Electrostatic pull-in application in flexible devices: A review

• Teng Cai,
• Yuming Fang,
• Yingli Fang,
• Ruozhou Li,
• Ying Yu and
• Mingyang Huang

Beilstein J. Nanotechnol. 2022, 13, 390–403, doi:10.3762/bjnano.13.32

• microscale energy system. Triboelectric power generation: Two materials with different work functions will gain or lose electrons when they are in contact with each other, resulting in the triboelectric effect [90]. When the switch is closed, the electrode contact friction causes the surfaces to carry

• charges, forming a dielectric charging effect. Molinero et al. [52][53] characterized the dielectric charging when the switch electrodes were contacted and proved that the surface dielectric charging caused by friction would lead to a shift of the switch voltage and shorten the life cycles of the switch

Micro- and nanotechnology in biomedical engineering for cartilage tissue regeneration in osteoarthritis

• Zahra Nabizadeh,
• Mahmoud Nasrollahzadeh,
• Hamed Daemi,
• Mohamadreza Baghaban Eslaminejad,
• Ali Akbar Shabani,
• Mehdi Dadashpour,
• Majid Mirmohammadkhani and
• Davood Nasrabadi

Beilstein J. Nanotechnol. 2022, 13, 363–389, doi:10.3762/bjnano.13.31

• -friction, wear resistant surface for joint motion [6][7]. It is an avascular, aneural, alymphatic, and hypocellular tissue consisting of a single cell type (chondrocyte) dispersed in a dense matrix [6]. Chondrocytes, which constitute only about 5% of the wet weight of the articular cartilage, are

The effect of metal surface nanomorphology on the output performance of a TENG

• Yiru Wang,
• Xin Zhao,
• Yang Liu and
• Wenjun Zhou

Beilstein J. Nanotechnol. 2022, 13, 298–312, doi:10.3762/bjnano.13.25

• principles of TENGs converting mechanical energy into electrical energy are the friction electrification effect and the electrostatic induction principle. When two materials with different electronegativity are physically contacted, positive and negative electrostatic charges are generated on each material

•  9). Generally, due to the increase of contact area and surface charge density a higher friction electrical output is produced. Large copper nanoparticles have full contact with the polymer, but small copper nanoparticles have insufficient contact with the polymer or even no contact at all. Therefore

• , the improvement of friction electrical output performance is not obvious. Experiments 4, 5, and 15, which are shown in Figure 5 and Figure 6, respectively, yielded pyramidal copper nanoparticles with sharp surfaces. Among them, experiments 4 and 5 improved the output performance only by 18% to 19

Relationship between corrosion and nanoscale friction on a metallic glass

• Haoran Ma and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2022, 13, 236–244, doi:10.3762/bjnano.13.18

• are promising materials for microdevices, although corrosion and friction limit their effectiveness and durability. We investigated nanoscale friction on a metallic glass in corrosive solutions after different periods of immersion time using atomic force microscopy to elucidate the influence of

• corrosion on nanoscale friction. The evolution of friction upon repeated scanning cycles on the corroded surfaces reveals a bilayer surface oxide film, of which the outer layer is removed by the scanning tip. The measurement of friction and adhesion allows one to compare the physicochemical processes of

• surface dissolution at the interface of the two layers. The findings contribute to the understanding of mechanical contacts with metallic glasses under corrosive conditions by exploring the interrelation of microscopic corrosion mechanisms and nanoscale friction. Keywords: atomic force microscopy (AFM

Nanoscale friction and wear of a polymer coated with graphene

• Robin Vacher and
• Astrid S. de Wijn

Beilstein J. Nanotechnol. 2022, 13, 63–73, doi:10.3762/bjnano.13.4

• Robin Vacher Astrid S. de Wijn Corrosion and tribology, SINTEF, Richard Birkelands vei 2B, 7034 Trondheim, Norway Institutt for maskinteknikk og produksjon, NTNU, Richard Birkelands vei 2B, 7034 Trondheim, Norway 10.3762/bjnano.13.4 Abstract Friction and wear of polymers at the nanoscale is a

• challenging problem due to the complex viscoelastic properties and structure. Using molecular dynamics simulations, we investigate how a graphene sheet on top of the semicrystalline polymer polyvinyl alcohol affects the friction and wear. Our setup is meant to resemble an AFM experiment with a silicon tip. We

• have used two different graphene sheets, namely an unstrained, flat sheet, and one that has been crumpled before being deposited on the polymer. The graphene protects the top layer of the polymer from wear and reduces the friction. The unstrained flat graphene is stiffer, and we find that it constrains

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

• Huang-Hsiang Lin Jonathan Heinze Alexander Croy Rafael Gutierrez Gianaurelio Cuniberti Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden, Dresden, Germany 10.3762/bjnano.13.3 Abstract Lubricants are widely used in macroscopic mechanical systems to reduce friction

• 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

Topographic signatures and manipulations of Fe atoms, CO molecules and NaCl islands on superconducting Pb(111)

• Carl Drechsel,
• Philipp D’Astolfo,
• Jung-Ching Liu,
• Thilo Glatzel,
• Rémy Pawlak and
• Ernst Meyer

Beilstein J. Nanotechnol. 2022, 13, 1–9, doi:10.3762/bjnano.13.1

• features resemble typical patterns observed in friction force microscopy (FFM) [28][38] or scanning tunneling hydrogen microscopy (SThM) [70][71], since the trapped Fe atom senses the surface potential in analogy to the probing tip of FFM. For clarity, we overlay the Pb(111) surface lattice on top of the

Alteration of nanomechanical properties of pancreatic cancer cells through anticancer drug treatment revealed by atomic force microscopy

• Xiaoteng Liang,
• Shuai Liu,
• Xiuchao Wang,
• Dan Xia and
• Qiang Li

Beilstein J. Nanotechnol. 2021, 12, 1372–1379, doi:10.3762/bjnano.12.101

• smaller than that of the three PCCs. This could be caused by the difference of the internal friction and/or vicious damping [26][27] between the normal and the cancer cells. The relative Young’s modulus distributions of different kinds of cells, according to the nanomechanical mapping (Figure 3a–d) and

Polarity in cuticular ridge development and insect attachment on leaf surfaces of Schismatoglottis calyptrata (Araceae)

• Venkata A. Surapaneni,
• Tobias Aust,
• Thomas Speck and
• Marc Thielen

Beilstein J. Nanotechnol. 2021, 12, 1326–1338, doi:10.3762/bjnano.12.98

• different. Such unevenness in the exposure of the leaf to the external environment might result in the inclined ridge progression on the S. calyptrata leaves. Also, the presence of ridges on the leaf surfaces might reduce friction, thereby, avoiding damage between the delicate rolled leaf layers during

A review on slip boundary conditions at the nanoscale: recent development and applications

• Ruifei Wang,
• Jin Chai,
• Bobo Luo,
• Xiong Liu,
• Jianting Zhang,
• Min Wu,
• Mingdan Wei and
• Zhuanyue Ma

Beilstein J. Nanotechnol. 2021, 12, 1237–1251, doi:10.3762/bjnano.12.91

• shear viscosity of the liquid, equal to the friction stress suffered by the liquid from the wall, which is expressed as σ = λνs, where λ represents the interfacial friction coefficient [46]. Therefore, the slip length can be expressed as , which indicates that the slip length is reduced with the

• increase in the friction between liquid and solid surfaces. Since the interfacial friction coefficient can be expressed in terms of the Green–Kubo expression, the microscopic expression of slip length can be written as follows [1][46]: where S is the area of the solid wall and Fl is the component of the

• interaction energy, and water slippage (or friction coefficient) may also not have a one-to-one correspondence between each other [67][68][69]. Contrary to the conventional wisdom, where slip boundary conditions are not valied for water slippage on hydrophilic surfaces, some simulation observations show that

Two dynamic modes to streamline challenging atomic force microscopy measurements

• Alexei G. Temiryazev,
• Andrey V. Krayev and
• Marina P. Temiryazeva

Beilstein J. Nanotechnol. 2021, 12, 1226–1236, doi:10.3762/bjnano.12.90

• classical contact mode, the friction force can be measured; when using off-resonance dynamic modes, stiffness and adhesion in the samples can be determined. Obviously, in determining the mechanical properties, the force of tip–surface interaction should be somewhat greater than that required if the task is

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

• topography, for example, adhesion, phase shift, stiffness, work function, or friction. In the following section, the utility of CNN in SPM is illustrated through several examples taken from the literature. Enhancing speed of image acquisition As discussed above, SPM imaging is inherently slow. One of the

Recent progress in actuation technologies of micro/nanorobots

• Ke Xu and
• Bing Liu

Beilstein J. Nanotechnol. 2021, 12, 756–765, doi:10.3762/bjnano.12.59

• direction of magnetization of the ISME, f represents the force of friction, ω indicates the rotation velocity of the microsphere, and θ denotes the tilt angle between the direction of the magnetic field and the direction of magnetization of the ISME. (c) Velocity–frequency profiles for ISMEs with different

Recent progress in magnetic applications for micro- and nanorobots

• Ke Xu,
• Shuang Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2021, 12, 744–755, doi:10.3762/bjnano.12.58

• on diamagnetic levitation nanomaterials. Without using strong electromagnets or bulky permanent magnets, it can make the microrobot move in three dimensions in a liquid environment through diamagnetic levitation. The main purpose of this method is to eliminate friction between the substrate surface

Physical constraints lead to parallel evolution of micro- and nanostructures of animal adhesive pads: a review

• Thies H. Büscher and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2021, 12, 725–743, doi:10.3762/bjnano.12.57

• principles of attachment pads with a special focus on insects, describe micro- and nanostructures, surface patterns, origin of different pads and their evolution, discuss the material properties (elasticity, viscoelasticity, adhesion, friction) and basic physical forces contributing to adhesion, show the

• might be potentially interesting for engineers as a kind of optimal solution by nature, the biomimetic implications of the discussed results are briefly presented. Keywords: adhesion; attachment devices; biomechanics; convergence; friction; substrate compliance; Review Animal attachment systems

• generally contribute to the attachment on rough surfaces due to friction and mechanical interlocking [83][89][92][232][233][234][235][236]. The performance of claws depends on the radius of the claw tip in relation to the curvature of the surface irregularities [83][234][237][238]. However, in combination

Nanogenerator-based self-powered sensors for data collection

• Yicheng Shao,
• Maoliang Shen,
• Yuankai Zhou,
• Xin Cui,
• Lijie Li and
• Yan Zhang

Beilstein J. Nanotechnol. 2021, 12, 680–693, doi:10.3762/bjnano.12.54

• load [7]. To detect the state of wheels at high friction and at high speed, sensors based on a harsh-environmental TENG (he-TENG) can be included in a self-powered smart brake system. TENG-based vehicle sensors can collect data on driving habits, such as the frequency of using brake pedal and

Simulation of gas sensing with a triboelectric nanogenerator

• Kaiqin Zhao,
• Hua Gan,
• Huan Li,
• Ziyu Liu and
• Zhiyuan Zhu

Beilstein J. Nanotechnol. 2021, 12, 507–516, doi:10.3762/bjnano.12.41

• layer with very small separation distance (less than 1 mm) [25], and the effective contact area of the friction material is increased by texturing its surface [26][27] to improve its electrical output. This setup is widely applied in vertical contact separation mode [28][29], sliding mode [30][31

• ], single electrode mode [32][33][34], and independent layer mode [35]. In order to explain the charge transfer process between two friction materials in contact, various models have been proposed and explored, such as electron cloud model [36][37][38], ion transfer model [39], and material transfer model

• electrification and electrostatic induction. Contact electrification refers to the electron transfer between two different materials in contact because the atoms are so close together. An electric field is generated after friction electrification, and electrostatic induction is caused by the electric field. The

A stretchable triboelectric nanogenerator made of silver-coated glass microspheres for human motion energy harvesting and self-powered sensing applications

• Hui Li,
• Yaju Zhang,
• Yonghui Wu,
• Hui Zhao,
• Weichao Wang,
• Xu He and
• Haiwu Zheng

Beilstein J. Nanotechnol. 2021, 12, 402–412, doi:10.3762/bjnano.12.32

• is 1:1.5, VOC and ISC reach the largest values of 250 V and 6 μA, respectively, under a force of 150 N. As the content of SCGMs continues to increase, VOC and ISC gradually decrease. The larger amount of SCGMs causes less air in the same volume. Hence, there is less friction between silicone rubber

• to an intensification of friction and the generation of more charges. A similar trend is observed for VOC, as expected. Because of the mismatch between AC and DC systems a full-wave rectifier circuit was introduced to the setup. Figure 4a shows the voltage of different capacitors (2.2, 4.7, 10, and

Paper-based triboelectric nanogenerators and their applications: a review

• Jing Han,
• Nuo Xu,
• Yuchen Liang,
• Mei Ding,
• Junyi Zhai,
• Qijun Sun and
• Zhong Lin Wang

Beilstein J. Nanotechnol. 2021, 12, 151–171, doi:10.3762/bjnano.12.12

• moisture-retention capacity. This provides an efficient method to prepare paper electrodes for TENGs. Paper has also been proven to be a natural TENG friction layer. Due to that, it shows a tendency of easily losing electrons (i.e., electropositive) when contacting a material that can easily gain electrons

• (most common design in previous works) as a typical representative example, we further systematically analyze the working mechanism of the detailed charge-transfer process. Figure 2b elucidates the charge generation and the electron-transfer process at the friction interfaces (paper/the other dielectric

• negative charges) are induced by the same amount on the surfaces of the friction layers. As there is no electric potential at this stage, there is no electron transfer between the two conductive layers (Figure 2b-I). When the two friction layers start to separate along the vertical direction, opposite

Walking energy harvesting and self-powered tracking system based on triboelectric nanogenerators

• Mingliang Yao,
• Guangzhong Xie,
• Qichen Gong and
• Yuanjie Su

Beilstein J. Nanotechnol. 2020, 11, 1590–1595, doi:10.3762/bjnano.11.141

• area with the undulated electrode but also promotes the triboelectric charge density on the friction surface. The prepared u-TENGs are flexible, rugged, light, and small devices, as revealed in Figure 1c. It is worth noting that the application of the undulated electrode structure in this work is

Triboelectric nanogenerator based on Teflon/vitamin B1 powder for self-powered humidity sensing

• Liangyi Zhang,
• Huan Li,
• Yiyuan Xie,
• Jing Guo and
• Zhiyuan Zhu

Beilstein J. Nanotechnol. 2020, 11, 1394–1401, doi:10.3762/bjnano.11.123

• lubricant to make a friction nanogenerator. Due to its sustainability and flexibility, paper can be used as a substrate and supporting structure. The conductive electrode is made of copper foil, while the triboelectric pair is comprised of Teflon tape and vitamin B1 powder. The approximate values of the

Magnetohydrodynamic stagnation point on a Casson nanofluid flow over a radially stretching sheet

• Ganji Narender,
• Kamatam Govardhan and
• Gobburu Sreedhar Sarma

Beilstein J. Nanotechnol. 2020, 11, 1303–1315, doi:10.3762/bjnano.11.114

• written as The transformed boundary conditions are and the dimensionless parameters are defined as The formulas for the dimensional form of the skin-friction coefficient Cf, the Nusselt number Nu, and Sherwood number Sh, are given by and the formulas for τw, qw, and qm are The result of the transformation

• criteria for the shooting method is set as: in which ε is set as a very small positive number. In this work, ε is set as 10−5 whereas η∞ is set as 7. Results and Discussion In this section, the numerical results of the skin-friction coefficient, Nusselt and Sherwood numbers are listed in tables and shown

• ≤ 2.0, γ = 1.0, 1 ≤ Bi1 ≤ 2.0, and 1 ≤ Bi2 ≤ 2.0. Skin-friction coefficient, Nusselt and Sherwood numbers Prabhakar et al. [24] used a fourth-order Runge–Kutta method to obtain the numerical solution of the discussed model, whereas Attia [37] used the shooting technique and the computational software

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• the particle) and Brown relaxation (an external phenomenon driven by the rotation of the nanoparticle along the magnetic moment). Both internal and external sources of friction lead to a delay in the orientation of the particle magnetic moment in the direction of the applied magnetic field, thus

• nanoparticle i in the fluid environment [19] given as where mi is the mass of the i-th nanoparticle, is the linear speed of the i-th nanoparticle, is the resultant of the conservative forces acting on the i-th nanoparticle, αi,tr and αi,rot are the translational and rotational friction coefficients

Effect of magnetic field, heat generation and absorption on nanofluid flow over a nonlinear stretching sheet

• Santoshi Misra and
• Govardhan Kamatam

Beilstein J. Nanotechnol. 2020, 11, 976–990, doi:10.3762/bjnano.11.82

• the boundary layer, thus causing a reduction in its thickness for nanofluids. This is due to the fact that an increase in the slip parameter causes a reduction in the skin friction at the surface acting between the stretching sheet and the fluid flow, thus drastically decreasing the velocity gradient

• . Impact of ξ on θ(η) The temperature variation component, θ(η), increases with an increase in the slip parameter, ξ, which further leads to an increase in the fluid temperature, thus intensifying the thermal boundary layer thickness (Figure 3). An increase in the slip parameter causes friction at the

• slip parameter, ξ, at a given constant surface temperature. An increase in the slip parameter causes friction at the surface which, in turn, generates a frictional force allowing more fluid to flow passed the stretching sheet. This causes an increase in concentration distribution of the fluid as shown

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• particle moves along the potential in the presence of friction, the strength of which is characterized by α = ωp/ωc, where is the plasma frequency, ωc = 2eICRN/ℏ is the characteristic frequency, RN is the normal state resistance and C is the capacitance. The superconducting state of the JJ corresponds to