Bio-inspired micro-to-nanoporous polymers with tunable stiffness

• Julia Syurik,
• Ruth Schwaiger,
• Prerna Sudera,
• Stephan Weyand,
• Siegbert Johnsen,
• Gabriele Wiegand and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 906–914, doi:10.3762/bjnano.8.92

• fabricated and investigated by dynamic flat-punch nanoindentation in order to obtain insight into the influence of the graded pore structure on the local viscoelastic properties. Experimental Materials and foaming process Porous poly(methyl methacrylate) (PMMA) films were produced from PMMA (Topacryl AG

• equal to 3. Preparation of cross sections The porous PMMA films were fractured perpendicular to the surface in the middle of the sample. In order to obtain a surface of sufficient quality for nanoindentation testing, the samples were cooled with liquid nitrogen for 180 s, then broken with tweezers

• , fixed within a holder for nanoindentation and finally trimmed with a microtome (Leica Ultracut UCT). The areas suitable for nanoindentation experiments were determined from SEM images (see below in Figure 2a). Nanoindentation For the current study, two porous PMMA samples exhibiting a structural

Annealing-induced recovery of indents in thin Au(Fe) bilayer films

• Anna Kosinova,
• Ruth Schwaiger,
• Leonid Klinger and
• Eugen Rabkin

Beilstein J. Nanotechnol. 2016, 7, 2088–2099, doi:10.3762/bjnano.7.199

• Abstract We employed depth-sensing nanoindentation to produce ordered arrays of indents on the surface of 50 nm-thick Au(Fe) films deposited on sapphire substrates. The maximum depth of the indents was approximately one-half of the film thickness. The indented films were annealed at a temperature of 700 °C

• traditional methods of high-strain deformation, such as rolling or forging, are not applicable. Nanoindentation is widely used for characterizing the mechanical properties of nano- and micro-scale specimens. It can also be employed to produce defects of controlled shape and size, and to introduce high plastic

• introduced by nanoindentation with subsequent annealing, and (ii) to understand the effect of nanoindentation-induced localized plastic deformation on the thermal stability and solid-state dewetting of thin films. In what follows, we will give a short overview of what is known about the recovery of indents

Nanoanalytics for materials science

• Thilo Glatzel and
• Tom Wirtz

Beilstein J. Nanotechnol. 2016, 7, 1674–1675, doi:10.3762/bjnano.7.159

• sensors for both nanoindentation and depth sensing is presented by Cinar and co-workers [2]. Furthermore, Fleming et al. present an in situ combination of atomic force microscopy (AFM) and secondary ion mass spectrometry (SIMS) [3]. By doing so, they obtain high-resolution 3D elemental/chemical maps. This

Deformation-driven catalysis of nanocrystallization in amorphous Al alloys

• Rainer J. Hebert,
• John H. Perepezko,
• Harald Rösner and
• Gerhard Wilde

Beilstein J. Nanotechnol. 2016, 7, 1428–1433, doi:10.3762/bjnano.7.134

• ], ball milling [14][15][16][24], cold rolling [12][25][26][27][28][29][30][31][32], high-pressure torsion straining [18][33], nanoindentation [34], and uniaxial compression [35]. The results of intense deformation have demonstrated nanocrystals with number densities of up to 1022 m−3 and average sizes of

Fracture behaviors of pre-cracked monolayer molybdenum disulfide: A molecular dynamics study

• Qi-lin Xiong,
• Zhen-huan Li and
• Xiao-geng Tian

Beilstein J. Nanotechnol. 2016, 7, 1411–1420, doi:10.3762/bjnano.7.132

• on mechanical properties of single-layer MoS2 by adopting MD nanoindentation simulation and found that with the increase of temperature (4.2 K to 500 K), the Young’s moduli, fracture stress and strain of MoS2 decrease and they also studied the tension-induced phase transition of single-layer MoS2 at

Generalized Hertz model for bimodal nanomechanical mapping

• Aleksander Labuda,
• Marta Kocuń,
• Waiman Meinhold,
• Deron Walters and
• Roger Proksch

Beilstein J. Nanotechnol. 2016, 7, 970–982, doi:10.3762/bjnano.7.89

• nanoindentation [27] and force curves as well as dynamic force curves performed with an oscillated cantilever. The time-varying cantilever response serves as input to a model for extracting nanomechanical properties of the sample at any location. These techniques are by nature slow for imaging, as they measure

Determination of Young’s modulus of Sb₂S₃ nanowires by in situ resonance and bending methods

• Liga Jasulaneca,
• Raimonds Meija,
• Alexander I. Livshits,
• Juris Prikulis,
• Subhajit Biswas,
• Justin D. Holmes and
• Donats Erts

Beilstein J. Nanotechnol. 2016, 7, 278–283, doi:10.3762/bjnano.7.25

• test [21][22] and nanoindentation [23]. In situ techniques stand out among other methods for mechanical characterization due to their capability of real-time monitoring of the elastic response of the NWs. Bending tests with a use of external force sensor [24], tensile deformation [25][26] as well as

Fabrication of hybrid nanocomposite scaffolds by incorporating ligand-free hydroxyapatite nanoparticles into biodegradable polymer scaffolds and release studies

• Balazs Farkas,
• Marina Rodio,
• Ilaria Romano,
• Alberto Diaspro,
• Romuald Intartaglia and
• Szabolcs Beke

Beilstein J. Nanotechnol. 2015, 6, 2217–2223, doi:10.3762/bjnano.6.227

• and mechanical properties of the fabricated hybrid thin film was performed by means of SEM and nanoindentation, respectively, while the chemical and degradation studies were conducted through thermogravimetric analysis, and FTIR. The photocuring efficiency was found to be dependent on the nanoparticle

• into biodegradable polymer resin. We also present HA NPs release studies. Results and Discussion Materials characterization In order to evaluate the effects of nanoparticle incorporation, the cured resins have been characterized through nanoindentation, thermogravimetric analysis (TGA), profilometry

• nanoindentation (Figure 2b) measurements show that the stiffness of the fabricated samples can be considered identical, independent of the concentration of the nanoparticles, as well as the laser parameters. Also, the samples (samples 1–6) fabricated with three different HA concentrations (50, 100 and 300 ppm

Development of a novel nanoindentation technique by utilizing a dual-probe AFM system

• Eyup Cinar,
• Ferat Sahin and
• Dalia Yablon

Beilstein J. Nanotechnol. 2015, 6, 2015–2027, doi:10.3762/bjnano.6.205

• nanoindentation is described that exhibits improved resolution and depth sensing. The approach is based on a multi-probe scanning probe microscopy (SPM) tool that utilizes tuning-fork based probes for both indentation and depth sensing. Unlike nanoindentation experiments performed with conventional AFM systems

• for AFM scanning to obtain an accurate profiling. Nanoindentation results are demonstrated on silicon, fused silica, and Corning Eagle Glass. The results show that this new approach is viable in terms of accurately characterizing mechanical properties of materials through nanoindentation with high

• accuracy, and it opens doors to many other exciting applications in the field of nanomechanical characterization. Keywords: atomic force microscopy (AFM); mechanical characterization; nanoindentation; Introduction Nanoindentation is a commonly used technique to estimate mechanical properties of materials

A simple method for the determination of qPlus sensor spring constants

• John Melcher,
• Julian Stirling and
• Gordon A. Shaw

Beilstein J. Nanotechnol. 2015, 6, 1733–1742, doi:10.3762/bjnano.6.177

• limit the tip height to approximately less than 400 μm. Mechanical characterization of qPlus sensors with nanoindentation In this section we characterize the flexural mechanics of qPlus sensors using a nanoindentation method. The nanoindenter, which is calibrated with traceability to the International

• other hand, the nanoindentation experiments presented here are highly reproducible and demonstrate excellent agreement with the theoretical model. There is, however, some potential for further work examining the effect of the mounting on the qPlus spring constant. We have observed a small variation

• μm. A quasi-static nanoindentation method is used to validate Bernoulli–Euler beam theory with fixed-free boundary conditions for modeling the flexure of the tuning fork tine. Indentation data provides the effective length, flexural rigidity, and nominal spring constant of the tine with an estimated

Lower nanometer-scale size limit for the deformation of a metallic glass by shear transformations revealed by quantitative AFM indentation

• Arnaud Caron and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2015, 6, 1721–1732, doi:10.3762/bjnano.6.176

• the projected area of the remaining indent is evaluated by optical microscopy and hardness measurements are limited to the macro-scale. With the development of depth-sensing indentation techniques such as instrumented nanoindentation, the recording of load–displacement curves has been recognized as a

• explains why in this work the hardness was calculated as the slope dAp/dPmax. For Pt(111) we obtained H = 1.14 ± 0.09 GPa; a slightly higher value than HNI = 0.73 GPa which we found from nanoindentation measurements. For Pt57.5Cu14.7Ni5.3P22.5 metallic glass we obtained H = 7.3 ± 2.4 GPa, also larger than

• HNI = 4.11 GPa found from nanoindentation measurements. The larger hardness values based on nc-AFM imaging are attributed to the underestimation of the projected area of indents due to tip convolution. The corresponding error for the metallic glass is larger due to the increased difficulty to

Mandibular gnathobases of marine planktonic copepods – feeding tools with complex micro- and nanoscale composite architectures

• Jan Michels and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2015, 6, 674–685, doi:10.3762/bjnano.6.68

• included in the siliceous teeth of the copepods after moulting. Up to now the mechanical stability of the silica-containing structures of gnathobase teeth has not been analysed. Such an analysis could potentially be performed using nanoindentation. However, because of the small dimensions of the structures

Oxygen-plasma-modified biomimetic nanofibrous scaffolds for enhanced compatibility of cardiovascular implants

• Anna Maria Pappa,
• Varvara Karagkiozaki,
• Silke Krol,
• Spyros Kassavetis,
• Dimitris Konstantinou,
• Charalampos Pitsalidis,
• Lazaros Tzounis,
• Nikos Pliatsikas and
• Stergios Logothetidis

Beilstein J. Nanotechnol. 2015, 6, 254–262, doi:10.3762/bjnano.6.24

• . Goniometry (contact angle measurements), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate the morphological and chemical changes induced by the plasma treatment. Moreover, depth-sensing nanoindentation was

• may lead to improved surface properties without affecting the morphology or the mechanical behaviour of the system. In depth nanoindentation measurements were conducted for the scaffolds under optimal conditions to assess the mechanical performance. MTT assay along with imaging techniques were used to

• further confirm this assumption nanomechanical measurements were conducted, in both mildly treated and untreated systems, and the obtained results were compared. The effect of the O2-plasma treatment on the mechanical properties of the PCL scaffold was studied by using dynamic nanoindentation. In Figure 3

Multifunctional layered magnetic composites

• Maria Siglreitmeier,
• Baohu Wu,
• Tina Kollmann,
• Martin Neubauer,
• Gergely Nagy,
• Dietmar Schwahn,
• Vitaliy Pipich,
• Damien Faivre,
• Dirk Zahn,
• Andreas Fery and
• Helmut Cölfen

Beilstein J. Nanotechnol. 2015, 6, 134–148, doi:10.3762/bjnano.6.13

• superior mechanical performance. Nanoindentation testing with AFM colloidal probe is a powerful technique as it combines high lateral and force resolution with well-defined contact geometry. It has successfully been applied to a range of systems including capsules [49][50][51][52], full particles [53][54

Mechanical properties of sol–gel derived SiO₂ nanotubes

• Boris Polyakov,
• Mikk Antsov,
• Sergei Vlassov,
• Leonid M Dorogin,
• Mikk Vahtrus,
• Roberts Zabels,
• Sven Lange and
• Rünno Lõhmus

Beilstein J. Nanotechnol. 2014, 5, 1808–1814, doi:10.3762/bjnano.5.191

• measured by using different methods. In situ scanning electron microscopy (SEM) cantilever beam bending tests were carried out by using a nanomanipulator equipped with a force sensor in order to investigate plasticity and flexural response of NTs. Nanoindentation and three point bending tests of NTs were

• performed by atomic force microscopy (AFM) under ambient conditions. Half-suspended and three-point bending tests were processed in the framework of linear elasticity theory. Finite element method simulations were used to extract Young’s modulus values from the nanoindentation data. Finally, the Young’s

• of the experimental technique on the measured values of the Young’s modulus was demonstrated by Rohlig et al. for ZnO NWs by comparing the resonant technique, nanoindentation, bending of bridges, and tensile and compressive strain tests [16]. In the case of SiO2 NTs it is also important to consider

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

• (XRF) measurements. Nanoindentation gives insight on the mechanical properties of the films. Organic precursors employed in MLD Both ALD and MLD set some requirements for the precursors employed, such as sufficient vapor pressure, reactivity and stability at the reaction temperature, to ensure feasible

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

• 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

• that mechanical properties are enhanced at smaller scales. Experimental studies that directly compare local with global deformation are lacking. In this research, spherical Au nanoparticles, 500 nm in diameter and 100 nm thick Au films were selected. Nanoindentation (local deformation) and compression

• tests (global deformation) were performed with a nanoindenter using a sharp Berkovich tip and a flat punch, respectively. Data from nanoindentation studies were compared with bulk to study scale effects. Nanoscale hardness of the film was found to be higher than the nanoparticles with both being higher

• than bulk. Both nanoparticles and film showed increasing hardness for decreasing penetration depth. For the film, creep and strain rate effects were observed. In comparison of nanoindentation and compression tests, more pop-ins during loading were observed during the nanoindentation of nanoparticles

Biocalcite, a multifunctional inorganic polymer: Building block for calcareous sponge spicules and bioseed for the synthesis of calcium phosphate-based bone

• Xiaohong Wang,
• Heinz C. Schröder and
• Werner E. G. Müller

Beilstein J. Nanotechnol. 2014, 5, 610–621, doi:10.3762/bjnano.5.72

• acid (Asp, D) and glutamic acid (Glu, E) [50]. The hardness, elastic modulus and creep of the two forms of the calcium carbonate deposits, the calcitic prisms and the round-shaped vaterite deposits were determined by nanoindentation. The load–displacement curves obtained for the two calcium carbonate

Exploring the retention properties of CaF₂ nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid

• Matthias Wasem,
• Joachim Köser,
• Sylvia Hess,
• Enrico Gnecco and
• Ernst Meyer

Beilstein J. Nanotechnol. 2014, 5, 36–43, doi:10.3762/bjnano.5.4

• and caries disease. The use of CaF2 nanoparticles as a source of fluoride in order to prevent caries was already discussed in early studies [19][21][22]. Little research to explore tooth enamel has been done with AFM. Studies investigated the erosion of enamel with AFM based nanoindentation and

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

• important phenomenon that drives material response at different scales of time and space. Burgeoning interest in nanoscale dynamic material mechanics has driven, and been driven by two key techniques: instrumented nanoindentation and atomic force microscopy. This review provides an overview of fundamental

• 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

• limited to, optical tweezers [1], surface force apparatus [2][3], nanomanipulators [4], electron and other microscopy techniques. Two techniques which have made great advances in the studies of nanomechanics are instrumented nanoindentation and scanning probe microscopy. The versatility and utility of

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