Current state of laser synthesis of metal and alloy nanoparticles as ligand-free reference materials for nano-toxicological assays

• Christoph Rehbock,
• Jurij Jakobi,
• Lisa Gamrad,
• Selina van der Meer,
• Daniela Tiedemann,
• Ulrike Taylor,
• Wilfried Kues,
• Detlef Rath and
• Stephan Barcikowski

Beilstein J. Nanotechnol. 2014, 5, 1523–1541, doi:10.3762/bjnano.5.165

• , Friedrich-Loeffler-Institut, Höltystr. 10, 31535 Neustadt, Germany 10.3762/bjnano.5.165 Abstract Due to the abundance of nanomaterials in medical devices and everyday products, toxicological effects related to nanoparticles released from these materials, e.g., by mechanical wear, are a growing matter of

• , mammalian cells and bacteria are considered. Keywords: albumin; gold-silver; implant alloy; laser ablation; nickel-titanium; size control; wear debris; Introduction The widespread use of medical implants consisting of metals (e.g., gold coatings [1]) and alloys (e.g., NiTi, CoCr, stainless steel) [2][3][4

• nanoscopic wear debris [6][7][8] which have been reported to accumulate in lymph nodes, bone marrow, liver and spleen [9]. In that context toxicological effects, including impaired DNA replication and cell growth as well as inflammatory responses, are meant to originate from release of toxic heavy metal ions

Dry friction of microstructured polymer surfaces inspired by snake skin

• Martina J. Baum,
• Lars Heepe,
• Elena Fadeeva and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2014, 5, 1091–1103, doi:10.3762/bjnano.5.122

• lead to a stronger abrasive wear on the tribo-pair. Nevertheless by such kind of surface modification, they were able to reduce the frictional coefficient. A comparison of these finding with the results of our study is only possible in a limited way, because they used for their investigation a

• that a decrease in frictional coefficient is due to the reduction of adhesive components of the frictional mechanisms [51][52]. Another approach to explain the reduction in frictional coefficient on many microstructured surfaces could be the possibility of trapping of loose wear particles within the

• microstructures and thereby the avoidance of further surface ploughing by these wear particles [38][48][50][53]. The gap between biologically and artificially microstructured surfaces can be closed by interpreting the microstructure of the SIMPS as lines and spaces, in which the lines are periodically interrupted

A nanometric cushion for enhancing scratch and wear resistance of hard films

• Katya Gotlib-Vainshtein,
• Olga Girshevitz,
• Chaim N. Sukenik,
• David Barlam and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2014, 5, 1005–1015, doi:10.3762/bjnano.5.114

• PDMS, kapton/polycarbonate, Si/SiO2. Furthermore, when PDMS is applied as an intermediate layer between a harder substrate and titania, marked improvement in the scratch resistance is achieved. This is shown by quantitative wear tests for silicon or kapton, by coating these substrates with PDMS which

• is subsequently capped by a titania layer, resulting in enhanced scratch/wear resistance. The physical basis of this effect is explored by means of Finite Element Analysis, and we suggest a model for friction reduction based on the "cushioning effect” of a soft intermediate layer. Keywords: finite

• also give substantial improvement in the wear and friction behavior [2]. A third approach, which has the major advantage of not changing the bulk polymer properties is to use inorganic coatings [9][10]. One such attempt to reduce sensitivity to scratching involves depositing an oxide coating on 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

• important for reduced friction and wear. Figure 9 shows examples of load–displacement curves at intermediate and high loads (left) along with topography maps of the nanoparticles over a 10 µm × 10 µm scan area and 2-D profiles before and after indentation (right). The intermediate and high loads were 500

• ). Compression tests, as well as indentation tests, simulate the types of contacts nanoparticles encounter during different friction and wear conditions. For this purpose, a tip approximately 3.5 µm in radius was used to carry out compression tests. Figure 10 shows a typical load displacement curve for

Friction behavior of a microstructured polymer surface inspired by snake skin

• Martina J. Baum,
• Lars Heepe and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2014, 5, 83–97, doi:10.3762/bjnano.5.8

• adaptation to reduce wear. Based on this extensive comparative study of different microstructured polymer samples, it was experimentally demonstrated that the friction-induced stick-slip behavior does not solely depend on the frictional coefficient of the contact pair. Keywords: fast Fourier transformation

• strongly depend on material properties of the sliding partners, the optimal stick-slip reducing dimension of microstructures must be engineered for every single technical application. Nevertheless, it could be a very effective way to reduce frictional energy loss and friction-induced wear. In the present

• optimization [17], reduction of wear rate [35] and as shown in our study at hand reduction in stick-slip motion with it. The reduction of stick-slip behavior is directly related to the reduction of wear. Additionally, "controlled" stick-slip motion compared to "uncontrolled", randomly appearing stick-slip

Reversible mechano-electrochemical writing of metallic nanostructures with the tip of an atomic force microscope

• Christian Obermair,
• Marina Kress,
• Andreas Wagner and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2012, 3, 824–830, doi:10.3762/bjnano.3.92

• nanolithography, the results also help in understanding microscopic mechanisms of mechanically activated or mechanically assisted electrochemical processes on metallic surfaces, e.g., during electropolishing or in combined mechanical wear and corrosion processes. Experimental The experimental setup was described

Effect of spherical Au nanoparticles on nanofriction and wear reduction in dry and liquid environments

• Dave Maharaj and
• Bharat Bhushan

Beilstein J. Nanotechnol. 2012, 3, 759–772, doi:10.3762/bjnano.3.85

• applications in liquids requiring controlled manipulation and targeting. On the macroscale, nanoparticles in solids and liquids have been shown to reduce friction and wear. On the nanoscale, atomic force microscopy (AFM) studies have been performed in single- and multiple-nanoparticle contact, in dry

• environments, to characterize friction forces and wear. However, limited studies in submerged liquid environments have been performed and further studies are needed. In this paper, spherical Au nanoparticles were studied for their effect on friction and wear under dry conditions and submerged in water. In

• single-nanoparticle contact, individual nanoparticles, deposited on silicon, were manipulated with a sharp tip and the friction force was determined. Multiple-nanoparticle contact sliding experiments were performed on nanoparticle-coated silicon with a glass sphere. Wear tests were performed on the

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

• skin samples. The reduction is similar to that on the nanoscale, since skin cream is a shear-thinning fluid as mentioned earlier. Figure 9b shows that the coefficient of friction decreases as the normal load increases. Increased surface roughening and a large quantity of wear debris are believed to be

• increased surface roughening and a large quantity of wear debris. The coefficient of friction of pig skin is larger than that of rat skin on the nanoscale. The effect of velocity, normal load, and relative humidity on pig skin has the same trend as that for rat skin both on the nano- and macroscale, as does

The memory effect of nanoscale memristors investigated by conducting scanning probe microscopy methods

• César Moreno,
• Carmen Munuera,
• Xavier Obradors and
• Carmen Ocal

Beilstein J. Nanotechnol. 2012, 3, 722–730, doi:10.3762/bjnano.3.82

• resistive-switching effect to nanoscale devices. It is worth mentioning here that, by comparing Figure 5a and Figure 5f we can rule out any tip effects in I–V measurements due to tip contamination or coating wear. The nonmodified regions of the LSMO films serve as an in situ quality test of the tip

Polymer blend lithography: A versatile method to fabricate nanopatterned self-assembled monolayers

• Cheng Huang,
• Markus Moosmann,
• Jiehong Jin,
• Tobias Heiler,
• Stefan Walheim and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2012, 3, 620–628, doi:10.3762/bjnano.3.71

• scanning force microscopy (SFM) techniques allow not only the imaging of the topography of surfaces but also the spatially resolved study of surface properties, such as the electrical, elastic, tribological and wear properties [11][12][13][14][15][16][17][18][19][20][21][22][23]. At the same time, scanning

Nanotribology at high temperatures

• Saurav Goel,
• Alexander Stukowski,
• Gaurav Goel,
• Xichun Luo and
• Robert L. Reuben

Beilstein J. Nanotechnol. 2012, 3, 586–588, doi:10.3762/bjnano.3.68

• friction and nearly zero wear [1]. Recent research, however, has shown a steep rise in the grazing friction during wearless sliding, primarily attributed to the adhesion between the interacting surfaces [2]. A major assumption in the atomistic simulation associated with this finding was the consideration

• when it is rubbed against low carbon ferrous alloys and pure iron [7]. A hypothesis was proposed by Paul et al. [8] ascribing the rapid chemical wear of diamond tips to the presence of unpaired d-shell electrons in the substrate. Utilizing this proposition, a research group from Bremen University

• more categorically against low carbon ferrous alloys. The wear of the diamond tip will change the contact area which will alter the frictional force as the latter depends linearly on the number of atoms that chemically interact across the surface [10]. Then, the question arises as to what other options

Combining nanoscale manipulation with macroscale relocation of single quantum dots

• Francesca Paola Quacquarelli,
• Richard A. J. Woolley,
• Martin Humphry,
• Jasbiner Chauhan,
• Philip J. Moriarty and
• Ashley Cadby

Beilstein J. Nanotechnol. 2012, 3, 324–328, doi:10.3762/bjnano.3.36

• , we can ascertain the minimum amount of surface–tip contact force required for the manipulation to take place; reducing tip wear and image degradation. Tip state also plays an important role in the manipulation process, and the automatic characterisation and optimization of the AFM tip apex would be

Direct-write polymer nanolithography in ultra-high vacuum

• Woo-Kyung Lee,
• Minchul Yang,
• Arnaldo R. Laracuente,
• William P. King,
• Lloyd J. Whitman and
• Paul E. Sheehan

Beilstein J. Nanotechnol. 2012, 3, 52–56, doi:10.3762/bjnano.3.6

• silicon tip. Note that recent advances – where the tips remain sharp due to a coating of wear-resistant diamond – readily show line thicknesses of 40 nm [17]. The line width and heights were measured as a function of the probe speed (Figure 3). The heights of the deposited polymer structures roughly

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

Self-assembly at solid surfaces

• Sidney R. Cohen and
• Jacob Sagiv

Beilstein J. Nanotechnol. 2011, 2, 824–825, doi:10.3762/bjnano.2.91

• examination, prevention of spreading of liquids, friction and wear reduction, and surface passivation and protection. Whereas the early study of such monolayers indeed attracted considerable attention over the years, perhaps their greatest impact was yet to come, in new directions of research that could not

Formation of SiC nanoparticles in an atmospheric microwave plasma

• Martin Vennekamp,
• Ingolf Bauer,
• Matthias Groh,
• Evgeni Sperling,
• Susanne Ueberlein,
• Maksym Myndyk,
• Gerrit Mäder and
• Stefan Kaskel

Beilstein J. Nanotechnol. 2011, 2, 665–673, doi:10.3762/bjnano.2.71

• size is mainly influenced by the concentration of the precursor material in the plasma. Keywords: atmospheric microwave plasma; nanoparticle; SiC; Introduction Silicon Carbide (SiC) is a solid with various applications in materials science. It is used, e.g., as a wear-resistant material, as a

Manipulation of gold colloidal nanoparticles with atomic force microscopy in dynamic mode: influence of particle–substrate chemistry and morphology, and of operating conditions

• Samer Darwich,
• Karine Mougin,
• Akshata Rao,
• Enrico Gnecco,
• Shrisudersan Jayaraman and
• Hamidou Haidara

Beilstein J. Nanotechnol. 2011, 2, 85–98, doi:10.3762/bjnano.2.10

• different types of particle motion during manipulation, such as sliding, rolling, stick-slip and spinning, is crucial since the mode of motion of particles determines the energy loss and wear in the contacting surfaces. In this paper, the sensitivity of those critical parameters on the mobility of gold

Review of "Contact Mechanics and Friction: Physical Principles and Applications" by Valentin L. Popov

• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2011, 2, 57–58, doi:10.3762/bjnano.2.7

• ) nanomachines: micro and nano-actuators, (8) frictionally induced vibrations, (9) thermal effects in contacts, (10) lubricated systems, (11) viscoelastic properties and friction of elastomers, (12) wear. The book is an excellent example of interdisciplinary science because it uses approaches from physics

The description of friction of silicon MEMS with surface roughness: virtues and limitations of a stochastic Prandtl–Tomlinson model and the simulation of vibration-induced friction reduction

• W. Merlijn van Spengen,
• Viviane Turq and
• Joost W. M. Frenken

Beilstein J. Nanotechnol. 2010, 1, 163–171, doi:10.3762/bjnano.1.20

• and wear problems [12]. The question is now how to describe friction on the larger scale of actual MEMS devices, which pair micrometer features and nanometer-scale surface roughness with nano- to micro-Newton forces. This friction is characterized by irregular, but repeatable, stick-slip motion. Can

• surface asperities [26]. The static shear strength itself is determined by OH-bridging forces between the surfaces, direct chemical Si–O–Si bonds between the surfaces (the rupturing of these bonds leads to wear of the surfaces in the long run), and/or possibly liquid water meniscus strain or even gluing

• an average over 1000 scans. The fact that the slips appear sharp means that there was no significant change to their position over these 1000 scans and hence no surface changes (which would indicate wear). [Reprinted with permission from van Spengen, W. M.; Frenken, J. W. M. Tribol. Lett. 2007, 28

Scanning probe microscopy and related methods

• Ernst Meyer

Beilstein J. Nanotechnol. 2010, 1, 155–157, doi:10.3762/bjnano.1.18

• gives insight into fascinating phenomena, such as metal-superconductor transitions or metal-insulator transitions. Another important development is related to nanomechanics, where phenomena, such as friction, wear, elasticity and plasticity are studied on an atomic scale. Atomic friction has been

• information about the local bonding and to explore friction and wear mechanisms. Two different regimes were observed, which were related to the commensurability of the contacts [9]. The manipulation of a large number of particles gives also access to the size and shapes of the particles [10] and is discussed