Experimental investigation of usage of POE lubricants with Al₂O₃, graphene or CNT nanoparticles in a refrigeration compressor

• Kayhan Dağıdır and
• Kemal Bilen

Beilstein J. Nanotechnol. 2023, 14, 1041–1058, doi:10.3762/bjnano.14.86

• becoming more and more common due to their unique thermal properties [14]. Akkaya et al. [15] experimentally explored the lubrication properties of sepiolite (SP) and its carbon composites carbon black (CB), MWCNT, and reduced graphene oxide (rGO) in a refrigeration compressor. Consequently, the addition

Biomimetics on the micro- and nanoscale – The 25th anniversary of the lotus effect

• Matthias Mail,
• Kerstin Koch,
• Thomas Speck,
• William M. Megill and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2023, 14, 850–856, doi:10.3762/bjnano.14.69

• repellency, but also on the capability of some surfaces to keep stable air layers under water – the so-called Salvinia Effect. Such air layers are of great importance for drag reduction (passive air lubrication), antifouling, sensor applications, or oil–water separation. Up to now, based on the

Dry under water: air retaining properties of large-scale elastomer foils covered with mushroom-shaped surface microstructures

• Matthias Mail,
• Stefan Walheim,
• Thomas Schimmel,
• Wilhelm Barthlott,
• Stanislav N. Gorb and
• Lars Heepe

Beilstein J. Nanotechnol. 2022, 13, 1370–1379, doi:10.3762/bjnano.13.113

• Effect, the capability to keep a stable air layer when submerged under water. Such air layers are of great importance, e.g., for drag reduction (passive air lubrication), antifouling, sensor applications or oil–water separation. Some biological models, e.g., the floating fern Salvinia or the backswimmer

• air lubrication; Salvinia effect; superhydrophobicity; Introduction Superhydrophobicity is one of the key innovations in the biological evolution of organisms for the conquest of land [1]. Recently it was shown that this fascinating surface property evolved already in the cyanobacterium Hassallia [2

Effect of lubricants on the rotational transmission between solid-state gears

• Huang-Hsiang Lin,
• Jonathan Heinze,
• Alexander Croy,
• Rafael Gutiérrez and
• Gianaurelio Cuniberti

Beilstein J. Nanotechnol. 2022, 13, 54–62, doi:10.3762/bjnano.13.3

• formation process between gears. Keywords: lubricants; MD simulation; rotational transmission; solid-state gears; Introduction In mechanical systems, lubrication is the most common way to reduce friction and wear [1][2][3][4]. The idea of lubricants is preventing direct contact between surfaces to avoid

• dry friction from asperities and wear. Hence, the desirable lubrication regime would be hydrodynamic or elastohydrodynamic lubrication in the Stribeck curve [5]. The former corresponds to the situation that surfaces are completely separated by a fluid. The latter is similar but surface deformations

Quantitative determination of the interaction potential between two surfaces using frequency-modulated atomic force microscopy

• Nicholas Chan,
• Carrie Lin,
• Tevis Jacobs,
• Robert W. Carpick and
• Philip Egberts

Beilstein J. Nanotechnol. 2020, 11, 729–739, doi:10.3762/bjnano.11.60

• interactions necessitates characterization methods with angstrom-level precision. Therefore, techniques such as atomic force microscopy (AFM) are often used to evaluate the performance of these surface modification approaches. The interpretation of lubrication and surface modification behavior via AFM

Tungsten disulfide-based nanocomposites for photothermal therapy

• Tzuriel Levin,
• Hagit Sade,
• Rina Ben-Shabbat Binyamini,
• Maayan Pour,
• Iftach Nachman and
• Jean-Paul Lellouche

Beilstein J. Nanotechnol. 2019, 10, 811–822, doi:10.3762/bjnano.10.81

• the most extensively studied members in this group, and are used for, e.g., polymer reinforcement, lubrication and electronic devices. Their biocompatibility and low toxicity make them suitable for medical and biological applications. One potential application is photothermal therapy (PTT), a method

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

• achieved for mixed lubrication contacts [15][16]. While these traditional texturing elements have been studied for decades and by numerous research groups worldwide, in recent years, a new paradigm has emerged. Researchers have started to look to biology in search for morphological textures that would

• demonstrate the existence of size effects under mixed lubrication [16][27] as well as for the transition from static to dynamic friction in dry contacts [28]. This paper presents results for two independent sets of experiments aiming at investigating the existence of a similar size effect for scale-like

• friction forces encountered for sliding speeds between 40 and 70 mm/s. For even slower sliding, a more classical mixed lubrication contact is formed, as it is also encountered for samples textured with dimples [15]. The surface roughness of the steel discs after the experiments was Ra ≈ 200 nm. The discs

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

• of the indentation of materials with an exponential or power law variation of the Young’s modulus through the depth [20][21]. Giannakopoulos and Pallot then extended the analysis to 2D [22]. Graded substrates have also been considered in elastohydrodynamic lubrication problems [23]. More recently

Nanotribology

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

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

• India, China, Argentina, Cameroon, Russia and USA back to many countries in Old Europe). The covered topics include lubrication, surface preparation and theoretical models of friction at the nanoscale. Regarding the first topic, this Thematic Series gives examples of cutting-edge aqueous solutions

• ., silicon oxide, are recognized. The quality of the surface condition is addressed experimentally by the example of cryogenically treated martensitic stainless steel [4] and theoretically by an analysis of the influence of micro-dimple textures on hydrodynamic lubrication [5]. On a more fundamental level

• , different authors have modeled the influence of electrical double layers on hydrodynamic lubrication [6], the occurrence of a second-order phase transition in ultrathin lubricant films [7] and the velocity dependence of dry friction on crystal surfaces at the atomic scale [8]. While many experimental

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

• research would exceed our resources, and take us too far in extent. We organize the selected topics in sections as follows: We first report on the progress in nanomanipulation, i.e., controlled movements at the nanometer scale. The successive section focuses on nano-confined lubrication. Then section

• heterogeneous contacts formed between hexagonal boron nitride clusters and graphene, a recent study has pointed out how kinetic friction can drastically decrease when the slider enters a regime of soliton-supported smooth sliding beyond a certain contact area [79]. Confined systems and lubrication Several

• research groups have been investigating the frictional properties of nanoscale systems confined between two sliding blocks. This intendedly vague indication of “systems” includes liquid lubricants in the boundary-lubrication regime, but also solid lubricants such as graphite or graphene or MoS2 flakes

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

• structure [10], for which friction maxima have been predicted [11]. Friction force microscopy (FFM) is a key method to investigate the microscopic mechanisms underlying friction, wear, and lubrication as it allows for measurements of static and kinetic friction of single nanometer-scale contacts. In FFM, an

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

• that more advanced, geometrically accurate models exist. However, we expect the general trends in the hydrodynamic lift force to remain unchanged. We begin with the Reynolds lubrication equation for a planar channel given by: where p(x) is the pressure in the channel, h is the gap height, μ is the

• hydrodynamic theory. Further research must be conducted to study the effect that a thin, highly ordered, viscous water layer has on the dynamics of the tip–sample contact at various relative humidity and on hydrophilic and hydrophobic samples. Hydrodynamic lubrication phenomenon. (a) The AFM tip is in intimate

• nN force set-point (SP), respectively). The black and red lines represent the percent error calculated by the lubrication theory given in Equation 3 and Equation 4. The percent error was calculated using the measured stationary sample stiffness of mica (ks = 350 N/m) and the equation for the

Graphene composites with dental and biomedical applicability

• Sharali Malik,
• Felicite M. Ruddock,
• Adam H. Dowling,
• Kevin Byrne,
• Wolfgang Schmitt,
• Ivan Khalakhan,
• Yoshihiro Nemoto,
• Hongxuan Guo,
• Lok Kumar Shrestha,
• Katsuhiko Ariga and
• Jonathan P. Hill

Beilstein J. Nanotechnol. 2018, 9, 801–808, doi:10.3762/bjnano.9.73

• removed from the mould, inspected and specimens containing visual defects were discarded. The flat ends of the specimens were hand-lapped on P600 silicon carbide paper (Beuhler, Lake Bluff, Illinois, USA) under water lubrication to ensure parallel specimen ends for uniform contact with the platens of the

Numerical investigation of the tribological performance of micro-dimple textured surfaces under hydrodynamic lubrication

• Kangmei Li,
• Dalei Jing,
• Jun Hu,
• Xiaohong Ding and
• Zhenqiang Yao

Beilstein J. Nanotechnol. 2017, 8, 2324–2338, doi:10.3762/bjnano.8.232

• controlling the tribological behavior of friction pairs used in mechanical and biological engineering. In this study, by utilizing the method of three-dimensional computational fluid dynamics (CFD) simulation, the lubrication model of a friction pair with micro-dimple array was established based on the Navier

• total integration of the pressure is positive, which can increase the load-carrying capacity of a friction pair. The effects of the micro-dimple parameters as well as fluid properties on tribological performance were investigated. It was concluded that under the condition of hydrodynamic lubrication

• simulation; hydrodynamic lubrication; micro-dimple array; surface texture; tribological performance; Introduction The wear caused by friction is considered to be the main reason for the failure of mechanical systems and the major source of energy loss [1]. Various methods have been developed to reduce

Velocity dependence of sliding friction on a crystalline surface

• Christian Apostoli,
• Giovanni Giusti,
• Jacopo Ciccoianni,
• Gabriele Riva,
• Rosario Capozza,
• Rosalie Laure Woulaché,
• Andrea Vanossi,
• Emanuele Panizon and
• Nicola Manini

Beilstein J. Nanotechnol. 2017, 8, 2186–2199, doi:10.3762/bjnano.8.218

• this method is quite effective in the context of fluid boundary lubrication, in the context of dry friction and crystalline interfaces nontrivial couplings of longitudinal and transverse modes [32][41][42] may lead to undesired γ-dependent effects. In the present work we propose a different, minimalist

A comparative study of the nanoscale and macroscale tribological attributes of alumina and stainless steel surfaces immersed in aqueous suspensions of positively or negatively charged nanodiamonds

• Colin K. Curtis,
• Antonin Marek,
• Alex I. Smirnov and
• Jacqueline Krim

Beilstein J. Nanotechnol. 2017, 8, 2045–2059, doi:10.3762/bjnano.8.205

• pressing need to replace hazardous additive materials in present-day oil-based lubrication technologies and to eliminate the serious environmental risks associated with oil leakage and disposal [3][4][5]. Water-based lubricant systems are a particularly attractive target for nanoparticulate additives since

• suspensions have received far less attention [1][2][7][8][9]. Although the low shear strength of water is beneficial in the hydrodynamic regime of lubrication, under normal loads it also enables contact between opposing surfaces. Nanoparticulate additives have the potential to overcome this deficiency, by

• at this time in order for the field to progress and for accurate model predictions to be developed. QCM is emerging as an ideal tool for studying the fundamental mechanisms associated with nanoparticle lubrication [9]. While historically it was developed as a time standard and a deposition rate

Imidazolium-based ionic liquids used as additives in the nanolubrication of silicon surfaces

• Patrícia M. Amorim,
• Ana M. Ferraria,
• Rogério Colaço,
• Luís C. Branco and
• Benilde Saramago

Beilstein J. Nanotechnol. 2017, 8, 1961–1971, doi:10.3762/bjnano.8.197

• . Although the use of ionic liquids (ILs) as additives to base oils in the lubrication of steel/steel or other types of metal/ metal tribological pairs has been investigated, the number of studies involving Si is very low. In this work, we tested imidazolium-based ILs as additives to the base oil

• rose as an attractive alternative from the economical point of view, and it has been pointed out in previous studies [2][3]. The first investigation reporting the use of ILs as additives is, to our knowledge, the work of Phillips et al. [4], who added imidazolium-based ILs to water for the lubrication

• imidazolium-based cations and the anions [BF4], hexafluorophosphate [PF6] and [NTf2] as additives to PEG and polyurea grease in the lubrication of steel/steel pairs, at room temperature and high temperatures. Recently, Pejaković et al. [14] tested several imidazolium sulfate ILs and found significant

The effect of the electrical double layer on hydrodynamic lubrication: a non-monotonic trend with increasing zeta potential

• Dalei Jing,
• Yunlu Pan and
• Xiaoming Wang

Beilstein J. Nanotechnol. 2017, 8, 1515–1522, doi:10.3762/bjnano.8.152

• effect of lubricant is established to investigate the effect of the EDL on the hydrodynamic lubrication of a 1D slider bearing. The theoretical model is based on the nonlinear Poisson–Boltzmann equation without the use of the Debye–Hückel approximation. Furthermore, the variation in the bulk electrical

• conductivity of the lubricant under the influence of the EDL is also considered during the theoretical analysis of hydrodynamic lubrication. The results show that the EDL can increase the hydrodynamic load capacity of the lubricant in a 1D slider bearing. More importantly, the hydrodynamic load capacity of the

• lubricant under the influence of the EDL shows a non-monotonic trend, changing from enhancement to attenuation with a gradual increase in the absolute value of the zeta potential. This non-monotonic hydrodynamic lubrication is dependent on the non-monotonic electroviscous effect of the lubricant generated

Development of a nitrogen-doped 2D material for tribological applications in the boundary-lubrication regime

• Shende Rashmi Chandrabhan,
• Velayudhanpillai Jayan,
• Somendra Singh Parihar and
• Sundara Ramaprabhu

Beilstein J. Nanotechnol. 2017, 8, 1476–1483, doi:10.3762/bjnano.8.147

• nanolubricant in an induced draft (ID) fan results in the remarkable decrease in the power consumption. Keywords: friction; lubrication; nanolubricant; nitrogen-doped reduced graphene oxide; tribology; wear; Introduction Advances in machine technology necessitate the reduction in energy loss by improving the

• mechanical technologies. Recent development in lubricant technology reveals that the tribological performance of conventional lubricants can be improved by the addition of the solid particles [1][2][3][4][5][6]. When boundary lubrication occurs the asperities of the sliding surfaces are in direct contact

• with each other despite the presence of lubricant. Thus, the load is actually carried by the surface asperities [7]. The addition of solid particles is advantageous in the boundary-lubrication regime since the solid particles can move to the surface-contact region and improve the lubrication. This type

First examples of organosilica-based ionogels: synthesis and electrochemical behavior

• Andreas Taubert,
• Ruben Löbbicke,
• Barbara Kirchner and
• Fabrice Leroux

Beilstein J. Nanotechnol. 2017, 8, 736–751, doi:10.3762/bjnano.8.77

• : ionic liquids; ionogels; organosilica; proton conductivity; Introduction Ionic liquids (ILs), that is, substances solely composed of ionic species have been studied for virtually every application from organic synthesis to lubrication and battery technology [1][2][3][4]. A particularly promising field

Structural and tribometric characterization of biomimetically inspired synthetic "insect adhesives"

• Matthias W. Speidel,
• Malte Kleemeier,
• Andreas Hartwig,
• Klaus Rischka,
• Angelika Ellermann,
• Rolf Daniels and
• Oliver Betz

Beilstein J. Nanotechnol. 2017, 8, 45–63, doi:10.3762/bjnano.8.6

• hydrostatic or hydrodynamic lubrication (cf. [56]), our nanotribometric experiments revealed much higher shear stresses than the plate-plate rheology. Whereas most experimental conditions were basically comparable in both these methods, they differed in the obtained layer film thickness (gap size). In the

• and boundary lubrication effects [56] in combination with the viscoelastic properties of pliable tarsal cuticles. In our nanotribometric friction experiments involving low normal loads and high liquid film thicknesses, we did not determine shear stresses under the conditions of such very thin liquid

“Sticky invasion” – the physical properties of Plantago lanceolata L. seed mucilage

• Agnieszka Kreitschitz,
• Alexander Kovalev and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2016, 7, 1918–1927, doi:10.3762/bjnano.7.183

• . lanceolata seeds can be eaten by birds, and because of the mucilage, which provides lubrication, the seeds can pass easier through the digestive system of the birds to be spread via this means. Viable seeds of plantain were found in pigeons, sparrows, bullfinch, greenfinch and cattle droppings [5][8]. It was

Exploiting the hierarchical morphology of single-walled and multi-walled carbon nanotube films for highly hydrophobic coatings

• Francesco De Nicola,
• Paola Castrucci,
• Manuela Scarselli,
• Francesca Nanni,
• Ilaria Cacciotti and
• Maurizio De Crescenzi

Beilstein J. Nanotechnol. 2015, 6, 353–360, doi:10.3762/bjnano.6.34

• ], anti-fouling [47], anti-fogging [48], low-friction coatings [5], adsorption [30], lubrication [22], dispersion [44], and self-assembly [49]. Experimental Fabrication of carbon nanotube films Highly pure SWCNT powder (Sigma-Aldrich, assay >90%, diameter: 0.7–0.9 nm) and MWCNT powder (Nanocyl, NC7000

Aquatic versus terrestrial attachment: Water makes a difference

• Petra Ditsche and
• Adam P. Summers

Beilstein J. Nanotechnol. 2014, 5, 2424–2439, doi:10.3762/bjnano.5.252

• actually the force needed to shear the junctions formed between the surfaces in contact. In contrast, in wet friction a film of water or another liquid is involved. This liquid can originate from humidity in the air or from secretion by the animal. Under such boundary lubrication conditions there is a

• are fully immersed in water, we have a case of full-film lubrication. The surfaces are completely separated by the fluid and friction is defined by the nominal surface area and the viscosity of the fluid that has to be sheared. Moreover, in this case the surface tension is zero and no capillary forces

• spider walking under water, mixed lubrication might occur. In this case, friction is a mixture of cases of full-film lubrication and boundary lubrication. The growth of biofilms and fouling organisms on aquatic substrates can have a significant impact on friction. The decreased tenacity of Northern

Carbon nano-onions (multi-layer fullerenes): chemistry and applications

• Juergen Bartelmess and
• Silvia Giordani

Beilstein J. Nanotechnol. 2014, 5, 1980–1998, doi:10.3762/bjnano.5.207

• ][78][79][80]. Mechanisms by which CNOs can reduce friction and wear were investigated in greater detail in 2009 by Martin and collaborators in a combined experimental and computational study [81]. Computer simulations suggest that the lubrication of CNOs between two surfaces is caused by rolling