Friction reduction through biologically inspired scale-like laser surface textures

• Johannes Schneider,
• Vergil Djamiykov and
• Christian Greiner

Beilstein J. Nanotechnol. 2018, 9, 2561–2572, doi:10.3762/bjnano.9.238

• detrimental effect by introducing a scale-like surface morphology for smaller sliding speeds was observed. Surface profilometry on the discs after the experiments revealed surface roughness values of Ra ≈ 250 nm, demonstrating that the discs became slightly rougher. Occasional signs of adhesive wear events

Evidence of friction reduction in laterally graded materials

• Roberto Guarino,
• Gianluca Costagliola,
• Federico Bosia and
• Nicola Maria Pugno

Beilstein J. Nanotechnol. 2018, 9, 2443–2456, doi:10.3762/bjnano.9.229

• frictional and adhesive behaviour can also be achieved by exploiting a grading of the material properties. In this paper, we investigate this possibility by considering the frictional sliding of elastic surfaces in the presence of a spatial variation of the Young’s modulus and the local friction coefficients

• , display setae with a graded stiffness that optimises the adhesive performance on rough surfaces [1]. Hardness and stiffness gradients are of fundamental importance in the biomechanics of contacts, since they allow increased resistance against wear, impact, penetration and crack propagation [2][3][4][5][6

Droplet-based synthesis of homogeneous magnetic iron oxide nanoparticles

• Christian D. Ahrberg,
• Ji Wook Choi and
• Bong Geun Chung

Beilstein J. Nanotechnol. 2018, 9, 2413–2420, doi:10.3762/bjnano.9.226

• of hot-melt adhesive. The remaining tubing after the junction was submerged in a water bath and the end was placed into a vial filled with water for sample collection. For droplet experiments the formation of droplets was recorded using a bright-field microscope (IX37, Olympus, Japan). Droplet

Adhesive contact of rough brushes

• Qiang Li and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2018, 9, 2405–2412, doi:10.3762/bjnano.9.225

• Qiang Li Valentin L. Popov Berlin University of Technology, 10623 Berlin, Germany National Research Tomsk State University, 634050 Tomsk, Russia National Research Tomsk Polytechnic University, 634050 Tomsk, Russia 10.3762/bjnano.9.225 Abstract The adhesive contact between a rough brush-like

• gecko feet and structured biomimetic materials. For rigid brushes, the contact splitting does not enhance adhesion even if all pillars of the brush are positioned at the same height. Introducing statistical scatter of height leads to a further decrease of the maximum adhesive strength. At the same time

• modification due to finite size effect of the brush. Keywords: adhesion; brushes; contact splitting; pressure sensitive adhesion; roughness; Introduction The study of adhesive contacts has been largely enhanced by studies of the extremely effective adhesion pads of geckos [1]. For example, the adhesion can

Nanoscale characterization of the temporary adhesive of the sea urchin Paracentrotus lividus

• Ana S. Viana and
• Romana Santos

Beilstein J. Nanotechnol. 2018, 9, 2277–2286, doi:10.3762/bjnano.9.212

• , the first nanoscale characterization of sea urchin temporary adhesives was performed using atomic force microscopy (AFM). Results: The adhesive topography was similar under dry and native (seawater) conditions, which was comprised of a honeycomb-like meshwork of aggregated globular nanostructures. In

• terms of adhesion forces, higher values were obtained in dry conditions, reaching up to 50 nN. Under native conditions, lower adhesive forces were obtained (up to 500 pN) but the adhesive seemed to behave like a functional amyloid, as evidenced by the recorded characteristic sawtooth force–extension

• curves and positive thioflavin-T labelling. Conclusion: Our results confirm that like other temporary adhesives, the sea urchin adhesive footprint nanostructure consists of a meshwork of entangled globular nanostructures. Under native conditions, the adhesive footprints of the sea urchin behaved like a

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

The structural and chemical basis of temporary adhesion in the sea star Asterina gibbosa

• Birgit Lengerer,
• Marie Bonneel,
• Mathilde Lefevre,
• Elise Hennebert,
• Philippe Leclère,
• Emmanuel Gosselin,
• Peter Ladurner and
• Patrick Flammang

Beilstein J. Nanotechnol. 2018, 9, 2071–2086, doi:10.3762/bjnano.9.196

• inspiration for biomedical and industrial applications. Nevertheless, natural adhesives and especially temporary adhesion systems are mostly unexplored. Sea stars are able to repeatedly attach and detach their hydraulic tube feet. This ability is based on a duo-gland system and, upon detachment, the adhesive

• morphology of tube feet was described using histological sections, transmission-, and scanning electron microscopy. Ultrastructural investigations revealed two adhesive gland cell types that both form electron-dense secretory granules with a more lucid outer rim and one de-adhesive gland cell type with

• tested 24 commercially available lectins and two antibodies for their ability to label the adhesive epidermis and footprints. Out of 15 lectins labelling structures in the area of the duo-gland adhesive system, only one also labelled footprints indicating the presence of glycoconjugates with α-linked

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• the nanometer scale Molecular layers play an important role in the reduction of friction and wear at the macro scale. The addition of boundary lubricants is necessary to prevent damaging metallic adhesive forces between the machine parts in relative motion (cold welding). Unfortunately, under high

• have shown that electrical fields can be used to change frictional properties by orders of magnitude [179]. Molecular layers can be studied relatively to their frictional, adhesive and elastic properties and how can these mechanical properties be controlled by external means. In the future, we may be

Synthesis of hafnium nanoparticles and hafnium nanoparticle films by gas condensation and energetic deposition

• Irini Michelakaki,
• Nikos Boukos,
• Dimitrios A. Dragatogiannis,
• Spyros Stathopoulos,
• Costas A. Charitidis and
• Dimitris Tsoukalas

Beilstein J. Nanotechnol. 2018, 9, 1868–1880, doi:10.3762/bjnano.9.179

• catalysis [25] to energy storage [26][27]. While an increasing number of applications of porous NTFs are proposed in the literature, the poor mechanical stability of these systems is a major drawback that prevents their widespread industrial use. The weak adhesive force between the nanoparticles leads to

• undergone mechanical reinforcement with other techniques [29][30]. We believe it is porosity and strength of the bonding between the grains that affect the mechanical properties of the films. In the case of Vs = 0 kV, fragile NP coatings with poor mechanical properties are formed due to the weak adhesive

Friction force microscopy of tribochemistry and interfacial ageing for the SiO_x/Si/Au system

• Christiane Petzold,
• Marcus Koch and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2018, 9, 1647–1658, doi:10.3762/bjnano.9.157

• was observed for oxidized silicon tips sliding on Au(111) or on oxidized Si(100) surfaces. We therefore deliberately increased the adhesive forces between probes and surfaces. In an attempt to allow for the successive formation of chemical bonds in contact ageing experiments, we removed passivating

• contact for 48 h until cold welding had occurred and adhesive forces between tip and surface had become larger than the force detection range of the cantilever. We found that the tip was reactive after pulling it off the surface, indicating a partial removal of the Au coating. The friction force was

• Au layer, while no adhesive Cr layer could be distinguished between Si and Au. An amorphous layer (marked with asterisk in Figure 7) with a thickness of about 13 nm covers the surface that had been in sliding contact with Au(111). A rather sharp border marks the transition from amorphous Si to

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• nominally 100 nm thickness is deposited using electron beam evaporation (Intvac Nanochrome I) onto a high quality borosilicate glass slide with 5 nm of chromium as an adhesive layer. The rate of deposition of the gold was set to 0.3 Å/s. High quality azimuthal arrangements of three slot apertures with

Surface characterization of nanoparticles using near-field light scattering

• Eunsoo Yoo,
• Yizhong Liu,
• Chukwuazam A. Nwasike,
• Sebastian R. Freeman,
• Brian C. DiPaolo,
• Bernardo Cordovez and
• Amber L. Doiron

Beilstein J. Nanotechnol. 2018, 9, 1228–1238, doi:10.3762/bjnano.9.114

• Zeiss, Thornwood, NY) with an accelerating voltage of 2 kV. Each dried sample was placed on a metallic pin stub with adhesive and was coated with carbon (Cressington 208C High Vacuum Turbo Carbon Coater, Ted Pella Inc.). Dynamic light scattering and zeta potential The hydrodynamic diameter, size

Electrostatic force spectroscopy revealing the degree of reduction of individual graphene oxide sheets

• Yue Shen,
• Ying Wang,
• Yuan Zhou,
• Chunxi Hai,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 1146–1155, doi:10.3762/bjnano.9.106

• is biased. The sample, however, which is adhered to the sample holder with insulating double-sided adhesive, is not connected to ground. Thus the tip material has a capacitance similar to an isolated conductor and the rGO sheets or mica act as a dielectric in its electrostatic field, rather than

Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations

• Jaison Jeevanandam,
• Ahmed Barhoum,
• Yen S. Chan,
• Alain Dufresne and
• Michael K. Danquah

Beilstein J. Nanotechnol. 2018, 9, 1050–1074, doi:10.3762/bjnano.9.98

• into finer subcontacts, helps to clearly explain the insect body weight to setae trend. The natural adhesive system uses this principle for their design and may be incorporated in future practical applications. Research on attachment and mechanism of insects walking on ceilings using their hairy

• setae array endings by releasing greater adhesive strength [237][238][239]. The beautiful color patterns of peacock feathers are also known to be due to the cross-sectional arrangement of their feather frills as shown in Figure 7 [196]. Mollusk shells consists of “nacre”, which is a hierarchical

Scanning speed phenomenon in contact-resonance atomic force microscopy

• Christopher C. Glover,
• Jason P. Killgore and
• Ryan C. Tung

Beilstein J. Nanotechnol. 2018, 9, 945–952, doi:10.3762/bjnano.9.87

• thick [16][17] and is usually studied by measuring adhesive forces between the AFM tip and sample. Capillary necking between the adsorbed water layer and AFM tip creates additional adhesive forces that can be easily measured with a typical AFM system. These measurements are conducted using force pull

Tuning adhesion forces between functionalized gold colloidal nanoparticles and silicon AFM tips: role of ligands and capillary forces

• Sven Oras,
• Sergei Vlassov,
• Marta Berholts,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2018, 9, 660–670, doi:10.3762/bjnano.9.61

• agreement with experimentally measured adhesive values. In addition, the adhesion forces were evaluated between flat Au films functionalized with the same molecular components and silicon tips to exclude the effect of particle shape on the adhesion values. Although adhesion values on flat substrates were

• , electrostatic forces, H-bonding and capillary forces are crucial to understand the dependence of adhesive force on the type of functional layer. First, the high adhesion values of –SH and –NH2 coated NPs are explainable by the high polarizability of the molecules. Hence, adhesion forces acting between

• –OH functional group compared to those of –NH2 and –SH groups, a higher adhesion value might have been expected. However, this high polarity of the tail group also confers a high reactivity to Au NPs, especially with contamination in air. As a result, the final adhesive behavior of the Au coated NPs

Wafer-scale bioactive substrate patterning by chemical lift-off lithography

• Chong-You Chen,
• Chang-Ming Wang,
• Hsiang-Hua Li,
• Hong-Hseng Chan and
• Wei-Ssu Liao

Beilstein J. Nanotechnol. 2018, 9, 311–320, doi:10.3762/bjnano.9.31

• . Silicon substrates (Mustec Corp., Hsinchu, Taiwan) with 100 nm thick Au and 5 nm chromium adhesive layers were prepared by thermal evaporation. The Au substrates were immersed in 0.5 mM MCU or TEG ethanolic solution for >6 h to form self-assembled monolayers. After SAM formation, the substrates were

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

• performed by Mo et al. [77] for multiasperity contacts showed an excellent fit of this model with experimental data and the widely used Maugis–Dugdale single asperity adhesive theory model [78]. Despite the fact that such a good fit may be a result of the flexibility of the Maugis–Dugdale model, which masks

Humidity-dependent wound sealing in succulent leaves of Delosperma cooperi – An adaptation to seasonal drought stress

• Olga Speck,
• Mark Schlechtendahl,
• Florian Borm,
• Tim Kampowski and
• Thomas Speck

Beilstein J. Nanotechnol. 2018, 9, 175–186, doi:10.3762/bjnano.9.20

• the reading of data were performed by a measurement amplifier (Spider 8, Hottinger Baldwin Messtechnik GmbH). The ends of the samples were stuck to the sample holders with a rapid cyanoacrylate adhesive (Uhu Sekundenkleber blitzschnell Pipette, UHU GmbH and Co. KG Bühl, Germany). The samples were

• carefully arranged parallel to the tension forces to ensure an even strain field over the diameter of the sample. During hardening the adhesive glued samples were stored in a humidity chamber (>95% relative air humidity) in order to prevent or slow down dehydration (storage time for leaves: 2–4 h, storage

A robust AFM-based method for locally measuring the elasticity of samples

• Alexandre Bubendorf,
• Stefan Walheim,
• Thomas Schimmel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2018, 9, 1–10, doi:10.3762/bjnano.9.1

• reconstruction in UHV by contact force microscopy. They observed adhesive forces of up to 103 nN between the Si tip and the Si(111) surface. By coating the tip with PTFE (Teflon), they could reduce the sticking forces to 10 nN. A short scan on a PTFE sample led to a reliable coating of the tip for the subsequent

Dry adhesives from carbon nanofibers grown in an open ethanol flame

• Christian Lutz,
• Julia Syurik,
• C. N. Shyam Kumar,
• Christian Kübel,
• Michael Bruns and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 2719–2728, doi:10.3762/bjnano.8.271

• fabricated arrays of carbon nanofibers with different degrees of orientation. Inspired by the dry adhesive system of geckos we investigated the adhesive properties of such carbon nanofiber arrays with ordered and random orientation. AFM-based force spectroscopy revealed that adhesion force and energy rise

• applications, for instance, for the number of steps a climbing robot can execute before the adhesive layer needs to be replaced. Endurance tests, however, are time-consuming, which is the reason why most studies of CNF adhesives limit their adhesion measurement to a few cycles [11]. Here, we analyze the

Fabrication of CeO₂–MO_x (M = Cu, Co, Ni) composite yolk–shell nanospheres with enhanced catalytic properties for CO oxidation

• Ling Liu,
• Jingjing Shi,
• Hongxia Cao,
• Ruiyu Wang and
• Ziwu Liu

Beilstein J. Nanotechnol. 2017, 8, 2425–2437, doi:10.3762/bjnano.8.241

• treatment process, is regarded as a promising and effective approach to controllably design hollow structures with single and multilevel shells. The complexity of the shell structures is generally determined by the difference between the cohesive force (Fc) and the adhesive force (Fa) created by a proper

Involvement of two uptake mechanisms of gold and iron oxide nanoparticles in a co-exposure scenario using mouse macrophages

• Dimitri Vanhecke,
• Dagmar A. Kuhn,
• Dorleta Jimenez de Aberasturi,
• Sandor Balog,
• Ana Milosevic,
• Dominic Urban,
• Diana Peckys,
• Niels de Jonge,
• Wolfgang J. Parak,
• Alke Petri-Fink and
• Barbara Rothen-Rutishauser

Beilstein J. Nanotechnol. 2017, 8, 2396–2409, doi:10.3762/bjnano.8.239

• ]. Therefore, the occurrence of NP diffusion through pores in the membrane as well as passive uptake by van der Waals or steric interactions (subsumed as adhesive interactions) [25] cannot be excluded. The majority of uptake studies were conducted with one defined NP type only. However, since humans are more

Surfactant-induced enhancement of droplet adhesion in superhydrophobic soybean (Glycine max L.) leaves

• Oliver Hagedorn,
• Ingo Fleute-Schlachter,
• Hans Georg Mainx,
• Viktoria Zeisler-Diehl and
• Kerstin Koch

Beilstein J. Nanotechnol. 2017, 8, 2345–2356, doi:10.3762/bjnano.8.234

• of Glycine max L. were cut and fixed on a glass slide with double-sided adhesive tape (TESA, Beiersdorf, Germany). On the leaf samples, 20 µL of the aqueous surfactant solutions (at commonly used concentrations for ethoxylated seed oil adjuvants of 1 g/L [49][50]) were applied via a dispenser. The

• . Contact angle measurements For the contact angle measurements (before and after application of the surfactant solutions), leaf samples of approximately 1 cm2 were cut from the central area of the leaves and were fixed onto microscope glass slides with double-sided adhesive tape. Each value was obtained

• visualize the topography of the leaves, a 3D light microscope (Keyence VHX-600DSO, Keyence Deutschland GmbH, Germany) was used. Glycine max L. leaves were fixed on a flat glass slide with double-sided adhesive tape (Tesa, Germany) and images were taken from the side at magnifications between 10× and 30

Material property analytical relations for the case of an AFM probe tapping a viscoelastic surface containing multiple characteristic times

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2230–2244, doi:10.3762/bjnano.8.223

• excitation suddenly imposed during the impact. The third term is the relaxation modulus, and the fourth term is the adhesive portion of the van der Waals (vdW) interaction, in which HA is the Hamaker constant, R is the radius of the cylindrical punch, and a0 is the interatomic distance (ca. 0.2 nm) [39]. In

• (black star symbols) showing good agreement between the simulations and Equation 30 over the whole range of A/A0. Besides the main contributors, the adhesive component of the vdW interaction also adds to the total dissipated energy, because the tip–sample trajectory is not symmetric during the contact

• in Equation 31), and contributions proportional to the transients of the harmonic force (3rd term in Equation 31). All these contributions are plotted in Figure 5, following the same symbol scheme as for the case of dissipated energy in Figure 4. For clarity the contribution from the adhesive force