Wet-spinning of magneto-responsive helical chitosan microfibers

• Dorothea Brüggemann,
• Johanna Michel,
• Naiana Suter,
• Matheus Grande de Aguiar and
• Michael Maas

Beilstein J. Nanotechnol. 2020, 11, 991–999, doi:10.3762/bjnano.11.83

• fiber was measured in an optical microscope (SENSOFAR PLl 2300, Nikon, Tokyo, Japan). Thus, the stress–strain relation of each individual fiber could be determined by taking into account the gauge length of 25 mm. (A, B) Shear viscosity and shear stress of bare chitosan solutions (black lines) and

Extracting viscoelastic material parameters using an atomic force microscope and static force spectroscopy

• Cameron H. Parvini,
• M. A. S. R. Saadi and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 922–937, doi:10.3762/bjnano.11.77

• for a given stress or strain excitation. The mechanical-equivalent approach is simple to explain, but can require more assumptions and some additional knowledge of the Laplace transform to derive analytical stress–strain relationships. Alternatively, continuum mechanics can be used to create more

• ] recently formulated a generalized solution to the physical contact problem in AFM-SFS experiments, particularly for cases where the sample is viscoelastic. The approach is also capable of being adapted to any linear viscoelastic stress–strain model. Their method utilized a theoretical basis for

• then subsequently removed. For example, one method involves hanging weights from a material for some time, then removing the weights and allowing the material to recover. A strain gage or displacement sensor captures the deformation occurring during both phases, and the data is used for fitting. The

Light–matter interactions in two-dimensional layered WSe₂ for gauging evolution of phonon dynamics

• Avra S. Bandyopadhyay,
• Chandan Biswas and
• Anupama B. Kaul

Beilstein J. Nanotechnol. 2020, 11, 782–797, doi:10.3762/bjnano.11.63

• decreased interfacial defect density and built-in strain on sapphire that reduces the electron–phonon interaction in the material [30]. The value of τ obtained in our study is also comparable to what has been reported for τ in 1L CVD grown WSe2 (≈0.76 ps) [30], bilayer CVD grown WSe2 (≈2.4 ps) [29], MoS2

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• criteria for spin–photon-phonon entanglement distribution are high electron spin coherence time T2 (approaching T2 spin-lattice relaxation time) and strain and electrical control of the spin transition and optical transition resonances. The key requirements can be restrictive depending on the applications

• energy in each group (±20 meV) was attributed to variations of the strain in the h-BN matrix, as well as photo-conversion to a dark state that may be responsible for the blinking. Only 5% of the emitters were photostable. The photo-dynamics indicates the presence of a metastable state (3-level system

• . However, the PL is not sufficient to univocally identify the type of defects, while the correlation with material properties and SPEs should be performed. In [114] h-BN the quantum emission was correlated with the material’s local strain using a combination of PL, nanobeam electron diffraction, scanning

Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• itself is highly sensitive to the type and position of substitutional defects, the intentional introduction of such defects can be utilized to design nanoscale RTDs with desired NDR characteristic and RTD-based strain or pressure sensors with improved sensitivity. (a) Schematic representation of the

Electromigration-induced directional steps towards the formation of single atomic Ag contacts

• Atasi Chatterjee,
• Christoph Tegenkamp and
• Herbert Pfnür

Beilstein J. Nanotechnol. 2020, 11, 680–687, doi:10.3762/bjnano.11.55

• materials like Ag, grain boundaries occur mostly because of the different orientation of nanocrystals. Since the elastic strain energy strongly increases with angular misfit, small-angle grain boundaries are the most likely ones. Thus, most contact areas are not far from (stepped) high-symmetry crystal

• section and its variation by EM is considered. Thus, deviations due to unknown step densities and local strain are ignored when considering only high-symmetry directions of the interface, as we do in the following. Figure 3 represents the FT of the conductance histogram in Figure 2 of bow-tie structures

A novel dry-blending method to reduce the coefficient of thermal expansion of polymer templates for OTFT electrodes

• Xiangdong Ye,
• Bo Tian,
• Yuxuan Guo,
• Fan Fan and
• Anjiang Cai

Beilstein J. Nanotechnol. 2020, 11, 671–677, doi:10.3762/bjnano.11.53

• (TMA, Q400, TA Instruments, New Castle, DE, USA). Five specimens per group with dimensions 20 × 2 × 1 mm were prepared and the average strain was calculated. During the test, the temperature was increased from 20 to 200 °C at a rate of 20 °C/min. The CTE of the PDMS/SiO2 composite template was

• ]), ρn is the density of PDMS (965 kg·m−3 [20]), and υ is the volume fraction of the SiO2 nanoparticles (65.4 vol %). The calculated weight fraction of the SiO2 nanoparticles filled via dry blending is 83.8 wt %. CTE of the PDMS/SiO2 composite template The strain–temperature curves of the PDMS/SiO2

• also shown in Figure 4. The curves for 0–20 wt % of SiO2 nanoparticles in Figure 4 are the strain–temperature curves for the PDMS/SiO2 composite template prepared via wet blending, while the curve for 83.8 wt % is the strain–temperature curve for the template prepared via dry blending. The latter curve

Observation of unexpected uniaxial magnetic anisotropy in La_2/3Sr_1/3MnO₃ films by a BaTiO₃ overlayer in an artificial multiferroic bilayer

• John E. Ordóñez,
• Lorena Marín,
• Luis A. Rodríguez,
• Pedro A. Algarabel,
• José A. Pardo,
• Roger Guzmán,
• Luis Morellón,
• César Magén,
• Etienne Snoeck,
• María E. Gómez and
• Manuel R. Ibarra

Beilstein J. Nanotechnol. 2020, 11, 651–661, doi:10.3762/bjnano.11.51

• results indicate that the BaTiO3 layer induces an additional strain in the La2/3Sr1/3MnO3 layers close to their common interface. The presence of BaTiO3 on the surface of tensile-strained La2/3Sr1/3MnO3 films transforms the in-plane biaxial magnetic anisotropy present in the single layer into an in-plane

• uniaxial magnetic anisotropy. Our experimental evidence suggests that this change in the magnetic anisotropy only occurs in tensile-strained La2/3Sr1/3MnO3 film and is favored by an additional strain on the La2/3Sr1/3MnO3 layer promoted by the BaTiO3 film. These findings reveal an additional mechanism that

• alters the magnetic behavior of the ferromagnetic layer, and consequently, deserves further in-depth research to determine how it can modify the magnetoelectric coupling of this hybrid multiferroic system. Keywords: artificial multiferroic system; BaTiO3; interface-induced strain; La2/3Sr1/3MnO3

Silver-decorated gel-shell nanobeads: physicochemical characterization and evaluation of antibacterial properties

• Marta Bartel,
• Katarzyna Markowska,
• Marcin Strawski,
• Krystyna Wolska and
• Maciej Mazur

Beilstein J. Nanotechnol. 2020, 11, 620–630, doi:10.3762/bjnano.11.49

• antimicrobial activity. The MIC values for all of the tested bacterial strains are in the range from 0.76 to 1.14 µg/mL. The least susceptible bacterial strain was gram-positive S. aureus, for which the growth was inhibited at the concentration of 1.14 µg/mL. This result is consistent with previous reports on

• exposed surface and the retardation of the nanoparticle diffusion caused by aggregation [48]. Some species develop less complicated biofilm structures or even are not capable to form biofilms. The S. epidermidis strain used in our experiments probably does not form complex biofilm structures, as the three

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• , Institute of Building Energetics, Thermal Engineering and Energy Storage (IGTE), Pfaffenwaldring 31, 70569 Stuttgart, Germany 10.3762/bjnano.11.46 Abstract Electrochemical strain microscopy (ESM) is a powerful atomic force microscopy (AFM) mode for the investigation of ion dynamics and activities in energy

• ionic concentration in the material volume under the AFM tip. The ageing of the cathode is found to be governed by a decrease of the electrochemical activity and the loss of available lithium for cycling, which can be stored in the cathode. Keywords: activity; ageing; cathode; electrochemical strain

• the capacity degradation of the samples [23]. Electrochemical strain microscopy (ESM) is a relatively new AFM contact mode, which probes ionic charges accumulated in a small volume under the AFM tip after application of an electric field by measuring the resulting surface strain [24][25][26]. It was

Multilayer capsules made of weak polyelectrolytes: a review on the preparation, functionalization and applications in drug delivery

• Varsha Sharma and
• Anandhakumar Sundaramurthy

Beilstein J. Nanotechnol. 2020, 11, 508–532, doi:10.3762/bjnano.11.41

• stable triazole ring between the successive layers of the LbL assembly. Second, a strain-promoted Cu-free alkyne-azide cycloaddition (SPAAC) uses strained alkynes for reaction with azide, thereby ruling out the issues with toxic copper. A third type of click reaction, the Diels–Alder cycloaddition (DAC

Preparation and in vivo evaluation of glyco-gold nanoparticles carrying synthetic mycobacterial hexaarabinofuranoside

• Gennady L. Burygin,
• Polina I. Abronina,
• Nikita M. Podvalnyy,
• Sergey A. Staroverov,
• Leonid O. Kononov and
• Lev A. Dykman

Beilstein J. Nanotechnol. 2020, 11, 480–493, doi:10.3762/bjnano.11.39

• (Figure 5). Bacterial cultures and growth conditions Bacterial cultures of M. bovis (vaccine strain BCG), M. phlei, and M. smegmatis were obtained from the collection of pathogenic and vaccine microorganisms of animals of Kovalenko Institute of Experimental Veterinary Medicine (Moscow, Russia) [118]. A

• culture of E. coli strain K-12 was obtained from the Collection of the Rhizosphere Microorganisms of the Institute of Biochemistry and Physiology of Plants and Microorganisms RAS (Saratov, Russia) [119]. The cells were grown on a solid nutrient medium for isolation of Mycobacteria (the Löwenstein–Jensen

DFT calculations of the structure and stability of copper clusters on MoS₂

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

• on adsorption structures of Li at Se-doped MoS2, to study the suitability of the system for application in Li-ion batteries. Li adatoms prefer to adsorb above an Mo atom in the monolayer, and cause the system to become metallic once adsorbed. External strain was found to strongly modify the binding

• energy, with binding decreasing as tensile strain increases. While Li can diffuse through the monolayer, the activation energy required is greater than 1 eV and increases with decreasing Se content. Investigation of on-surface diffusion showed that the magnitude of the activation energies is suitable for

Facile biogenic fabrication of hydroxyapatite nanorods using cuttlefish bone and their bactericidal and biocompatibility study

• Satheeshkumar Balu,
• Manisha Vidyavathy Sundaradoss,
• Swetha Andra and
• Jaison Jeevanandam

Beilstein J. Nanotechnol. 2020, 11, 285–295, doi:10.3762/bjnano.11.21

• lattice strain was 0.0055 nm. Evaluation of functional groups The FTIR spectra of CB and CB-Hap (48 h) with high crystallinity are shown in Figure 2, which is essential to analyze their functional groups. The FTIR spectral bands were recorded at 710, 860, 1486, 2522, and 2924 cm−1 for CB which indicates

Nonclassical dynamic modeling of nano/microparticles during nanomanipulation processes

• Moharam Habibnejad Korayem,
• Ali Asghar Farid and
• Rouzbeh Nouhi Hefzabad

Beilstein J. Nanotechnol. 2020, 11, 147–166, doi:10.3762/bjnano.11.13

• based on a 2D model. Governing equations using nonclassical theory The considered models in this study are the Euler–Bernoulli and Timoshenko beam models based on MCST. The Strain energy according to MCST can be expressed as where σij, εij, are classical terms of stress and strain tensors, and mij and

• Timoshenko beam of Figure 3 are described as where u1, u2 and u3 are displacements along the axes x, y and z, respectively, ψ(x,t) is the angular rotation of the beam cross section and w(x,t) is the beam lateral deformation. By replacing the equations of non-zero elements, one can obtain the strain, stress

• , curvature and couple stress matrices along with the non-zero elements of the rotation vector. Additionally, the strain and kinetic energy and the work of external force applied on the beam element are, respectively, defined as [27]. where E is the Young’s modulus, L, A and I are length, cross-sectional area

Fully amino acid-based hydrogel as potential scaffold for cell culturing and drug delivery

• Dávid Juriga,
• Evelin Sipos,
• Orsolya Hegedűs,
• Gábor Varga,
• Miklós Zrínyi,
• Krisztina S. Nagy and
• Angéla Jedlovszky-Hajdú

Beilstein J. Nanotechnol. 2019, 10, 2579–2593, doi:10.3762/bjnano.10.249

• active chains by mechanical measurements To measure the elastic modulus (G), gel cylinders of 1 cm in diameter and height were prepared with the same constitution as described above. G was assessed by vertical stress–strain measurements using an Instron 5942 (Intest kft., Hungary) mechanical tester, and

• its exact value was calculated by determining the stress–strain behavior during unidirectional compression. The temperature and the volume of the gels were constant during deformation, therefore, the Neo–Hooken law could be used to describe the deformation of the gels [21]: where σN is the nominal

• cross-linkers, this method cannot be used to determine the amount of disulfide bonds in these gels. It is a challenging task to determine the cross-linking density in a polymer matrix. Usually, stress–strain measurements are used for this purpose. However, their results are influenced not only by the

Abrupt elastic-to-plastic transition in pentagonal nanowires under bending

• Sergei Vlassov,
• Magnus Mets,
• Boris Polyakov,
• Jianjun Bian,
• Leonid Dorogin and
• Vahur Zadin

Beilstein J. Nanotechnol. 2019, 10, 2468–2476, doi:10.3762/bjnano.10.237

• withstand severe deformation in the elastic regime without fracture. The coating may possibly prevent formation of dislocations. Mechanical durability under high and inhomogeneous strain fields is an important aspect of exploiting Ag and Au NWs in applications like waveguiding or conductive networks in

• the five fcc equilateral triangular segments connected by twin boundaries cannot make 360°, such an exotic structure cannot exist without internal strain with corresponding mechanical stress and stored elastic energy proportional to the volume [6]. Inner stress and peculiar structure of the pentagonal

• electronics [10][11]. In the last case NWs are used as a conductive network in composition with flexible polymer materials such as polydimethylsiloxane (PDMS) [12][13]. The reliability of flexible devices in high-strain conditions will be governed by the mechanical reliability of the individual NWs inside the

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

• Alberto Boretti,
• Lorenzo Rosa,
• Jonathan Blackledge and
• Stefania Castelletto

Beilstein J. Nanotechnol. 2019, 10, 2128–2151, doi:10.3762/bjnano.10.207

The importance of design in nanoarchitectonics: multifractality in MACE silicon nanowires

• Stefania Carapezzi and
• Anna Cavallini

Beilstein J. Nanotechnol. 2019, 10, 2094–2102, doi:10.3762/bjnano.10.204

• two collapsed pillars, such that the length of the non-contact portion is L (Figure 1b), a critical value of L can be estimated from [31] where the term on the left-hand side is the decrease in strain energy if the non-contact region is increased by dL, and the term on the right-hand side is the

Green and scalable synthesis of nanocrystalline kuramite

• Andrea Giaccherini,
• Giuseppe Cucinotta,
• Stefano Martinuzzi,
• Enrico Berretti,
• Werner Oberhauser,
• Alessandro Lavacchi,
• Giovanni Orazio Lepore,
• Giordano Montegrossi,
• Maurizio Romanelli,
• Antonio De Luca,
• Massimo Innocenti,
• Vanni Moggi Cecchi,
• Matteo Mannini,
• Antonella Buccianti and
• Francesco Di Benedetto

Beilstein J. Nanotechnol. 2019, 10, 2073–2083, doi:10.3762/bjnano.10.202

• main phase. A large increase of the crystalline size and defective strain is responsible for the significant line broadening of the diffraction peaks. Still, no prevalent amorphous phase can be observed in the diffractograms. On this basis, the XRD results support the mixed occupancy of the cations in

First principles modeling of pure black phosphorus devices under pressure

• Ximing Rong,
• Zhizhou Yu,
• Zewen Wu,
• Junjun Li,
• Bin Wang and
• Yin Wang

Beilstein J. Nanotechnol. 2019, 10, 1943–1951, doi:10.3762/bjnano.10.190

• by high carrier mobilities can be realized, which are two main focuses of nanoscale electronic devices [1][3][7][13][25][29][30][31]. Previous studies indicated that BP can withstand a tensile stress as high as 10 N/m and a strain up to 30%, and exhibit a direct–indirect–direct bandgap phase

• transition under axial strain [5][32]. The sensitivity to and the resilience against strain make BP an ideal material for strain-sensing electronics and flexible electronic devices. Xiao et al. fabricated few-layer BP nanosheets by chemical vapor transport [25], and observed a phase transition from an

• accumulated isotropically in strain-reduced regions, instead of occurring in the regions with a high tensile strain like in MoS2. Deniz et al. investigated the strain-related optical properties of monolayer BP using first principles calculations [7]. They found that the optical response of BP is sensitive to

High-tolerance crystalline hydrogels formed from self-assembling cyclic dipeptide

• Yongcai You,
• Ruirui Xing,
• Qianli Zou,
• Feng Shi and
• Xuehai Yan

Beilstein J. Nanotechnol. 2019, 10, 1894–1901, doi:10.3762/bjnano.10.184

• hydrogel enhanced along with time. Strain-induced shear-thinning and self-healing abilities of the hydrogel were detected through continuous step changes of oscillatory strain between 500% and 1% (at a constant frequency of 1 rad s−1). Under a high magnitude strain (500%), the modulus of G’’ values

• exceeded G’ values, indicating the breaking of the hydrogel (Figure 3A). By decreasing the strain to 1%, the modulus of G’’ falls below that of G’, indicating the recovery of the hydrogel (Figure 3B). These results illustrated that the recovery of the hydrogel is quick at both 48 h and 240 h, even at the

• fifth test cycle. As compared to that of 48 h, the C-WY hydrogel at 240 h showed a faster recovery speed. The strain-dependent oscillatory rheology results (at 240 h) showed a great anti-shear performance at stains ranging from about 0.1% to about 20%, indicating the shear-thinning behavior of the

Fabrication and characterization of Si_1−xGe_x nanocrystals in as-grown and annealed structures: a comparative study

• Muhammad Taha Sultan,
• Adrian Valentin Maraloiu,
• Ionel Stavarache,
• Jón Tómas Gudmundsson,
• Andrei Manolescu,
• Valentin Serban Teodorescu,
• Magdalena Lidia Ciurea and
• Halldór Gudfinnur Svavarsson

Beilstein J. Nanotechnol. 2019, 10, 1873–1882, doi:10.3762/bjnano.10.182

• annealing results in the periodically arranged columnar self-assembly of SiGe core–shell nanocrystals. An increase in photocurrent intensity by more than an order of magnitude was achieved by annealing. Furthermore, a detailed discussion is provided on strain development within the structures, the

• to surface polarization effects due to local fields, which play a crucial role in systems characterized by strong charge inhomogeneity. Further, the development of strain in the structure influences the size and shape of the NCs, thus resulting in a change of the bandgap energy. A common method to

• incidence X-ray diffraction (GIXRD) and high-resolution transmission electron microscopy (HRTEM). Strain relaxation and its effect on the formation of NCs and the resulting interface integrity was studied and compared with structures having a thicker (ca. 200 nm) SiGe layer [23], deposited by radio

Prestress-loading effect on the current–voltage characteristics of a piezoelectric p–n junction together with the corresponding mechanical tuning laws

• Wanli Yang,
• Shuaiqi Fan,
• Yuxing Liang and
• Yuantai Hu

Beilstein J. Nanotechnol. 2019, 10, 1833–1843, doi:10.3762/bjnano.10.178

• can also be adjusted by applying strain or stress. Up to now, there is only a limited number of studies on tuning and controlling of non-equilibrium minority carriers (NEMC). Zhang et al. [14] studied the I–V characteristics of a p–n junction consisting of a p-type semiconductor without piezo-effect

• = e2/(cε). In the above, strain S and electric field E can be expressed as S = du/dx and E = −dϕ/dx, in which u and ϕ are displacement and electric potential, respectively. c, e and ε are elastic, piezoelectric and dielectric constant, respectively. The one-dimensional Gauss’s law of a piezoelectric p

Novel hollow titanium dioxide nanospheres with antimicrobial activity against resistant bacteria

• Carol López de Dicastillo,
• Cristian Patiño,
• María José Galotto,
• Yesseny Vásquez-Martínez,
• Claudia Torrent,
• Daniela Alburquenque,
• Alejandro Pereira and
• Juan Escrig

Beilstein J. Nanotechnol. 2019, 10, 1716–1725, doi:10.3762/bjnano.10.167

• thickness of these nanostructures was obtained by reducing the cycles of deposition during the ALD process [18][45][46]. The antibacterial activity of CSTiO2 and TiO2 NPs was evaluated by the inhibition of growth of Staphylococcus aureus (control strain ATCC®6538TM and resistant strain MRSA 97-7 and MRSA

• 622-4) and Escherichia coli (control strain ATCC®25922TM and resistant strain E. coli 33.1). When the analysis was done using control strains, the results in Table 1 indicate that CSTiO2 presented an improved antibacterial activity against S. aureus and a similar activity against E. coli in comparison

• to these antimicrobial NPs at this concentration. Thus, a series of TiO2 NPs suspensions at increasing concentrations were examined over 60 min UV-irradiation. Assays revealed that commercial TiO2 NPs presented 28% reduction of S. aureus MRSA 97-7 strain at 300 µg mL−1. Conclusion This is the first