Enhancing mechanical properties of chitosan/PVA electrospun nanofibers: a comprehensive review

• Nur Areisman Mohd Salleh,
• Amalina Muhammad Afifi,
• Fathiah Mohamed Zuki and
• Hanna Sofia SalehHudin

Beilstein J. Nanotechnol. 2025, 16, 286–307, doi:10.3762/bjnano.16.22

• microscopy has been used to investigate morphology as well as the nanomechanical properties of individual fibers, including magnetization, friction, and mechanical strength [147]. These imaging techniques are critical for linking the mechanical behavior to the microstructure of the fibers. Based on fiber

Natural nanofibers embedded in the seed mucilage envelope: composite hydrogels with specific adhesive and frictional properties

• Agnieszka Kreitschitz and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2024, 15, 1603–1618, doi:10.3762/bjnano.15.126

• the mucilage envelope, primarily in the context of its structure and physical properties, as well as biological functions associated with these properties. Keywords: adhesion; cellulose; friction; hydrogel; mucilage envelope; seeds; Introduction The definition of hydrogels describes them as

• osmotic stress [4][5][6][10][24][25]. Depending on the hydration level, mucilage exhibits distinct physical properties, which are also connected with its biological functions. In a fully hydrated state, it demonstrates very low friction, important for example, in endozoochoric diaspore dispersal [26][27

• reformation, which may cause the mechanical collapse of the spatial structure. Frictional properties One of the important features of hydrogels [83][84][85][86][87] is their ability to decrease friction in contact. The frictional properties of hydrogels depend on their chemical composition [26][27][88][89

Hymenoptera and biomimetic surfaces: insights and innovations

• Vinicius Marques Lopez,
• Carlo Polidori and
• Rhainer Guillermo Ferreira

Beilstein J. Nanotechnol. 2024, 15, 1333–1352, doi:10.3762/bjnano.15.107

• of some species reduce friction and wear, inspiring the development of low-friction materials and coatings. By mimicking these natural textures, it is possible to create synthetic materials that exhibit similar friction-reducing properties, leading to significant advancements in mechanical efficiency

• and durability. For instance, low-friction coatings inspired by Hymenoptera cuticles can be applied to materials to reduce wear and tear, thereby enhancing performance, and extending the lifespan of the material. Surface roughness can have beneficial effects on the overall aerodynamic characteristics

• of particles [19]. Similarly, in the medical field, these coatings can be used on surgical instruments and prosthetics to minimize friction against biological tissues, reducing discomfort and improving the functionality of medical devices. Furthermore, in the field of electronics, low-friction

Interface properties of nanostructured carbon-coated biological implants: an overview

• Mattia Bartoli,
• Francesca Cardano,
• Erik Piatti,
• Stefania Lettieri,
• Andrea Fin and
• Alberto Tagliaferro

Beilstein J. Nanotechnol. 2024, 15, 1041–1053, doi:10.3762/bjnano.15.85

• ultrahigh-density poly(ethylene) reduced the friction coefficient more than any other tested nanostructured carbon coating. Nevertheless, surface wear remains an issue that needs to be solved in several key implants such as cardiovascular devices and joint replacements. NDs can play a crucial role because

• of the superior friction reduction achievable using thin ND films as reported by Blum and co-workers [142]. The authors sintered a 75 µm thick layer of NDs onto an aluminum alloy using a focused laser beam and reached a friction coefficient smaller than 0.2. Similar results can be obtained by using

Beyond biomimicry – next generation applications of bioinspired adhesives from microfluidics to composites

• Dan Sameoto

Beilstein J. Nanotechnol. 2024, 15, 965–976, doi:10.3762/bjnano.15.79

• film sheets combine under vacuum, offers more resilience and strength. However, vacuum jamming can present problems due to leaks, power consumption, noise from pumps, and the ultimate strength of the parts being limited by coefficients of friction and applied vacuum pressure. My interest in stiffness

• perfectly suited for biomimetic adhesives, as their coefficient of friction could be significantly higher than one, and our work on geckofluidics with rigid backing materials was already indicating similar capabilities. Once in contact with a smooth surface, isotropic biomimetic adhesives do not require

Effects of cutting tool geometry on material removal of a gradient nanograined CoCrNi medium entropy alloy

• Yu-Sheng Lu,
• Yu-Xuan Hung,
• Thi-Xuyen Bui and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2024, 15, 925–940, doi:10.3762/bjnano.15.76

• al. have shown that, as the grain size changes, the difference in friction coefficient with each cutting length is chaotic and does not follow the law of grain size increase [23]. The grain size affects the coefficient of friction in a rather complex way. Dislocation accumulation, lattice instability

• cutting stage. For the sample with a cutting-edge radius of 2.0 nm, the substrate is pushed with chip extrusion and friction, hence the oscillation of the normal force. Figure 12 compares the shear strain distribution in GNG CoCrNi MEAs for various cutting-edge radii during the cutting process. The

• , friction coefficients, and hardness values of some CoCrNi alloys from experimental works and MD simulations. In this work, the hardness was calculated using the following equation [46]: where Fmax and Ac are, respectively, the maximum indentation force and the contact area between the tool and the

The effect of age on the attachment ability of stick insects (Phasmatodea)

• Marie Grote,
• Stanislav N. Gorb and
• Thies H. Büscher

Beilstein J. Nanotechnol. 2024, 15, 867–883, doi:10.3762/bjnano.15.72

• Hennemann, 2023 and elucidate the age effects on the material and microstructure of the attachment apparatus. Attachment performance (adhesion and friction forces) on substrates with different roughnesses was compared between two different age groups, and the change of attachment performance was monitored

• extending over a larger time frame. Ageing effects on the morphology of the attachment pads and the autofluorescence of the cuticle were documented using light, scanning electron, and confocal laser scanning microscopy. The results show that both adhesion and friction forces decline with age. Deflation of

• area with the substrate. Keywords: adhesion; attachment pads; friction; locomotion; morphology; material properties; wear; Introduction Ageing inexorably affects most living organisms, does not exclude insects, and makes different organs or tissues susceptible to wear or fatigue of material [1

Investigation on drag reduction on rotating blade surfaces with microtextures

• Qinsong Zhu,
• Chen Zhang,
• Fuhang Yu and
• Yan Xu

Beilstein J. Nanotechnol. 2024, 15, 833–853, doi:10.3762/bjnano.15.70

• reduction effect of biomimetic microtextures can reduce friction and turbulence pulsation on blade surfaces, thus, improving the aerodynamic performance of blades [14]. The research on drag reduction of microtextures on blade surfaces can be traced back to the 1980s. In 1982, Walsh et al. [15] from NASA

• widths (w), spacings (s), and heights (h) of the microtextures were compared to determine the scale range with drag reduction. In the simulation setup, the initial conditions and the flow domain are consistent with the single flow domain of the blade. The coefficient of friction and the DRR from the

• %. Hence, the flow field of the smooth blade surface at span = 0.5 is further analyzed. Table 5 presents the resistance results of the smooth blade, where the total drag (Td) in the direction of airflow was divided into pressure drag (Pd) and friction drag (Fd). The primary impact of the microtextures is

Functional fibrillar interfaces: Biological hair as inspiration across scales

• Guillermo J. Amador,
• Brett Klaassen van Oorschot,
• Caiying Liao,
• Jianing Wu and
• Da Wei

Beilstein J. Nanotechnol. 2024, 15, 664–677, doi:10.3762/bjnano.15.55

• present [57], or intermolecular interactions, when no adhesive fluid is present [58]. In addition to adhesive forces that enable inverted climbing, the hairs can also generate friction forces whenever the animals climb on vertical surfaces [59]. For geckos, these adhesive hairs are referred to as setae

• be used by males to attach securely to females when mating [59]. Both males and females possess adhesive hairs with spatula-shaped and sharp tips. The spatula-shaped tips enable reversibility of adhesion, while the sharp-tipped hairs are used for generating friction [59]. For microorganisms, while

• [21][22]. Burrowing The use of hairs to generate frictional forces is not unique to animals that climb. Hair-like setae on the skin of earthworms aid in burrowing by increasing friction and providing anisotropic anchoring [65][66][67]. When burrowing, the earthworm mainly uses cavity expansion to

Comparative analysis of the ultrastructure and adhesive secretion pathways of different smooth attachment pads of the stick insect Medauroidea extradentata (Phasmatodea)

• Julian Thomas,
• Stanislav N. Gorb and
• Thies H. Büscher

Beilstein J. Nanotechnol. 2024, 15, 612–630, doi:10.3762/bjnano.15.52

• long intrigued scientists, prompting extensive research on the functional morphology of attachment pads. In stick insects, attachment and locomotion are facilitated by two distinct types of smooth cuticular attachment pads: the primary adhesion force-generating arolium and the friction force-generating

• the material composition of attachment pads and the distribution process of the adhesive secretion can potentially aid in the development of more effective artificial attachment systems. Keywords: adhesion; arolium; biomechanics; euplantulae; friction; functional morphology; tarsal secretion

• ; Introduction Throughout their evolutionary timeline, insects evolved various surfaces interacting with the environment. These include friction-based adhesive organs, which are essential for locomotion by generating frictional and adhesive forces [1][2][3][4]. Two morphologically different friction-based

Heat-induced morphological changes in silver nanowires deposited on a patterned silicon substrate

• Elyad Damerchi,
• Sven Oras,
• Edgars Butanovs,
• Allar Liivlaid,
• Mikk Antsov,
• Boris Polyakov,
• Annamarija Trausa,
• Veronika Zadin,
• Andreas Kyritsakis,
• Loïc Vidal,
• Karine Mougin,
• Siim Pikker and
• Sergei Vlassov

Beilstein J. Nanotechnol. 2024, 15, 435–446, doi:10.3762/bjnano.15.39

• exceed the ultimate strength of Ag NWs. Based on these facts, we expect that the thermal expansion of Ag NWs will compete with friction forces between the NWs and Si substrate, causing significant mechanical stresses inside the NWs, especially at the interface between the two materials. This may serve as

Insect attachment on waxy plant surfaces: the effect of pad contamination by different waxes

• Elena V. Gorb and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2024, 15, 385–395, doi:10.3762/bjnano.15.35

• substrate pulling the hair for ca. 30 s, while the friction (traction) force thus produced by the moving insect was registered. Since the insects walked parallel to the measurement axis of the sensor, the recorded force corresponded to the total traction force. Force–time curves obtained were used to

Determination of the radii of coated and uncoated silicon AFM sharp tips using a height calibration standard grating and a nonlinear regression function

• Perawat Boonpuek and
• Jonathan R. Felts

Beilstein J. Nanotechnol. 2023, 14, 1200–1207, doi:10.3762/bjnano.14.99

• nanostructured materials, for example, graphene, carbon nanotubes, nanoscale semiconductors, biomaterials, and molecules. Mechanical properties such as surface stiffness, adhesion, friction, electrostatics, and electrowetting can be measured [1][2][3][4]. In contact mode scanning, the contact area between the

• force curves with contact mechanics models and extracting the adhesion and friction forces [5][6]. If we do not know the exact value of the tip radius, the sample image with the observation of scanning frequency and the calculation results are not accurate. This indicates that the measurement results

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

• -containing case. Results of viscosity measurement The literature indicates that the use of nanolubricants reduces power consumption and the coefficient of friction compared to the use of pure lubricant [43]. However, the addition of nanoparticles to the lubricant above the optimum mass fraction had a

A wearable nanoscale heart sound sensor based on P(VDF-TrFE)/ZnO/GR and its application in cardiac disease detection

• Yi Luo,
• Jian Liu,
• Jiachang Zhang,
• Yu Xiao,
• Ying Wu and
• Zhidong Zhao

Beilstein J. Nanotechnol. 2023, 14, 819–833, doi:10.3762/bjnano.14.67

• advancement in wearable electronic devices within the healthcare field, leading to several noteworthy breakthroughs. For instance, D. Wan et al. [11] presented a groundbreaking development in the form of a flexible wearable friction patch. This innovative patch consists of a dual-layer PDMS membrane infused

• with hydrogel. It harnesses the energy generated from bodily movements and utilizes it to create an electric field between the friction patch and the surrounding body tissues, thereby promoting the expedited healing of wounds. Poly(vinylidene fluoride–trifluoroethylene) (P(VDF-TrFE)) is a piezoelectric

Current-induced mechanical torque in chiral molecular rotors

• Richard Korytár and
• Ferdinand Evers

Beilstein J. Nanotechnol. 2023, 14, 711–721, doi:10.3762/bjnano.14.57

• different values of ρF and μ in Figure 7. The data collapses on a single curve, which saturates in the large impact velocity limit. Discussion First, we discuss some straightforward extensions of our model that account for (1) friction and (2) temperature effects. Then, we discuss the prospective

• applications as a switch and for information storage. The role of quantum effects is discussed at the end. Our model can be straightforwardly extended to include a friction term acting on the coordinate ϑ. Such friction can originate at the bearings of the rotor (at the entrance and exit of the path in our

• case). The projectile also experiences friction. Due to conservation laws, the loss of the angular momentum of the projectile is compensated by an increase of . Therefore, this friction is included in our formulation. Our results are valid when thermal fluctuations are small, that is, kBT ≪ ΔV. To

Suspension feeding in Copepoda (Crustacea) – a numerical model of setae acting in concert

• Alexander E. Filippov,
• Wencke Krings and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2023, 14, 603–615, doi:10.3762/bjnano.14.50

• liquid by a “mutual friction” between the particles and setae, which aims to reduce the difference between the particle and setae velocity at relatively short distances according to simple factors in the dynamic equations of motion. The particles move in an “empty space”, but interact with the flows

• potential (exponentially depending on the distance) interaction (interaction caused by a mutual friction, which tends to reduce a difference between velocities). The appropriate force from the setae acting on every particle is represented as a combination of the following velocity- and distance-dependent

Antimicrobial and mechanical properties of functionalized textile by nanoarchitectured photoinduced Ag@polymer coating

• Jessica Plé,
• Marine Dabert,
• Helene Lecoq,
• Sophie Hellé,
• Lydie Ploux and
• Lavinia Balan

Beilstein J. Nanotechnol. 2023, 14, 95–109, doi:10.3762/bjnano.14.11

• component are also presented (Figure 7b). Before abrasion, the Ag@PEG600DA coating is highly reflective, with a total reflectance value of 97% at 700 nm, of which 52% comes from the diffuse component. The applied friction seems to polish the surface, increasing its mirror-like aspect. After 500 cycles, the

• total reflectance increased significantly between 400 and 580 nm, while dropping slightly (10%) in the 580–1000 nm range. The diffuse reflectance effectively decreased from 52 to 20% at 700 nm. Indeed, friction causes a localized rise in temperature between particles, which promotes a reduction in

• surface roughness, as can be seen in the SEM images (Figure 7c). Consequently, the diffuse reflectivity drops in favor of the specular reflectance. The particles are no longer simply juxtaposed but form a continuous silver layer, especially after 1000 friction cycles. The characteristic silver plasmon

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

• between water and a solid surface might serve as friction reduction agents, fouling protectors, corrosion protectors or for other applications, such as sensors [11][12][13][14]. Biological examples for such air retaining surfaces with most stable and persistent air layers were found on the floating ferns

• function for biomimetic air retaining surfaces is drag reduction. If an air layer is mounted between a solid surface and water flowing over this surface, the air layer serves as slip agent [26][27][28]. Such a drag reducing coverage allows significant friction reduction (up to 30%) in applications, where

Bending and punching characteristics of aluminum sheets using the quasi-continuum method

• Man-Ping Chang,
• Shang-Jui Lin and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2022, 13, 1303–1315, doi:10.3762/bjnano.13.108

• strength at a specific structural orientation [51]. Besides, Tran et al. studied the friction and scratch characteristics of pure aluminum by the QC method. The bump width to the bump pitch (W/P) value, scratch depth, surface roughness, and indenter radius were set as variables in order to explore the

• friction behaviors of different models [52]. Moreover, the QC method based on the embedded-atom method (EAM) potential was adopted to observe the fatigue crack growth and expansion characteristics of single-crystal metals under cyclic loading processes. The results showed that after compressive or shear

• of the coupled regions [54]. Results and Discussion In this section, the QC method was used to explore the effects of different crystal orientations, workpiece thickness, clearance, and taper angle on the nano-punching process. The friction characteristic of interface and residual flash phenomena

Interaction between honeybee mandibles and propolis

• Leonie Saccardi,
• Franz Brümmer,
• Jonas Schiebl,
• Oliver Schwarz,
• Alexander Kovalev and
• Stanislav Gorb

Beilstein J. Nanotechnol. 2022, 13, 958–974, doi:10.3762/bjnano.13.84

• morphology of the mandibles, as all examined mandibles had this characteristic. Anisotropic structures are also present on other animals such as snakes and were proposed to support anisotropic properties, for example, anisotropic friction [34]. The scales on bee mandibles are mostly oriented towards the apex

Micro-structures, nanomechanical properties and flight performance of three beetles with different folding ratios

• Jiyu Sun,
• Pengpeng Li,
• Yongwei Yan,
• Fa Song,
• Nuo Xu and
• Zhijun Zhang

Beilstein J. Nanotechnol. 2022, 13, 845–856, doi:10.3762/bjnano.13.75

• induced drag Dind, profile drag Dpro, and parasite drag Dpar. Dind represents the cost of generating lift, Dpro is the drag of the wings and Dpar is due to skin friction and the drag from the body form [45]. It was found that the wingspan b and Sw of the hind wings decrease simultaneously when passive

Temperature and chemical effects on the interfacial energy between a Ga–In–Sn eutectic liquid alloy and nanoscopic asperities

• Yujin Han,
• Pierre-Marie Thebault,
• Corentin Audes,
• Xuelin Wang,
• Haiwoong Park,
• Jian-Zhong Jiang and
• Arnaud Caron

Beilstein J. Nanotechnol. 2022, 13, 817–827, doi:10.3762/bjnano.13.72

• and corresponds to friction. In our case, we attribute the observed hysteresis of the lateral force to the resistance to pull and drag a meniscus at the tip–metallic liquid interface. In principle, this resistance corresponds to the interfacial tension of the tip and metallic liquid. The occurrence of

Hierachical epicuticular wax coverage on leaves of Deschampsia antarctica as a possible adaptation to severe environmental conditions

• Elena V. Gorb,
• Iryna A. Kozeretska and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2022, 13, 807–816, doi:10.3762/bjnano.13.71

• /friction on the nanoscale rough surface is rather low [46][47]. Conclusion A cryo-SEM examination of the vegetative (leaf blade and ligule) and generative (pedicel and outer glume) organs in D. antarctica revealed a prominent epicuticular wax coverage on surfaces of both vegetative organs studied. Whereas

Fabrication and testing of polymer microneedles for transdermal drug delivery

• Vahid Ebrahiminejad,
• Zahra Faraji Rad,
• Philip D. Prewett and
• Graham J. Davies

Beilstein J. Nanotechnol. 2022, 13, 629–640, doi:10.3762/bjnano.13.55

• algorithm was used to create fine elements at the tip of the MNs. The coefficient of friction between the contact surfaces was set to 0.42 [29]. Upon MN penetration, with a constant impact speed of 4.5 m/s, the force-displacement data were recorded to estimate the insertion force. To enable the skin