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

• recent review [13]. The mechanical properties of amyloid materials have also been characterised through various biophysical techniques [14]. These include the use of atomic force microscopy (AFM), and in particular, AFM nanoindentation methods to deduce the elastic properties of amyloid [15][16][17][18

Effect of normal load and roughness on the nanoscale friction coefficient in the elastic and plastic contact regime

• Aditya Kumar,
• Thorsten Staedler and
• Xin Jiang

Beilstein J. Nanotechnol. 2013, 4, 66–71, doi:10.3762/bjnano.4.7

• during nanoindentation-based scratching has been experimentally investigated by using different surfaces (fused silica and diamond-like carbon) featuring various degrees of roughness. At a sufficiently low applied normal load, wherein the contact is elastic, the friction coefficient is constant. However

• indenter and decreases with roughness. Distinct differences between the present experimental results and the existing theoretical models/predictions are discussed. Keywords: nanoindentation; nanotribology; scratch testing; surface roughness; Introduction Understanding the contact phenomena underlying

• tribological processes is fundamental to many basic and applied problems, such as wetting, capillarity, adhesion, lubrication, sealing, hardness, micro/nanoindentation, atomic-scale probing, surface modification and manipulation [1][2][3]. The contact of two bodies may be defined by the influential parameters

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

• biological processes [3]. In this work, scanning- and colloidal-probe AFM were used to perform nanoindentation on poly (L-lysine)/hyaluronan (PLL/HA)n films with n = 12–96, in order to better understand their growth behaviour, apparent Young’s modulus, and viscoelastic properties. Results and Discussion

Friction and durability of virgin and damaged skin with and without skin cream treatment using atomic force microscopy

• Bharat Bhushan,
• Si Chen and
• Shirong Ge

Beilstein J. Nanotechnol. 2012, 3, 731–746, doi:10.3762/bjnano.3.83

• sample surface and the contact angle was measured. Nanoindentation measurements The nanoindentation measurements were made by using a Hysitron Triboscope (Hysitron Inc., Minneapolis, MN) in the constant displacement rate loading mode with a three-sided pyramidal diamond (Berkovich) tip. In this study

• and the Poisson’s ratio of the indenter tip respectively; ν is the Poisson’s ratio of skin assumed to be 0.5 [6]; Er is the reduced modulus given as follows: where S is the contact stiffness obtained from the slope of the unloading curve. Results and Discussion The nanoindentation properties are

• presented in the first section. Then the surface roughness, contact angle and nano- and macroscale friction data of rat skin are presented. Finally, data of pig skin are presented. Nanoindentation properties of rat and pig skin Mechanical properties of rat and pig skin were measured by using a nanoindenter

Nano-FTIR chemical mapping of minerals in biological materials

• Sergiu Amarie,
• Paul Zaslansky,
• Yusuke Kajihara,
• Erika Griesshaber,
• Wolfgang W. Schmahl and
• Fritz Keilmann

Beilstein J. Nanotechnol. 2012, 3, 312–323, doi:10.3762/bjnano.3.35

• examples of M. edulis and human dentin reveal exquisite detail, which matches what is observed by electron microscopy and nanoindentation. The achievement of chemical and structural mapping of biominerals opens new horizons for our understanding of mineral arrangements and variability in biological systems

Theoretical study of the frequency shift in bimodal FM-AFM by fractional calculus

• Elena T. Herruzo and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2012, 3, 198–206, doi:10.3762/bjnano.3.22

• the sample properties in a quantitative way [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Both static (contact) [2][3][4][5][6][7] and dynamic [8][9][10][11][14][15][16][17] AFM methods have been applied. Static techniques such as nanoindentation [2], pulsed-force mode [3] and force modulation

Direct monitoring of opto-mechanical switching of self-assembled monolayer films containing the azobenzene group

• Einat Tirosh,
• Enrico Benassi,
• Silvio Pipolo,
• Marcel Mayor,
• Michal Valášek,
• Veronica Frydman,
• Stefano Corni and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2011, 2, 834–844, doi:10.3762/bjnano.2.93

• through a facile cis↔trans isomerization that is controlled by UV and visible light. The forces involved in this transition have been characterized by a number of techniques. For instance, changes in the stiffness of azobenzene-containing films were monitored by nanoindentation [1], by quartz-crystal

• the calculated values. Results and Discussion Experimental measurements Measurement of the mechanical properties of monolayer films represents a technological challenge. Nanoindentation is appropriate for direct determination of local stiffness since the measurement is direct and, to first order

• appropriate for organic monolayer systems [16]. Another consideration for nanoindentation measurements is the substrate effect. "Buckle's rule" maintains that in order to gain information on the film only, and not the substrate, the depth of penetration into the film must not exceed 10% of the total film

Infrared receptors in pyrophilous (“fire loving”) insects as model for new un-cooled infrared sensors

• David Klocke,
• Anke Schmitz,
• Helmut Soltner,
• Herbert Bousack and
• Helmut Schmitz

Beilstein J. Nanotechnol. 2011, 2, 186–197, doi:10.3762/bjnano.2.22

• nanoindentation (for details see “Experimental” section). Twenty indents were made in each region. "Ref. Meso": reference mesocuticle outside of IR receptor. Principle of a gas-filled Golay sensor with optical read-out. For explanations see text. Comparison of the sensillum (left) with the model of the sensor