Material discrimination and mixture ratio estimation in nanocomposites via harmonic atomic force microscopy

• Weijie Zhang,
• Yuhang Chen,
• Xicheng Xia and
• Jiaru Chu

Beilstein J. Nanotechnol. 2017, 8, 2771–2780, doi:10.3762/bjnano.8.276

• conclusions can be drawn from direct observation. First, higher harmonic amplitudes appear on the PS domain (brighter area), which has a higher elastic modulus. Second, the amplitude difference between PS and LDPE first increases and then decreases when decreasing the set-point within the experimental range

• verify that the harmonic response depends on the contact time and peak contact force. Both quantities are related to the elasticity of the sample. Because the elastic modulus of PS is larger than that of LDPE, oscillating on the PS domain produces a much shorter contact time and a larger peak force in

• value. However, at a higher drive frequency, the amplitude difference becomes positive. The results clearly demonstrate the presence of contrast reversal, which may cause difficulty in further establishment of the quantitative relation between harmonic amplitude and local elastic modulus. To realize

Fabrication of gold-coated PDMS surfaces with arrayed triangular micro/nanopyramids for use as SERS substrates

• Jingran Zhang,
• Yongda Yan,
• Peng Miao and
• Jianxiong Cai

Beilstein J. Nanotechnol. 2017, 8, 2271–2282, doi:10.3762/bjnano.8.227

• mechanical properties such as hardness, elastic modulus and friction coefficient. The fabrication of micro/nanostructures using the nanoindenter method can be also achieved. The shortcomings of this technique include low machining speed, small machining area and high cost, and thus the nanoindentation method

Nanotribological behavior of deep cryogenically treated martensitic stainless steel

• Germán Prieto,
• Konstantinos D. Bakoglidis,
• Walter R. Tuckart and
• Esteban Broitman

Beilstein J. Nanotechnol. 2017, 8, 1760–1768, doi:10.3762/bjnano.8.177

• of calculated hardness and elastic modulus from their real values. The formation of pile-ups during nanoindentation of steels has been studied by several researchers [29][30][31]. Our approach was to compare the conventional O&P method with the one proposed by Joslin and Oliver (J&O) [32]. The J&O

• method utilizes the ratio between the hardness and the square of the elastic modulus (H/E2) as an independent characteristic parameter. The proposed method utilizes the maximum force applied during the test (P) and the calculated contact stiffness (S) from the nanoindentation data. S is defined as the

• relative elastic modulus, defined as Es and νs are Young’s modulus and Poisson’s ratio of the sample, and Ei and νi are Young’s modulus and Poisson’s ratio of the indenter (Ei = 1140 GPa, νi = 0.07). This approach does not allow for the simultaneous determination of E and H, but several researchers [33][34

Oxidative stabilization of polyacrylonitrile nanofibers and carbon nanofibers containing graphene oxide (GO): a spectroscopic and electrochemical study

• İlknur Gergin,
• Ezgi Ismar and
• A. Sezai Sarac

Beilstein J. Nanotechnol. 2017, 8, 1616–1628, doi:10.3762/bjnano.8.161

• properties in terms of modulus. Figure 2 shows stress–strain plots of aligned and non-aligned PAN nanofibers. According to the plots, the elastic modulus of a PAN-nanofiber web increases with fiber orientation from 63 MPa to 159 MPa. Thus, rotating collectors were chosen to obtain nanofibers with better

Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications

• Suneel Kumar,
• Ashish Kumar,
• Ashish Bahuguna,
• Vipul Sharma and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2017, 8, 1571–1600, doi:10.3762/bjnano.8.159

• high transparency, high elastic modulus (≈1 TPa), high mechanical strength (≈1060 GPa), and optical transmittance (≈97.7%) [44]. These superior properties of graphene make it a potential candidate for technological application such as such as optical electronics [45], photosensors [46] and

Luminescent supramolecular hydrogels from a tripeptide and nitrogen-doped carbon nanodots

• Maria C. Cringoli,
• Slavko Kralj,
• Marina Kurbasic,
• Massimo Urban and
• Silvia Marchesan

Beilstein J. Nanotechnol. 2017, 8, 1553–1562, doi:10.3762/bjnano.8.157

• so rapid that the monitoring of the sol-to-gel transition was not possible. Time sweep experiments (Figure 2a,c,e) revealed that relative to the peptide alone, which reached an elastic modulus G’ of 20 kPa within 1 h (Figure 2a), the addition of NCNDs to the peptide prior to self-assembly (Figure 2c

• hydrogel had already reached an elastic modulus of 10 kPa, thus yielding a stiffer material relative to the former case (Figure 2e). In any case, at any given time point, the hydrogels containing NCNDs displayed a lower elastic modulus G’ relative to the peptide alone. This phenomenon could be compatible

Parylene C as a versatile dielectric material for organic field-effect transistors

• Tomasz Marszalek,
• Maciej Gazicki-Lipman and
• Jacek Ulanski

Beilstein J. Nanotechnol. 2017, 8, 1532–1545, doi:10.3762/bjnano.8.155

• crystallinity of Parylene C films affects their mechanical properties such as elastic modulus and/or Poisson’s ratio. The sample with higher crystallinity has approximately 30% greater tensile strength than the as-deposited films, a feature highly required from the point of view of material flexibility. The

Nanotopographical control of surfaces using chemical vapor deposition processes

• Meike Koenig and
• Joerg Lahann

Beilstein J. Nanotechnol. 2017, 8, 1250–1256, doi:10.3762/bjnano.8.126

• the elastic modulus of the polymer coating and the substrate. Haller et al. investigated the morphology of vapor-deposited polymers on liquid substrates (Figure 3) [29]. Depending on surface tension, liquid viscosity, deposition rate and deposition time, either film or particle formation was found

Assembly of metallic nanoparticle arrays on glass via nanoimprinting and thin-film dewetting

• Sun-Kyu Lee,
• Sori Hwang,
• Yoon-Kee Kim and
• Yong-Jun Oh

Beilstein J. Nanotechnol. 2017, 8, 1049–1055, doi:10.3762/bjnano.8.106

• , nanoindentation measurements were conducted. The measurements were performed using a nanoindentation system (MTS Nano-indenter XP) equipped with continuous stiffness measurement using a Berkovich indenter, and the elastic modulus and nanohardness were calculated using the method of Oliver and Pharr [32]. The

• examine the effect of the annealing temperatures on the mechanical stability of the structure, nanoindentation measurements were conducted for the resists on glass annealed at ≈400–600 °C. Figure 4a,b shows the changes in the composite hardness and elastic modulus of the thin resist–glass substrate as a

• annealed at different temperatures: (a) hardness and (b) elastic modulus. Photograph of transparent glass with Ag nanoparticle arrays. Metal nanoparticles formed on imprinted sol–gel silica: (a,b) 8 nm thick and (c,d) 10 nm thick Ag films dewetted at 300 °C, (e,f) 14 nm thick Ag and (g,h) Au films dewetted

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

• polymeric foams have a lower density than the respective monolithic bulk material and, thus, typically exhibit a reduced elastic modulus [14]. Microporous polymers have been under development since the 1960s [15][16]. The development of fabrication methods allowing for smaller pore sizes made the next

• properties of a material with a pore-size gradient, have not been demonstrated yet. For nanocellular polymers, for example, two opposite effects were predicted: (i) local hardening of the material due to material confinement on nanometre dimensions [21] and (ii) a great reduction of elastic modulus of thin

• demonstrate that a foam of a stiff polymer such as poly(methyl methacrylate) (PMMA) can exhibit a gradually changing effective elastic modulus when the local morphology of the sample undergoes a transition from microcellular to nanocellular. Porous PMMA films with a controlled gradient of the pore size were

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

• Gheorghe Stan,
• Richard S. Gates,
• Qichi Hu,
• Kevin Kjoller,
• Craig Prater,
• Kanwal Jit Singh,
• Ebony Mays and
• Sean W. King

Beilstein J. Nanotechnol. 2017, 8, 863–871, doi:10.3762/bjnano.8.88

• ., elastic modulus) of the samples are resolved. The spatial resolution of CR-AFM is determined by the contact radius established during measurements and it can be as small as 5–10 nm [33]. For the AFM-IR measurements presented here, a nanoIR2™ instrument was utilized. This instrument was equipped with a

• , Bruker, Santa Barbara, CA) at the oscillation frequency. For each measurement, the tip was brought into contact at a setpoint of 60 nN applied force and the frequency of the imposed modulation was swept from 100 kHz to 1 MHz with a step of 250 Hz [33][34]. The elastic modulus calculations were made by

• contribution in this case [42], and a direct comparison with the CR-AFM measurements on the wider fins would therefore be inconsistent. The decrease in SiC–H3 absorbance and increase in the elastic modulus as a function of fin width are summarized in Figure 3. In terms of elastic modulus, the 500 nm and 90 nm

Multimodal cantilevers with novel piezoelectric layer topology for sensitivity enhancement

• Steven Ian Moore,
• Michael G. Ruppert and
• Yuen Kuan Yong

Beilstein J. Nanotechnol. 2017, 8, 358–371, doi:10.3762/bjnano.8.38

• was shown that these higher modes can be more sensitive to material properties such as elastic modulus and damping coefficients [17][18][19]. Additionally, stiff cantilevers have proven to provide high resolution imaging in ambient and liquid environments using quartz resonators [20][21]. Traditional

• aluminium is deposited on the device layer. A particular limitation of this process in the context of AFM is that it does not allow for the fabrication of tips preventing the demonstration of imaging using these cantilevers. The material properties of the silicon used in the analysis are an elastic modulus

When the going gets rough – studying the effect of surface roughness on the adhesive abilities of tree frogs

• Niall Crawford,
• Thomas Endlein,
• Jonathan T. Pham,
• Mathis Riehle and
• W. Jon P. Barnes

Beilstein J. Nanotechnol. 2016, 7, 2116–2131, doi:10.3762/bjnano.7.201

• experiments where the conformation of the pad to individual asperities was examined microscopically, our calculations indicate that the pad epithelium has a low elastic modulus, making it highly deformable. Keywords: adhesion; friction; Litoria caerulea; roughness; tree frog; Introduction Tree frogs exhibit

• difficult. The pads of tree frogs are very soft and so should deform to mould around rough surfaces, as is seen in smooth padded insects [17]. The Young’s modulus of the toe pads has been measured in several studies, an elastic modulus of 40–55 kPa based on AFM indentation being the most recent estimate [18

• ]. Barnes et al. [19] carried out indentations at different depths and measured different degrees of stiffness at different depths, lower values for the elastic modulus resulting from larger indentations. This is probably due to the stiff outer keratinous surface of the pad. The toes also have extensive

The difference in the thermal conductivity of nanofluids measured by different methods and its rationalization

• Aparna Zagabathuni,
• Sudipto Ghosh and
• Shyamal Kumar Pabi

Beilstein J. Nanotechnol. 2016, 7, 2037–2044, doi:10.3762/bjnano.7.194

• can be determined from the impact dynamics [27] as with where rnp is the radius of nanoparticle (Figure 2), vcoll is the nanoparticle velocity, ρ is the nanoparticle density, ω is the elastic parameter for the nanoparticle. The elastic parameter ω is defined by where E is the elastic modulus and µ is

Reasons and remedies for the agglomeration of multilayered graphene and carbon nanotubes in polymers

• Rasheed Atif and
• Fawad Inam

Beilstein J. Nanotechnol. 2016, 7, 1174–1196, doi:10.3762/bjnano.7.109

• matrix to reinforcement. The impact strength and fracture toughness increase significantly while elastic modulus and tensile strength increase marginally with increase in aspect ratio [40]. The transfer of external loads also requires strong interfacial bond. Qian et al. have studied the load transfer

Finite-size effect on the dynamic and sensing performances of graphene resonators: the role of edge stress

• Chang-Wan Kim,
• Mai Duc Dai and
• Kilho Eom

Beilstein J. Nanotechnol. 2016, 7, 685–696, doi:10.3762/bjnano.7.61

• [12][13] properties, which imply that graphene can be used for developing a multifunctional NEMS device. For instance, a monolayer graphene sheet has recently been reported to exhibit a high elastic modulus of the order of 1 TPa [14][15][16], which is much larger than that of conventional engineering

• of 1 MHz to 1 GHz [18][19][20][21]. This high-frequency dynamics of a graphene resonator is ascribed to its remarkable elastic modulus and its low mass density. Here, the resonant frequency of a graphene operating in the harmonic oscillation regime is given by a relation of with E and ρ being the

• elastic modulus and mass density of a graphene, respectively. Since the pioneering work by researchers at Cornell [17], there have recently been efforts to develop the graphene-based resonators for applications in actuation and sensing (e.g., atomic mass detection). The high-frequency dynamic range of

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 surface elastic modulus is zero. Figure 9 compares the shape of the indentation profiles and their relaxation in time for the case of zero surface elastic modulus (Figure 9a) and a 2D surface elastic modulus of 3.1 N/m (Figure 9b). The latter corresponds to approximately 1/120 of the 2D Young’s

• also worth emphasizing the counterintuitive observation that in Figure 8a the force curves corresponding to a larger 2D surface elastic modulus (which Figure 8f indicates lead to shallower indentations) exhibit the largest amount of dissipation (they have hysteresis loops of larger area [14]). This is

• amplitude on the order of 1–2 nm for the parameters considered, which will give a comparable error in the topographical measurement. Interaction between 2D surface elastic modulus and tip geometry One of the most relevant consequences of having different properties at the surface in comparison to the bulk

Free vibration of functionally graded carbon-nanotube-reinforced composite plates with cutout

• Mostafa Mirzaei and
• Yaser Kiani

Beilstein J. Nanotechnol. 2016, 7, 511–523, doi:10.3762/bjnano.7.45

• superscript m. Following the classical solid mechanics notation, E and G are the elastic modulus and shear modulus of the constituents, respectively. In comparison to the conventional rule of mixtures approach, three unknown constants, η1, η2 and η3, are introduced in Equation 1; these are known as efficiency

High-bandwidth multimode self-sensing in bimodal atomic force microscopy

• Michael G. Ruppert and
• S. O. Reza Moheimani

Beilstein J. Nanotechnol. 2016, 7, 284–295, doi:10.3762/bjnano.7.26

• calibration grating available from NT-MDT with periodic rectangular features of heights h = 21.6 ± 1.5 nm and a blend of polystyrene (PS) and polyolefin elastomer (ethylene-octene copolymer) (LDPE) available from Bruker (PS-LDPE-12M). The PS regions of the sample have elastic modulus numbers around 2 GPa

• , while the LDPE regions have elastic modulus numbers around 0.1 GPa making it a widely used standard to image material contrast. The scan speed was set to 20 μm/s at an area of 10 μm × 10 μm. Approach curves Approach and retract curves have been performed on the (stiff) TGZ1 calibration grating where the

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

• models for determining the elastic modulus of cells [2]. In addition to the biomedical engineering field, nanoindentation has been widely used in many other disciplines where accurate mechanical characterization is of high importance [3][4]. The improvement of sensor technology has enabled the

• value of the cantilever. Depending on the type of the material, various models can be applied in order to interpret and extract the elastic modulus of materials. One of the problems with this AFM-based approach is cantilever bending. Most of the conventional AFM nanoindentation probes have spring

• references in the literature. The last section is devoted to the conclusions. Theoretical background on nanoindentation A widely used mechanical model in nanoindentation experiments is the Oliver–Pharr (OP) model [16]. Properties such as elastic modulus or hardness of materials can be extracted from force

Simulation of thermal stress and buckling instability in Si/Ge and Ge/Si core/shell nanowires

• Suvankar Das,
• Amitava Moitra,
• Mishreyee Bhattacharya and
• Amlan Dutta

Beilstein J. Nanotechnol. 2015, 6, 1970–1977, doi:10.3762/bjnano.6.201

• present features that restrict the prediction of the overall elastic modulus through simple analytical means. Decomposing the system into an isolated nanowire (core) and outer tube (shell) to apply the parallel spring model yields incorrect results due to the effect of the core–shell interface [16

• . This behavior can be understood simply by observing the elastic modulus of the monoelemental NWs (represented as 10 nm core diameter). Silicon, being stiffer than germanium, shows a general tendency of an increasing Young’s modulus with a rise in its compositional contribution in the hetrerostructure

• . Interestingly, the crossover between the elastic modulus of Si/Ge and Ge/Si NWs occurs near a core diameter of ≈7 nm. This is a structure with equal volume occupied by the core and shell parts of the material. The next step of our computation involved the estimation of coefficient of thermal expansion (CTE

Atomic force microscopy as analytical tool to study physico-mechanical properties of intestinal cells

• Christa Schimpel,
• Oliver Werzer,
• Eleonore Fröhlich,
• Gerd Leitinger,
• Markus Absenger-Novak,
• Birgit Teubl,
• Andreas Zimmer and
• Eva Roblegg

Beilstein J. Nanotechnol. 2015, 6, 1457–1466, doi:10.3762/bjnano.6.151

• studies [44][45]. It was shown in astrocytes (glial cells) that the elastic modulus near the nuclear region was an order of magnitude higher than at the edge of the cell. However, Caco-2 cells showed a 1.7-fold reduced elasticity compared to M cells (Figure 4A–F). Specifically at regions near the nucleus

Capillary and van der Waals interactions on CaF₂ crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

• Annalisa Calò,
• Oriol Vidal Robles,
• Sergio Santos and
• Albert Verdaguer

Beilstein J. Nanotechnol. 2015, 6, 809–819, doi:10.3762/bjnano.6.84

• (DMT) model of contact mechanics [54] has been employed to account for short range repulsion: where E* is the effective Young’s modulus that includes the elastic modulus of the tip and of the sample [14]. This profile is shown in Figure 4b. 2) The second profile corresponds to a linear decay in the

Mapping of elasticity and damping in an α + β titanium alloy through atomic force acoustic microscopy

• M. Kalyan Phani,
• Anish Kumar,
• T. Jayakumar,
• Walter Arnold and
• Konrad Samwer

Beilstein J. Nanotechnol. 2015, 6, 767–776, doi:10.3762/bjnano.6.79

• successfully mapped the indentation modulus of α- and β-phases in a Ti-6Al-4V alloy by using AFAM while using a cantilever dynamic model in which damping, however, was neglected. In this paper, we report mapping of elastic modulus and damping using a modified cantilever dynamic model in various phases, such as

• moment of inertia. By using an appropriate contact mechanics model, one can convert the obtained stiffness values to the reduced elastic modulus E* and then to the indentation modulus M. The contact mechanics for AFM tips is very difficult to model as the exact shape of the tip in contact with the sample

• * is the reduced elastic modulus, R is the radius of curvature of the cantilever tip and P is the load applied on the specimen through the cantilever. There is one unknown, R, which can be eliminated by using a reference method. Reference material can either be a single crystal with known orientations

Influence of grain size and composition, topology and excess free volume on the deformation behavior of Cu–Zr nanoglasses

• Daniel Şopu and
• Karsten Albe

Beilstein J. Nanotechnol. 2015, 6, 537–545, doi:10.3762/bjnano.6.56

• hardness and a low elastic modulus as compared to their bulk counterparts [8]. In light of these interesting results, further studies on the mechanical properties of this new type of material seem to be mandatory. Critical questions are, if and how mechanical properties of NGs change by varying the grain