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

• modulus (or elastic modulus) is a measurement of elasticity, which describes the stiffness of nanofibers and is calculated as the ratio of stress to strain in the elastic deformation region, which is the slope of the initial linear region of the stress–strain curve. Elongation at break measures the extent

• as the additional parameter [140]. The presence of chitosan in PVA membranes is expected to increase the storage modulus because of the higher stiffness of chitosan chains compared to PVA chains, as reported from DMA tests by Parparita and coworkers [141]. Koosha et al. [59] measured the dynamic

• between polymer chains, resulting in structures that are stable under deformation, exhibiting high stiffness and mechanical elasticity. This process is often facilitated by agents such as glutaraldehyde [174], epichlorohydrin, genipin, and citric acid [164]. Physical cross-linking involves non-covalent

Advanced atomic force microscopy techniques V

• Philipp Rahe,
• Ilko Bald,
• Nadine Hauptmann,
• Regina Hoffmann-Vogel,
• Harry Mönig and
• Michael Reichling

Beilstein J. Nanotechnol. 2025, 16, 54–56, doi:10.3762/bjnano.16.6

• accurate knowledge of the quartz cantilever stiffness, the authors develop a method to quantify the stiffness based on thermal noise measurements and numerical simulation. Calibrated measurements of conductivity and resistivity are the focus of the contribution by Piquemal et al. [3]. A particular

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

• friction of mucilage just after hydration. In time series of measurements, the friction increased. The water loss from the mucilage caused an increase of its stiffness and adhesive properties [26]. The decreasing hydration level and the increasing viscosity of flax mucilage play an important role in the

Strain-induced bandgap engineering in 2D ψ-graphene materials: a first-principles study

• Kamal Kumar,
• Nora H. de Leeuw,
• Jost Adam and
• Abhishek Kumar Mishra

Beilstein J. Nanotechnol. 2024, 15, 1440–1452, doi:10.3762/bjnano.15.116

• remaining C–C bond lengths fluctuate as the applied strain level increases or decreases. It is known that the in-plane stiffness of ψ-graphene is higher than that of penta-graphene and is comparable to that of graphene [16]. Therefore, it can resist compressive strain (negative strain) in its lattice plane

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

• structural stiffness [104]. Research on biological membranes, inspired by the superior structures of insect wings, holds potential for advancements in various sectors, including medical, construction, aviation, and automotive industries [104][105][106][107][108]. Research on hymenopteran wings remains

New design of operational MEMS bridges for measurements of properties of FEBID-based nanostructures

• Bartosz Pruchnik,
• Krzysztof Kwoka,
• Ewelina Gacka,
• Dominik Badura,
• Piotr Kunicki,
• Andrzej Sierakowski,
• Paweł Janus,
• Tomasz Piasecki and
• Teodor Gotszalk

Beilstein J. Nanotechnol. 2024, 15, 1273–1282, doi:10.3762/bjnano.15.103

• . The silicon edges under the opMEMS bridge bases were defined to be vertical and precisely located, thanks to the lattice orientation. The opMEMS were 600 μm long, 100 μm wide, and 80 nm thick, with 40 nm of silicon nitride body and 40 nm of platinum paths on top. To reduce the stiffness of the opMEMS

• analyser to assess the properties of the active device. The measured level of vibration of the MEMS bridge at a known temperature allows its stiffness to be determined with an accuracy of 5% [38]. First, the thermomechanical noise of the structure vibration was measured, then the displacement of the

• spectral analysis of vibrations [49]. The thermomechanical noise analysis approximates the bridge as a simple harmonic oscillator with one DOF, as has been used for determining the spring constant of AFM cantilevers [50]. This approach provides an approximation for the stiffness k in terms of the measured

Functional morphology of cleaning devices in the damselfly Ischnura elegans (Odonata, Coenagrionidae)

• Silvana Piersanti,
• Gianandrea Salerno,
• Wencke Krings,
• Stanislav Gorb and
• Manuela Rebora

Beilstein J. Nanotechnol. 2024, 15, 1260–1272, doi:10.3762/bjnano.15.102

• nanoindentation tests, discovered that the tibial comb of honeybees exhibits a resilin gradient with a stiffness variation spanning nearly two orders of magnitude, ranging from approximately 25 MPa at the tip to around 645 MPa at the base. This gradient enhances the catapult effect, allowing the comb to produce

• increased inertia that counteracts the initially dominant adhesion, effectively dislodging attached pollen and dust. The same authors also developed an elastomeric bioinspired stiffness-gradient catapult and demonstrated its potential in practical applications, thus confirming that studies on the functional

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

• degree of controllability or even its ability to self-support under gravitational loads; thus, there is a major interest in stiffness-tunable materials for soft robotic systems [15]. This stiffness tuning in many cases relies on the temporary bonding of composite layers or materials to change effective

• stiffness. While soft robotics have shown a need for stiffness-tunable materials, the ability for composites in and of themselves to be reversibly bonded potentially opens up a far greater industrial impact and applications in adaptable, smart materials. Even improved sustainability could be achieved if

• laminates and composites could be reformed and reused. The secret to improve use cases of reversible adhesives and to improve applications in the above three subfields is to use biomimetic materials to manufacture composites which, in turn, have the capacity to change their stiffness, shape, or other

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

• increased stiffness are accompanied by the decreased ability to climb an incline [5][16]. Zhou et al. [17] found stiffer and darker “scars” on the pads of aged cockroaches, most likely due to accumulated damage, resulting in the pads not being as compliant as in younger cockroaches. Slifer [18] made similar

• stiffness of the cuticle of these organs and the internal pressure are important for the functionality and likely susceptible to decay during ageing [42][43]. We investigated the change in attachment ability and tarsal morphology in the species Sungaya aeta Hennemann, 2023 (Heteropterygidae). Members of

• surface in younger adult individuals. This effect vanished for older adult animals, as attachment forces became more similar on all three substrates. No change of nub morphology was observed in older animals (Figure 7G,I), but a change of stiffness of the nubs could potentially affect their functionality

Elastic modulus of β-Ga₂O₃ nanowires measured by resonance and three-point bending techniques

• Annamarija Trausa,
• Sven Oras,
• Sergei Vlassov,
• Mikk Antsov,
• Tauno Tiirats,
• Andreas Kyritsakis,
• Boris Polyakov and
• Edgars Butanovs

Beilstein J. Nanotechnol. 2024, 15, 704–712, doi:10.3762/bjnano.15.58

• the length of the NW. Three-point bending tests Three-point bending tests were performed by AFM (Dimension Edge, Bruker) using noncontact mode cantilevers with nominal stiffness of 42 N/m (NCHR-50, Nanosensors, Figure 6b). The NW lengths and widths for three-point bending were measured by SEM (Nova

Enhancing higher-order modal response in multifrequency atomic force microscopy with a coupled cantilever system

• Wendong Sun,
• Jianqiang Qian,
• Yingzi Li,
• Yanan Chen,
• Zhipeng Dou,
• Rui Lin,
• Peng Cheng,
• Xiaodong Gao,
• Quan Yuan and
• Yifan Hu

Beilstein J. Nanotechnol. 2024, 15, 694–703, doi:10.3762/bjnano.15.57

• . More details about the derivation process can be found in [19]. The final result for the transfer function G of the infinite product expansion is obtained as: where s is the (complex) Laplace variable, and m is the mass per unit length. EI and c are the flexural stiffness and the damping coefficient

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

• [113]. Intriguingly, even after attachment, having motile flagella still matters for the cell as it appears to enable sensing of substrate stiffness [114]. In addition to flagella, other hairs of E. coli include the type-I pili (frimbriae) and type-IV pili [113]. Collaboration between these hairs also

• –channel protein complex may provide mechanical gating to sense deflections of the mastigonemes caused by fluid flow [112]. Additionally, for bacteria, E. coli, their passive flagella have been linked to sensing the material stiffness of surfaces they attach to [114]. Clusters of hairs, or hair plates, on

Stiffness calibration of qPlus sensors at low temperature through thermal noise measurements

• Laurent Nony,
• Sylvain Clair,
• Daniel Uehli,
• Aitziber Herrero,
• Jean-Marc Themlin,
• Andrea Campos,
• Franck Para,
• Alessandro Pioda and
• Christian Loppacher

Beilstein J. Nanotechnol. 2024, 15, 580–602, doi:10.3762/bjnano.15.50

• to perform frequency shift spectroscopy to quantitatively evaluate the tip–sample interaction forces and potentials above individual atoms or molecules. The stiffness of the probe, k, is then required to perform the frequency shift-to-force conversion. However, this quantity is generally known with

• little precision. An accurate stiffness calibration is therefore mandatory if accurate force measurements are targeted. In nc-AFM, the probe may either be a silicon cantilever, a quartz tuning fork (QTF), or a length extensional resonator (LER). When used in ultrahigh vacuum (UHV) and at low temperature

• stiffness calibration of a particular type of qPlus sensor in UHV and at 9.8 K by means of thermal noise measurements. The stiffness calibration of such high-k sensors, featuring high quality factors (Q) as well, requires to master both the acquisition parameters and the data post-processing. Our approach

Modulated critical currents of spin-transfer torque-induced resistance changes in NiCu/Cu multilayered nanowires

• Mengqi Fu,
• Roman Hartmann,
• Julian Braun,
• Sergej Andreev,
• Torsten Pietsch and
• Elke Scheer

Beilstein J. Nanotechnol. 2024, 15, 360–366, doi:10.3762/bjnano.15.32

• stiffness, the dipolar stray field, and the anisotropy field caused by the spin–orbit interaction [34]. Since the magnetization of layer 1 () and layer 3 () are both parallel to the applied magnetic field (here: positive), the exchange stiffness as well as the dipolar stray field on layer 2 point in the

Controllable physicochemical properties of WO_x thin films grown under glancing angle

• Rupam Mandal,
• Aparajita Mandal,
• Alapan Dutta,
• Rengasamy Sivakumar,
• Sanjeev Kumar Srivastava and
• Tapobrata Som

Beilstein J. Nanotechnol. 2024, 15, 350–359, doi:10.3762/bjnano.15.31

• measurements, a conductive tip (Ti/Pt coated) having a resonance frequency of approx. 70 kHz, a stiffness of approx. 2 N·m−1, and a radius of curvature of approx. 30 nm was used for KPFM measurements. To examine the uniformity in work function values of each film, different regions on the sample surface were

Design, fabrication, and characterization of kinetic-inductive force sensors for scanning probe applications

• August K. Roos,
• Ermes Scarano,
• Elisabet K. Arvidsson,
• Erik Holmgren and
• David B. Haviland

Beilstein J. Nanotechnol. 2024, 15, 242–255, doi:10.3762/bjnano.15.23

• transducer, converting the tip–surface force to changes in its sinusoidal motion as the tip oscillates above the surface with amplitude A ≃ 1 nm, the typical range of tip–surface forces. Furthermore, we desire that the stiffness of the mechanical mode is k ≃ 100 N/m, the typical change in tip–surface force

• fabricated on the same Si-N layer. By increasing the thickness of the Si-N plate, we increase the surface strain for the same curvature of the cantilever, giving larger values of which also increases the stiffness of the bending mode. We can compensate for the latter by increasing the length and reducing

Exploring disorder correlations in superconducting systems: spectroscopic insights and matrix element effects

• Vyacheslav D. Neverov,
• Alexander E. Lukyanov,
• Andrey V. Krasavin,
• Alexei Vagov,
• Boris G. Lvov and
• Mihail D. Croitoru

Beilstein J. Nanotechnol. 2024, 15, 199–206, doi:10.3762/bjnano.15.19

• order parameter, and the superfluid stiffness, were elucidated in a prior study [49]. In the present study, we further explore the effects caused by correlated disorder and specifically elucidate the results related to the quasi-particle DOS, an aspect that has so far been overlooked in our earlier

Modification of graphene oxide and its effect on properties of natural rubber/graphene oxide nanocomposites

• Nghiem Thi Thuong,
• Le Dinh Quang,
• Vu Quoc Cuong,
• Cao Hong Ha,
• Nguyen Ba Lam and
• Seiichi Kawahara

Beilstein J. Nanotechnol. 2024, 15, 168–179, doi:10.3762/bjnano.15.16

• particles on the GO surface, providing the stiffness for DPNR/GO-VTES. Furthermore, tensile strength for DPNR/GO-VTES(a) was slightly higher than that of DPNR/GO-VTES(b), which suggested that GO-VTES(a) may have better interaction with NR than GO-VTES(b). The silica particles on the GO layer may hinder the

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

• AFM tip and the sample, which depends on the tip radius, defines how accurately the AFM tip determines those properties and the shape of fabricated micro- and nanostructures. The contact radius of the tip is a key variable for calculating the stiffness and Young’s modulus of the material by fitting

Spatial variations of conductivity of self-assembled monolayers of dodecanethiol on Au/mica and Au/Si substrates

• Julian Skolaut,
• Jędrzej Tepper,
• Federica Galli,
• Wulf Wulfhekel and
• Jan M. van Ruitenbeek

Beilstein J. Nanotechnol. 2023, 14, 1169–1177, doi:10.3762/bjnano.14.97

• applied method uses conductive atomic force microscopy (CAFM). In this technique, a conductive probe is used in an AFM, which allows for imaging the surface topography (and other characteristics such as adhesion and stiffness) with lateral resolution while simultaneously being able to measure current

Elasticity, an often-overseen parameter in the development of nanoscale drug delivery systems

• Agnes-Valencia Weiss and
• Marc Schneider

Beilstein J. Nanotechnol. 2023, 14, 1149–1156, doi:10.3762/bjnano.14.95

• properties of drug carriers. Keywords: atomic force microscopy; drug delivery; elasticity; mechanical properties; nanomedicine; nanoparticles; stiffness measurement; tissue/body distribution; Introduction Drug delivery systems are developed with the aim to transport a given drug to the site of action

• properties of nanoparticles, it nearly impossible to compare studies from different labs and pick a value to aim for during the development of a drug delivery system. This is due to the variety of possibilities to examine and express the mechanical properties of these systems (e.g., stiffness, elasticity

• particles showed better cellular uptake if no mucus layer was present. In contrast to this, the cellular uptake for semielastic particles was not significantly affected by the presence of a mucus layer [38]. Liposomes with PLGA cores were used by Yu et al. to increase the stiffness in combination with

Spatial mapping of photovoltage and light-induced displacement of on-chip coupled piezo/photodiodes by Kelvin probe force microscopy under modulated illumination

• Zeinab Eftekhari,
• Nasim Rezaei,
• Hidde Stokkel,
• Jian-Yao Zheng,
• Andrea Cerreta,
• Ilka Hermes,
• Minh Nguyen,
• Guus Rijnders and
• Rebecca Saive

Beilstein J. Nanotechnol. 2023, 14, 1059–1067, doi:10.3762/bjnano.14.87

• -right corner of each color map. The expected bulging shape is observed for samples B and C shown in Figure 4b and c, respectively. The smallest sample (D) nonetheless shows a relatively uniform displacement, which can arise from the increased stiffness of the membrane as a result of its minuscule

Exploring internal structures and properties of terpolymer fibers via real-space characterizations

• Michael R. Roenbeck and
• Kenneth E. Strawhecker

Beilstein J. Nanotechnol. 2023, 14, 1004–1017, doi:10.3762/bjnano.14.83

• nano- and microscale topography, stiffness, and transverse elastic modulus (ET) maps of internal structural features and local mechanical responses in real space. (See the Experimental section for additional details.) As Technora® has often been compared to Kevlar® K29 fibers, we focus further on

• ®, both the topography and stiffness maps (Figure 2) revealed a consistent microstructure across the fiber diameter at this length scale. Complementing topography and stiffness maps, lateral line profiles (e.g., dashed line, Figure 2a) quantified both topography and stiffness variations across the

• diameter. Topography and stiffness (Figure 2c) were remarkably uniform across the diameter as well. Only two notable features deviate from our consistent topography and stiffness measurements: (i) slopes from the outer edges inward and (ii) a sudden jump at a lateral position of ca. 5 μm. It should be

Metal-organic framework-based nanomaterials as opto-electrochemical sensors for the detection of antibiotics and hormones: A review

• Akeem Adeyemi Oladipo,
• Saba Derakhshan Oskouei and
• Mustafa Gazi

Beilstein J. Nanotechnol. 2023, 14, 631–673, doi:10.3762/bjnano.14.52

• linkers have been used, many of which contain rigid backbones that have been substituted with multiple carboxylate groups for metal coordination. As linkers in MOFs, organic compounds with fused π rings and strong conjugation are frequently used. Due to their stiffness, they are frequently both very

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

• of the process, which allows us to make some conclusions about the efficiency of the feeding process at different properties of the setae. The segments were provided with longitudinal (K∥) and transverse (K⟂) stiffness, K∥ = K⟂. The transverse stiffness tends to hold the angle between the neighboring

• segments close to 180°. According to the goals of this study, we varied the stiffness from segment to segment depending on the hypothetical particular structure. A deformation of the setae produced elastic forces proportional to the seta stiffness. The forces were described by the following equations (see