.109

• , the nonlocal elasticity theory is used. An analytical method is adopted to solve the governing equations for static analysis of simply supported nanoplates. In the present theory, the transverse shear stresses satisfy the traction free boundary conditions of the rectangular plates and these stresses

• isotropic, orthotropic and anisotropic nanoplates. Keywords: nonlocal elasticity theory; rectangular nanoplate; static analysis; trigonometric shear deformation theory; Introduction In recent years, some new higher-order shear deformation theories have been adopted for studying macro structures such as

• deformation theory. The above mentioned methodology could be used for both thick and thin rectangular plates similar to 3D elasticity theory. In this theory, the transverse shear stresses satisfied the traction free boundary conditions of the rectangular plates and these stresses could be calculated from the

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

• the factors discussed in previous reviews over the past decade are still issues today [48][49][50][51]. Most notable of these are the implicit assumptions of linear elasticity, which require the contact radius and the indentation depth to be much smaller than the indenter radius, and the absence of

Size-dependent characteristics of electrostatically actuated fluid-conveying carbon nanotubes based on modified couple stress theory

• Mir Masoud Seyyed Fakhrabadi,
• Abbas Rastgoo and
• Mohammad Taghi Ahmadian

Beilstein J. Nanotechnol. 2013, 4, 771–780, doi:10.3762/bjnano.4.88

• dynamics, it is rarely applied in scrutinizing NEMS because of their limitation in analyzing the complicated behaviors of such systems [9][10][11][12]. Hence, continuum modeling is more frequent and is also applied in this paper. The elasticity equations, which govern the mechanical behaviors on the micro

• between the electrodes lead to deflection of the CNT towards the ground plate (state 2 in Figure 1). The deflection value, w = w(x), corresponds to the applied voltage up to the point at which the elasticity of the CNT can no longer compensate the forces that result from the applied voltage and the

• boundary conditions, the axial force is a compressive force because the clamped ends transform the axial force into a compression. According to the concepts of elasticity and vibration of continuous systems, the tensile force increases the natural frequency and buckling loads of the nanobeam, here the CNT

Routes to rupture and folding of graphene on rough 6H-SiC(0001) and their identification

• M. Temmen,
• O. Ochedowski,
• B. Kleine Bussmann,
• M. Schleberger,
• M. Reichling and
• T. R. J. Bollmann

Beilstein J. Nanotechnol. 2013, 4, 625–631, doi:10.3762/bjnano.4.69

• shown to have unique properties such as high mechanical strength and elasticity, a very high electrical and thermal conductivity, the impermeability to gases, and many others [2]. All of them make it highly attractive for numerous applications, and a most promising candidate for advanced

• flake edges. As can be seen from the comparison of Figure 7a and Figure 7b, the post-preparation treatment of a SLG sheet, which has been folded, can be interpreted as peeling the folding away from the region already opened by the SHI impact as illustrated in Figure 7d [44]. Due to the high elasticity

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

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

• elasticity in this simulation is 2 GPa. The force curve was simulated as the sum of a conservative Hamaker–Hertzian contact with a height-dependent viscous term [14] (this combination of models does not consider surface depression or recovery, so the location of the force minima is the same for the tip

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

• methods that can be used for estimating the stiffness of qPlus sensors. The first method is based on continuum theory of elasticity. The second (Cleveland’s method) uses the change in the eigenfrequency that is induced by the loading of small masses. Finally, the stiffness is obtained by analysis of the

• . The aim of this paper is to compare and critically discuss the following methods for estimating the stiffness of qPlus sensors: (i) the added-mass method; (ii) thermal excitation; and (iii) a method based on the continuum theory of elasticity. In particular we will estimate and compare the stiffness

• value corresponding to the total length. Stiffness calculation from continuum theory of elasticity The tuning fork can be considered as a pure prism with a rectangular cross section. Therefore the stiffness of the tuning fork can be expressed by using the continuum theory of elasticity [31] as follows

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

• number of polymer deposition steps n. The film thickness was determined by two independent AFM-based methods: scratch-and-scan and newly developed full-indentation. The advantages and disadvantages of both methods are highlighted, and error minimization techniques in elasticity measurements are addressed

• , which is highly sensitive to the elasticity of the substrate, must be known and controlled for the development of contact lenses and antifouling materials [3][5][6]. Nevertheless, thin films have to be studied in the form in which they are available, making the use of macroscopic methods unsuitable

• hydrogel particles [19][20][21][22]. Recent advances in the area have been summarized by Picart and co-workers [23][24]. Several studies on the bio-applicability of polymer-based films showed that if cells are deposited on a surface with an elasticity gradient, they move from the softer region to a

Probing three-dimensional surface force fields with atomic resolution: Measurement strategies, limitations, and artifact reduction

• Mehmet Z. Baykara,
• Omur E. Dagdeviren,
• Todd C. Schwendemann,
• Harry Mönig,
• Eric I. Altman and
• Udo D. Schwarz

Beilstein J. Nanotechnol. 2012, 3, 637–650, doi:10.3762/bjnano.3.73

• spectroscopy; NC-AFM; three-dimensional atomic force microscopy; tip asymmetry; tip elasticity; Introduction Experimentally obtained information about atomic-scale interactions of specific surfaces with atoms, molecules, and other surfaces in their vicinity is crucial for a number of important scientific

• well-characterized tips on the ionic surface of NaCl(001) have been shown to unambiguously coincide with surface anions, facilitating atomic-scale chemical identification. Tip elasticity In addition to drift and piezo effects, the accuracy with which a numerical value, obtained through two- or three

• ), respectively, in which shifts of characteristic maxima in atomic-scale images and significant distortions of the observed contrast patterns attributed to tip apex elasticity were observed as a function of tip–sample distance. On our path towards finding strategies that reduce the impact of tip deformation on

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

• = 1 N/m, R = 30 nm, and z0 = 2 nm, while 0.1 GPa and 1 GPa were assigned to E*. FMM measurements are less nonlinear at (i) high contact forces and (ii) for stiff materials, as shown by the lower amplitude ratio in these cases in Figure 1. This implies that changes in the surface elasticity can lead to

• determines the interaction force from which the contact stiffness can be calculated (Equation 2). The amplitude of the first harmonic is used to analyze the elasticity of the substrate surface in FMM and it is thus essential to relate the first harmonic with the contact stiffness experimentally. Meanwhile