Biomimetic surface structures in steel fabricated with femtosecond laser pulses: influence of laser rescanning on morphology and wettability

• Camilo Florian Baron,
• Alexandros Mimidis,
• Daniel Puerto,
• Evangelos Skoulas,
• Emmanuel Stratakis,
• Javier Solis and
• Jan Siegel

Beilstein J. Nanotechnol. 2018, 9, 2802–2812, doi:10.3762/bjnano.9.262

• surface structures; laser rescanning; steel; wettability; Introduction Complex structures found in nature often present properties that are attractive for applications in science and technology. The hydrophobicity found at the lotus leaf surface [1], the exceptional adhesion capability of gecko feet [2

Optimization of Mo/Cr bilayer back contacts for thin-film solar cells

• Nima Khoshsirat,
• Fawad Ali,
• Vincent Tiing Tiong,
• Mojtaba Amjadipour,
• Hongxia Wang,
• Mahnaz Shafiei and
• Nunzio Motta

Beilstein J. Nanotechnol. 2018, 9, 2700–2707, doi:10.3762/bjnano.9.252

• .9.252 Abstract Molybdenum (Mo) is the most commonly used material as back contact in thin-film solar cells. Adhesion of Mo film to soda–lime glass (SLG) substrate is crucial to the performance of solar cells. In this study, an optimized bilayer structure made of a thin layer of Mo on an ultra-thin

• chromium (Cr) adhesion layer is used as the back contact for a copper zinc tin sulfide (CZTS) thin-film solar cell on a SLG substrate. DC magnetron sputtering is used for deposition of Mo and Cr films. The conductivity of Mo/Cr bilayer films, their microstructure and surface morphology are studied at

• different deposition powers and working pressures. Good adhesion to the SLG substrate has been achieved by means of an ultra-thin Cr layer under the Mo layer. By optimizing the deposition conditions we achieved low surface roughness, high optical reflectance and low sheet resistivity while we could decrease

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

• Weibin Wu,
• Christian Lutz,
• Simon Mersch,
• Richard Thelen,
• Christian Greiner,
• Guillaume Gomard and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2018, 9, 2618–2627, doi:10.3762/bjnano.9.243

• sandfish due to their ability to swim in loose, aeolian sand. Some studies report that this fascinating property of sandfish is accompanied by unique tribological properties of their skin such as ultra-low adhesion, friction and wear. The majority of these reports, however, is based on experiments

• conducted with a non-standard granular tribometer. Here, we characterise microscopic adhesion, friction and wear of single sandfish scales by atomic force microscopy. The analysis of frictional properties with different types of probes (sharp silicon tips, spherical glass tips and sand debris) demonstrates

• , it is highly unlikely that the surface structure of the scales is responsible for the observed low abrasion. Baumgartner and co-workers [10][11][16] measured adhesion by atomic force microscopy (AFM) on scales of S. scincus and observed extremely low values. They analysed the chemical composition of

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

• were reported [15][16][27][28]. This is true for the dimple diameter [15][27][28], as well as for the dimple depth [16][28]. Size effects are a common phenomenon in materials science and have been found to influence mechanical and magnetic as well as surface properties like adhesion [38][39][40][41

Cytotoxicity of doxorubicin-conjugated poly[N-(2-hydroxypropyl)methacrylamide]-modified γ-Fe₂O₃ nanoparticles towards human tumor cells

• Zdeněk Plichta,
• Yulia Kozak,
• Rostyslav Panchuk,
• Viktoria Sokolova,
• Matthias Epple,
• Lesya Kobylinska,
• Pavla Jendelová and
• Daniel Horák

Beilstein J. Nanotechnol. 2018, 9, 2533–2545, doi:10.3762/bjnano.9.236

• stability in aqueous media and limited internalization by the cells, however, enabled adhesion to the cell surface. While the neat PHPMA-coated particles proved to be non-toxic, doxorubicin-conjugated particles exhibited enhanced cytotoxicity in both drug-sensitive and drug-resistant tumor cells compared to

• , however, still under study. It can be concluded that the newly designed γ-Fe2O3@P(HPMA-MMAA)-Dox nanoparticles are highly promising for the delivery of cancer medications into tumors, offering enhanced cell adhesion, increased apoptosis, minimal immunogenicity, lipid peroxidation, DNA damage, and reduced

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

• , the method of dimensionality reduction [24][25] has been extended to the axisymmetric frictionless contact of elastically graded materials [26], and solutions are also provided in the presence of adhesion [27]. In all these cases, the elastic gradients are considered with respect to the depth, with an

ZnO-nanostructure-based electrochemical sensor: Effect of nanostructure morphology on the sensing of heavy metal ions

• Marina Krasovska,
• Vjaceslavs Gerbreders,
• Irena Mihailova,
• Andrejs Ogurcovs,
• Eriks Sledevskis,
• Andrejs Gerbreders and
• Pavels Sarajevs

Beilstein J. Nanotechnol. 2018, 9, 2421–2431, doi:10.3762/bjnano.9.227

• obtaining ZnO nanostructures in various morphologies, such as ZnO nanoneedles, nanorods, nanotubes, nanoplates, etc. Also the purpose of our previous research was to identify optimal growth parameters for obtaining a homogeneous, dense, well-aligned nanostructured ZnO coating with good adhesion to hard

• with a ZnO seed layer in order to provide adhesion of the nanostructured ZnO film to the glass surface, as well as epitaxial growth and the vertical alignment of nanostructures. It was prepared by dip coating using 5 mM zinc acetate (Zn(O2CCH3)2) solution in ethanol. The seed layer film was dried in a

Adhesive contact of rough brushes

• Qiang Li and
• Valentin L. Popov

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

• structure and an elastic half-space is numerically simulated using the fast Fourier transform (FFT)-based boundary element method and the mesh-dependent detachment criterion of Pohrt and Popov. The problem is of interest in light of the discussion of the role of contact splitting in the adhesion strength of

• 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

High-throughput micro-nanostructuring by microdroplet inkjet printing

• Hendrikje R. Neumann and
• Christine Selhuber-Unkel

Beilstein J. Nanotechnol. 2018, 9, 2372–2380, doi:10.3762/bjnano.9.222

• BCML can be biofunctionalized such that they serve as biomimetic anchorage sites for cell adhesion molecules, whereby their spacing has been shown to be highly decisive for cell adhesion [14]. Still, the anchorage site spacing required for cell adhesion depends on the chemistry of a particular adhesion

• ligand [15]. It has even been reported that cells can respond to differences in ligand spacing as small as 1 nm across the cell diameter [16]. Therefore, the fabrication of complex patterns of gold nanoparticles is highly relevant in the context of the biomimicry of cell adhesion environments. Whereas

Nanotribology

• Enrico Gnecco,
• Susan Perkin,
• Andrea Vanossi and
• Ernst Meyer

Beilstein J. Nanotechnol. 2018, 9, 2330–2331, doi:10.3762/bjnano.9.217

• : nanotribology; nanoadhesion; nanofriction; Nanotribology is a young and dynamic field of research which aims to investigate friction, wear and adhesion phenomena down to the nanometer scale. Since these phenomena occur in all natural, artificial or conceptual situations involving two surfaces (at least) in

Metal–dielectric hybrid nanoantennas for efficient frequency conversion at the anapole mode

• Valerio F. Gili,
• Lavinia Ghirardini,
• Davide Rocco,
• Giuseppe Marino,
• Ivan Favero,
• Iännis Roland,
• Giovanni Pellegrini,
• Lamberto Duò,
• Marco Finazzi,
• Luca Carletti,
• Andrea Locatelli,
• Aristide Lemaître,
• Dragomir Neshev,
• Costantino De Angelis,
• Giuseppe Leo and
• Michele Celebrano

Beilstein J. Nanotechnol. 2018, 9, 2306–2314, doi:10.3762/bjnano.9.215

• SiOx are deposited on the surface via plasma-enhanced chemical vapor deposition (PECVD) to later improve the adhesion of the negative-tone HSQ resist on the III–V layer. A first positive-tone lithography step with PMMA resist is performed to realize the alignment structures, followed by electron beam

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

• 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

• . Keywords: adhesive footprint; atomic force microscopy; nanomechanical properties; sea urchin; temporary adhesion; Introduction Unlike the thin homogeneous films that are typical for adhesives produced by humans, biological adhesives present complex hierarchical micro- and nanostructures. Among marine

• such as Entobdella solae temporarily attach to fish skin using anterior pads located in the head [1]. Adhesion is brought about by interaction between two kinds of glandular secretions which are extruded together to form the adhesive [11]. The later consists of a network of highly insoluble

Spin-coated planar Sb₂S₃ hybrid solar cells approaching 5% efficiency

• Pascal Kaienburg,
• Benjamin Klingebiel and
• Thomas Kirchartz

Beilstein J. Nanotechnol. 2018, 9, 2114–2124, doi:10.3762/bjnano.9.200

• crystalline phase of Sb2S3 for a thin layer on a mesoporous TiO2 scaffold [22][57]. For PDS measurements of the Sb-TU process, a TiO2 layer was spray-coated onto the glass before depositing the Sb2S3 layer because non-optimal adhesion prevents direct coating of glass with Sb-TU solution. The deposition

• nm. Layers for SEM and AFM imaging were prepared on FTO TEC7 substrates by Pilkington after spray-coating of TiO2. Layers for PDS and UV–vis measurements were coated directly on Corning glass since – in contrast to the Sb-TU route – adhesion on glass was uncritical. Sb2S3 was exclusively processed

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

• material stays behind on the substrate as a 'footprint'. In recent years, characterization of sea star temporary adhesion has been focussed on the forcipulatid species Asterias rubens. Results: We investigated the temporary adhesion system in the distantly related valvatid species Asterina gibbosa. The

• adhesion and might facilitate the development of biomimetic, reversible glues. Keywords: duo-gland adhesive system; lectins; marine temporary adhesion; starfish; Introduction Marine biological adhesives are environmentally friendly, biodegradable, and adhere to various surfaces in the challenging

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

• sliding nanosystems. This was demonstrated, e.g., for sheared graphite stacks [49], where nanomanipulation experiments also allowed the authors to determine the adhesion forces between the sliding graphite surfaces, simply by distinguishing between reversible displacement forces related to the

• conservative adhesion energy and irreversible friction forces. The same mechanisms of adhesion-driven forces in combination with structural lubricity have recently been observed for other systems as well. First, adhesion was found as the driving force for the formation of graphene nanoribbons by a self tearing

• process after nanoindentation experiments [73]. Secondly, also the self-retracting motion of graphene nanostacks can be explained if tiny friction forces, i.e., superlubric friction [3], are overcome by the adhesion-driven forces [50][51]. At the same time, the self-retracting motion of graphene stacks

Biomimetic and biodegradable cellulose acetate scaffolds loaded with dexamethasone for bone implants

• Aikaterini-Rafailia Tsiapla,
• Varvara Karagkiozaki,
• Veroniki Bakola,
• Foteini Pappa,
• Panagiota Gkertsiou,
• Eleni Pavlidou and
• Stergios Logothetidis

Beilstein J. Nanotechnol. 2018, 9, 1986–1994, doi:10.3762/bjnano.9.189

• . Cytotoxicity studies were performed by using MTT assay, methylene-blue staining and SEM fixation and showed very good cell adhesion and proliferation, indicating the cytocompatibility of these fibrous scaffolds. Drug-release kinetics was measured for the evaluation of a controllable and sustained release of

• results of the samples in contact with L929 cells are shown in Figure 8. The absorbance values of both scaffolds on the first day compared to the control group (cells only) were sufficiently high, indicating the initial adhesion of the cells to the surface. Then, the cell population gradually increased

Electromigrated electrical optical antennas for transducing electrons and photons at the nanoscale

• Arindam Dasgupta,
• Mickaël Buret,
• Nicolas Cazier,
• Marie-Maxime Mennemanteuil,
• Reinaldo Chacon,
• Kamal Hammani,
• Jean-Claude Weeber,
• Juan Arocas,
• Laurent Markey,
• Gérard Colas des Francs,
• Alexander Uskov,
• Igor Smetanin and
• Alexandre Bouhelier

Beilstein J. Nanotechnol. 2018, 9, 1964–1976, doi:10.3762/bjnano.9.187

• a 2 nm thick Cr or Ti adhesion layer to improve gold adhesion on the glass substrate. A scanning electron micrograph of a pristine 150 nm wide Au constriction formed between two bow-tie leads is exemplified in Figure 1a. The electrical connections of the constriction to outside control electronics

• . The thickness of the nanowire and electrodes is 50 nm, including a 5 nm Ti adhesion layer. The third step is the dry etching of the TiO2 layer. For that, we first create an etching mask by electron-beam lithography, thermal deposition of a 30 nm thick nickel layer and lift-off. Reactive ion etching is

Preparation of micro/nanopatterned gelatins crosslinked with genipin for biocompatible dental implants

• Reika Makita,
• Tsukasa Akasaka,
• Seiichi Tamagawa,
• Yasuhiro Yoshida,
• Saori Miyata,
• Hirofumi Miyaji and
• Tsutomu Sugaya

Beilstein J. Nanotechnol. 2018, 9, 1735–1754, doi:10.3762/bjnano.9.165

• of the surface of biomaterials. Surface topographical patterns significantly affect cell adhesion, spreading, morphology, proliferation, and differentiation [1][2][3][4][5]. Surfaces with specific micro/nanopatterns have been developed in order to reduce platelet response [6], to regulate stem cell

• shapes, using genipin crosslinking, can easily fabricate “sharp” patterns that can control the morphology and vinculin expression of cells grown on these surfaces. This control of cell shape and vinculin expression by patterning is known to be able to control cell adhesion, function, and differentiation

Toward the use of CVD-grown MoS₂ nanosheets as field-emission source

• Geetanjali Deokar,
• Nitul S. Rajput,
• Junjie Li,
• Francis Leonard Deepak,
• Wei Ou-Yang,
• Nicolas Reckinger,
• Carla Bittencourt,
• Jean-Francois Colomer and
• Mustapha Jouiad

Beilstein J. Nanotechnol. 2018, 9, 1686–1694, doi:10.3762/bjnano.9.160

• dried overnight to let the water trapped underneath the MoS2 NSs to be removed naturally. Next, the sample was baked at 110 °C for 10 min to improve the uniformity and the adhesion to the substrate. Finally, the PMMA was dissolved in acetone. Physical characterization methods The morphology of

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

• ultrahigh vacuum. We measured very low friction forces compared to adhesion forces and found a modulation of lateral forces reflecting the atomic structure of the surfaces. Holding the force-microscopy tip stationary for some time did not lead to an increase in static friction, i.e., no contact ageing was

• and flat surface was investigated in slide–hold–slide experiments similar to those reported in [8], but under UHV conditions at low loads (ca. 0 nN, i.e., the load was controlled by adhesion). As the name “slide–hold–slide” suggests, a tip was slid in contact over a surface, then held stationary for a

• strong tip–sample adhesion. Sliding activated tips against Au(111) always resulted in a decrease of friction, both for activated SiOx/Si tips (Figure 4d) and activated Au/Si tips (Figure 4e). Additional information about the friction processes can be obtained by comparing topography features before and

Interaction-tailored organization of large-area colloidal assemblies

• Silvia Rizzato,
• Elisabetta Primiceri,
• Anna Grazia Monteduro,
• Adriano Colombelli,
• Angelo Leo,
• Maria Grazia Manera,
• Roberto Rella and
• Giuseppe Maruccio

Beilstein J. Nanotechnol. 2018, 9, 1582–1593, doi:10.3762/bjnano.9.150

• another beaker of milli-Q water at 100 °C for 60 s in order to increase the particle contact area on the substrate surface (and thus the adhesion forces) for preserving the electrostatically ordered configuration in the next steps [24]. Finally, the samples were rinsed again with milli-Q water at room

• deposited both on bare and positively charged functionalized substrates. In the case of bare substrates (samples labeled as BS), only few, rather isolated particles were observed on the surface. We ascribed these results to a poor adhesion between the particles and the substrate, leading the particles to

• removal of the particles not properly absorbed to the substrate by electrostatic interaction. Immersing the still wet sample in a boiling water bath allows preservation of the electrostatically assembled, ordered structure by increasing the particle contact area (and adhesion) on the substrate surface [24

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

• with the trade name Silver Nano™ in their washing machines, air conditioners, refrigerators, air purifiers and vacuum cleaners, which use ionic Ag NPs [34]. NPs and NSMs are extensively used in auto production: as fillers in tires to improve adhesion to the road, fillers in the car body to improve the

• are exposed via an extensive microscopic study. It has been shown that adhesion is ensured by sub-micrometric devices whereas flies and beetles rely on terminal setae that are of micrometer dimensions. The principle of contact mechanics, which shows that the adhesion leads to the splitting of contacts

• capillary attractive forces and molecular interactions [230] or van der Waals interactions leads to adhesion [231]. This may be due to the production of secretory fluids in the contact area by some animals (insects) [232][233][234], whereas others do not (spiders, geckos) [235][236], which makes the basic

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• peak force or tapping mode. Besides conventional topographic images, peak force mode yields several concomitant images which map mechanical properties of the sample, like adhesion, elastic modulus, dissipation and others [64]. The adhesion channel monitors tip–sample attractive forces along the imaging

• process, producing high-resolution adhesion maps [64]. Topographic tapping images were acquired at a setpoint ratio S = A/A0 = 0.8–0.9, where A0 and A are free and imaging amplitudes, respectively. For peak force imaging, topographic images were acquired at a peak force F = 1 nN. Photo-assisted

• covering a graphite microplate substrate. (b) High-resolution AFM image (adhesion channel in peak force mode – see Experimental section) of the RA monolayer. The inset shows its fast Fourier transform, evidencing well-defined periodical RA ripples (periodicity: 2.7 ± 0.1 nm). (c) Schematic representation

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

• the lack of formation of a thin water layer on the surfaces of the samples at low humidity. Figure 6 shows the recorded contact-resonance frequencies on mica under low- and high-humidity conditions. Figure 7 shows the measured adhesion force as a function of the relative humidity for different RH

• values for both mica and HOPG. On the hydrophilic mica sample, a distinct increase of measured adhesion forces is apparent with increasing relative humidity. This suggests the growth of the thin water film on mica with increasing relative humidity. The observed behavior of the adhesion force for

• phenomenon was not observed in the regime suggests that the additional water layers have changed the dynamics of the tip–sample interaction. Furthermore, higher adhesion forces found on mica at 70% RH might change the threshold speed needed to achieve hydrodynamic lift. Conclusion This work has shown the

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar

• thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion

• : adhesion; atomic force microscopy (AFM); graphene oxide (GO); nanoscale dielectric properties; reduced graphene oxide (RGO); Introduction The local dielectric distribution is a key factor that influences the physical properties and functionalities of various materials such as polymer nanocomposites [1][2