Antibacterial activity of a berberine nanoformulation

• Hue Thi Nguyen,
• Tuyet Nhung Pham,
• Anh-Tuan Le,
• Nguyen Thanh Thuy,
• Tran Quang Huy and
• Thuy Thi Thu Nguyen

Beilstein J. Nanotechnol. 2022, 13, 641–652, doi:10.3762/bjnano.13.56

• first to report that glycerol can serve as an effective green solvent for BBR NP formation. Being non-toxic, renewable, and biodegradable, and having a suitable dielectric constant to dissolve various compounds such as BBR, glycerol is a promising candidate to replace toxic organic solvents. The effect

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review

• Ioana Marica,
• Fran Nekvapil,
• Maria Ștefan,
• Cosmin Farcău and
• Alexandra Falamaș

Beilstein J. Nanotechnol. 2022, 13, 472–490, doi:10.3762/bjnano.13.40

• polyols, such as high boiling point (up to 320 °C) and dielectric constant, the solubility of simple metal salt precursors, and coordinating properties for surface functionalization preventing agglomeration [27]. The ZnO NPs obtained from polyol synthesis showed excellent crystalline quality and

Systematic studies into uniform synthetic protein nanoparticles

• Nahal Habibi,
• Ava Mauser,
• Jeffery E. Raymond and
• Joerg Lahann

Beilstein J. Nanotechnol. 2022, 13, 274–283, doi:10.3762/bjnano.13.22

• proteins with specific biological functions, such as transferrin, insulin, albumin, mucin, or hemoglobin, may represent powerful candidates as next-generation biologics. The EHD jetting process is influenced by a number of governing principles, such as viscosity and dielectric constant of the premixture

• used for all jetting experiments. This inclusion of ethanol decreased the dielectric constant and surface tension of the solution. The exception was insulin- and mucin-based SPNPs, which were manufactured as described in the Materials section. Furthermore, a homobifunctional amine-reactive macromer

Effects of drug concentration and PLGA addition on the properties of electrospun ampicillin trihydrate-loaded PLA nanofibers

• Tuğba Eren Böncü and
• Nurten Ozdemir

Beilstein J. Nanotechnol. 2022, 13, 245–254, doi:10.3762/bjnano.13.19

• critical component of the bacterial cell walls [9]. 1,1,1,3,3,3-Hexafluoro-2-propanol (HFIP) was used as solvent in the study. It is preferred due to its sufficiently low surface tension, sufficiently high dielectric constant, and volatility [10]. The aim of this study was to produce and characterize

Engineered titania nanomaterials in advanced clinical applications

• Padmavati Sahare,
• Paulina Govea Alvarez,
• Juan Manual Sanchez Yanez,
• Gabriel Luna-Bárcenas,
• Samik Chakraborty,
• Sujay Paul and
• Miriam Estevez

Beilstein J. Nanotechnol. 2022, 13, 201–218, doi:10.3762/bjnano.13.15

• environments, and a high strength-to-weight ratio. Moreover, titanium is somewhat negatively charged at physiological pH values because of the formation of a passive oxide layer, and its dielectric constant is equivalent to that of water [25]. The specific energy structure of TiO2 is responsible for its

Design aspects of Bi₂Sr₂CaCu₂O_8+δ THz sources: optimization of thermal and radiative properties

• Mikhail M. Krasnov,
• Natalia D. Novikova,
• Roger Cattaneo,
• Alexey A. Kalenyuk and
• Vladimir M. Krasnov

Beilstein J. Nanotechnol. 2021, 12, 1392–1403, doi:10.3762/bjnano.12.103

• influence radiative properties. To the contrary, for a whisker-based device a significant fraction of EMW is going into the substrate due to its larger dielectric constant. The difference of dielectric constants of the substrate and vacuum leads to internal reflections and the formation of standing waves in

Enhancement of the piezoelectric coefficient in PVDF-TrFe/CoFe₂O₄ nanocomposites through DC magnetic poling

• Marco Fortunato,
• Alessio Tamburrano,
• Maria Paola Bracciale,
• Maria Laura Santarelli and
• Maria Sabrina Sarto

Beilstein J. Nanotechnol. 2021, 12, 1262–1270, doi:10.3762/bjnano.12.93

• piezoelectric constant and, therefore, a high conversion efficiency. However, these materials are toxic, brittle, and not environmentally friendly. In order to overcome these disadvantages, several studies have investigated polymeric piezoelectric materials and nanostructured materials with high dielectric

• constant and good piezoelectric properties suitable for the fabrication of flexible piezoelectric nanogenerators [1][2][3][4][5][6][7]. One of the most extensively investigated piezoelectric polymers is poly(vinylidene fluoride) (PVDF). This polymer has attracted a lot of interest due to its excellent

Electrical, electrochemical and structural studies of a chlorine-derived ionic liquid-based polymer gel electrolyte

• Ashish Gupta,
• Amrita Jain,
• Manju Kumari and
• Santosh K. Tripathi

Beilstein J. Nanotechnol. 2021, 12, 1252–1261, doi:10.3762/bjnano.12.92

• techniques, such as the addition of ionic liquids (ILs) with low viscosity and high dielectric constant values or some suitable fillers have been used by the research community to increase the ionic conductivity of polymer electrolytes [6][7]. As mentioned above, one way to increase the ionic conductivity is

• ][23], fluoropolymers such as poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) have received much attention from the research community as potential polymer hosts for the synthesis of polymer electrolytes [10][11][24][25]. The dielectric constant value of PVdF-HFP is ≈8.4 and it comprises a

• tabulated in Table 2. Dielectric studies are some of the most important techniques to understand the effect of plasticizers, blending of polymers, inter-/intramolecular interactions, their transport mechanism, and relaxation behavior at a molecular level. Figure 6a and Figure 6b show the dielectric constant

First-principles study of the structural, optoelectronic and thermophysical properties of the π-SnSe for thermoelectric applications

• Muhammad Atif Sattar,
• Najwa Al Bouzieh,
• Maamar Benkraouda and
• Noureddine Amrane

Beilstein J. Nanotechnol. 2021, 12, 1101–1114, doi:10.3762/bjnano.12.82

• the cubic π-SnSe alloy is presented in Figure 11a as a function of the photon energy. It can be observed that for the π-SnSe system, the static dielectric constant ε1(0) is 12.82, which is positive. The positive value of the real dielectric tensor ε1(ω) suggests that the studied material is a

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

Colloidal particle aggregation: mechanism of assembly studied via constructal theory modeling

• Scott C. Bukosky,
• Sukrith Dev,
• Monica S. Allen and
• Jeffery W. Allen

Beilstein J. Nanotechnol. 2021, 12, 413–423, doi:10.3762/bjnano.12.33

• layers result in repulsion between two particles, this force is constantly opposed by the attractive van der Waals force. The balance between these interparticle forces gives the total DLVO force and highly depends on system parameters, such as the electrolyte concentration and fluid dielectric constant

• dielectric constant, respectively. Conversely, the attractive van der Waals force is given by [14]: where the characteristic energy scale is set by the Hamaker constant, A. It is noted that Equation 1 and Equation 2 assume spherical particles of equal radius and a sufficiently small separation distance (a

• lattice arrangements are shown in Figure 5 and Figure 6, respectively. The total DLVO forces from both uniform (left) and non-uniform (right) aggregation are plotted as functions of particle spacing or particle radius and electrolyte concentration or fluid dielectric constant. The same general trends were

Structural and optical characteristics determined by the sputtering deposition conditions of oxide thin films

• Petronela Prepelita,
• Florin Garoi and
• Valentin Craciun

Beilstein J. Nanotechnol. 2021, 12, 354–365, doi:10.3762/bjnano.12.29

• that at a wavelength of 430 nm the refractive index of the films approaches a minimum value. The quality of the dielectric materials is also determined by the dielectric constant values. The values of the dielectric constant were obtained by using the Drude method [58][59] and the spectral absorption

• of the oxide films. This allowed for the assessment of the permittivity and polarizability of the material, as well as the density of states in the band interval. Based on calculus, the value of the real dielectric constant (εr) can be obtained by: and the relationship to compute the imaginary

• dielectric constant is: where n is the refractive index and k is the extinction coefficient. Figure 12 shows the variations of real and imaginary parts of the dielectric constants of ZnO and SiO2 films with photon energy. It can be seen that the value of the real part is higher than that of the imaginary

Mapping the local dielectric constant of a biological nanostructured system

• Wescley Walison Valeriano,
• Rodrigo Ribeiro Andrade,
• Juan Pablo Vasco,
• Angelo Malachias,
• Bernardo Ruegger Almeida Neves,
• Paulo Sergio Soares Guimarães and
• Wagner Nunes Rodrigues

Beilstein J. Nanotechnol. 2021, 12, 139–150, doi:10.3762/bjnano.12.11

• work is to determine the varying dielectric constant of a biological nanostructured system via electrostatic force microscopy (EFM) and to show how this method is useful to study natural photonic crystals. We mapped the dielectric constant of the cross section of the posterior wing of the damselfly

• Chalcopteryx rutilans with nanometric resolution. We obtained structural information on its constitutive nanolayers and the absolute values of their dielectric constant. By relating the measured profile of the static dielectric constant to the profile of the refractive index in the visible range, combined with

• optical reflectance measurements and simulation, we were able to describe the origin of the strongly iridescent wing colors of this Amazonian rainforest damselfly. The method we demonstrate here should be useful for the study of other biological nanostructured systems. Keywords: dielectric constant

Bulk chemical composition contrast from attractive forces in AFM force spectroscopy

• Dorothee Silbernagl,
• Media Ghasem Zadeh Khorasani,
• Natalia Cano Murillo,
• Anna Maria Elert and
• Heinz Sturm

Beilstein J. Nanotechnol. 2021, 12, 58–71, doi:10.3762/bjnano.12.5

• turn generate oscillating dipoles in an adjacent body. The response of a specific material in an oscillating electromagnetic field E(f) is described by the dielectric constant εr(f) which can be extracted from the absorption spectrum of the material. Hence, how materials (e.g., the sample (S) and the

• tip (T)) interact in a medium (m) is defined by the difference in the dielectric responses. The Hamaker coefficient AHam can be derived from the relative differences of the dielectric constant εS(f), εT(f), and εm(f), summed up over all the frequencies at which the fluctuations can occur (UV–vis–IR

Kondo effects in small-bandgap carbon nanotube quantum dots

• Patryk Florków,
• Damian Krychowski and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

• effects of interaction play a more fundamental role. Carbon nanotubes are quasi one-dimensional systems, and the role of correlations further increases in quantum dots due to additional confinement. Of importance is also the low dielectric constant, which is especially low in suspended nanotubes [36]. A

Absorption and photoconductivity spectra of amorphous multilayer structures

• Oxana Iaseniuc and
• Mihail Iovu

Beilstein J. Nanotechnol. 2020, 11, 1757–1763, doi:10.3762/bjnano.11.158

• , Nt is the concentration of traps, e is the electron charge, µ is the drift mobility, ε is the dielectric constant, t = Δ/(kBT) (Δ is the parameter of the trap distribution, kB is the Boltzmann constant, T is the absolute temperature), V is the applied voltage, and d is the sample thickness. The

Controlling the electronic and physical coupling on dielectric thin films

• Philipp Hurdax,
• Michael Hollerer,
• Larissa Egger,
• Georg Koller,
• Xiaosheng Yang,
• Anja Haags,
• Serguei Soubatch,
• Frank Stefan Tautz,
• Mathias Richter,
• Alexander Gottwald,
• Peter Puschnig,
• Martin Sterrer and
• Michael G. Ramsey

Beilstein J. Nanotechnol. 2020, 11, 1492–1503, doi:10.3762/bjnano.11.132

• considered. The capacitor model and the interlayer dielectric constant The behavior observed in the ARUPS series of Figure 4 and Figure 5 is consistent with the predictions from the capacitor model expressed in Equation 1. Figure 6a depicts the relationship between the SOMO intensity (ISOMO) and the work

• monolayer and thus the charge density (σ) on the surface. For the capacitor model to be predictive and quantitative for ultrathin decoupling layers, a realistic value for their dielectric constant (εr) is required. This can be estimated from a molecular dosing series, such as in Figure 5. Figure 6b shows

• work function upon adsorption of the molecules (ΔΦ = Φmol − ΦMgO, where Φmol is the final work function after adsorption of the molecules) is very well described by electrostatics with a simple capacitor model given by where σ is the average charge density in the molecular film, εr is the dielectric

Structural and electronic properties of SnO₂ doped with non-metal elements

• Jianyuan Yu,
• Yingeng Wang,
• Yan Huang,
• Xiuwen Wang,
• Jing Guo,
• Jingkai Yang and
• Hongli Zhao

Beilstein J. Nanotechnol. 2020, 11, 1321–1328, doi:10.3762/bjnano.11.116

• dielectric constant is εr = 0, the concentration of positive and negative charges is the same, and positive and negative charges are free to move. When the probability of collision of free electrons in a solid is 0, the dielectric function is where ωp is the plasma frequency. ωp is the intrinsic

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• and 2.03, respectively. A different dielectric constant may lead to a different potential decay at the interfaces, which in turn may influence the reaction rates. However, since the difference in dielectric constant between the two solvents is small, we propose the first explanation as being more

High permittivity, breakdown strength, and energy storage density of polythiophene-encapsulated BaTiO₃ nanoparticles

• Adnanullah Khan,
• Amir Habib and
• Adeel Afzal

Beilstein J. Nanotechnol. 2020, 11, 1190–1197, doi:10.3762/bjnano.11.103

• exhibit irregular surface profile, which confirms the occurrence of sub-micrometer clusters and nanoscale particles on the surface. The permittivity or dielectric constant (ε′), loss tangent (tan δ), dielectric loss (ε″), and ac conductivity (σac) of the synthesized materials are measured as a function of

• two phases prevent the free-charge accumulation at the interface and, therefore, improve the breakdown strength. Furthermore, in situ oxidative polymerization of PTh on BTO surfaces allows for the inclusion of 90 wt % BTO, which results in a high dielectric constant. This means that the tremendous

• increase in the energy storage density of core–shell BTO-PTh nanoparticles is due to the combined effect of high dielectric constant (ε′) and improved breakdown strength (Eb). These results are noteworthy considering the previous examples of BTO-polymer composite dielectric materials. Table 1 offers a

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

• Kamila A. Szewczyk,
• Izabela A. Domagalska,
• Artur P. Durajski and
• Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

• result is radically different from the data obtained for graphene/SiO2 [33]. In addition, hBN monolayers exhibit a high temperature stability, a low dielectric constant (ε = 3–4), and a high thermal conductivity [34]. The band gap of hBN is about 5.9 eV [35]. Furthermore, which is also important, hBN is

Excitonic and electronic transitions in Me–Sb₂Se₃ structures

• Nicolae N. Syrbu,
• Victor V. Zalamai,
• Ivan G. Stamov and
• Stepan I. Beril

Beilstein J. Nanotechnol. 2020, 11, 1045–1053, doi:10.3762/bjnano.11.89

• the reflection spectra for both Е||с and Е⟂с polarization cases at 300 K. The calculations showed that for the polarization Е||с the background dielectric constant (εb) is equal to 7.5, the energy of the transversal exciton (ωТ) is 1.192 eV, the longitudinal-transversal splitting (ωLT) is 15 meV, the

• effective mass (μ*) is calculated for the excitons A, B, C and D. For excitons A and B when the background dielectric constant is εb = 7.5 and the binding energy is Ry = 130–136 meV the reduced exciton mass is μ* = 0.56m0. For the exciton series C at εb = 7.5 and at the binding energy Ry = 82 meV, the

A new photodetector structure based on graphene nanomeshes: an ab initio study

• Babak Sakkaki,
• Hassan Rasooli Saghai,
• Ghafar Darvish and
• Mehdi Khatir

Beilstein J. Nanotechnol. 2020, 11, 1036–1044, doi:10.3762/bjnano.11.88

• permittivity and system volume, respectively. The relative dielectric constant, εr, is related to the susceptibility, χ, as [26][27]: The photocurrent is calculated by first-order perturbation theory in the framework of the Born approximation. In short, light–electron interaction is added to the Hamiltonian as

High dynamic resistance elements based on a Josephson junction array

• Konstantin Yu. Arutyunov and
• Janne S. Lehtinen

Beilstein J. Nanotechnol. 2020, 11, 417–420, doi:10.3762/bjnano.11.32

• connected in series, each being a Al–AlOx–Al junction with a gap of about 400 µV. The charging energy, Ec = e2/2C, of each SIS contact (considering it to be a plate capacitor with dielectric constant ε ≈ 10, area 100 × 100 nm and distance between plates ≈2 nm) is about two orders of magnitude higher than

Advanced hybrid nanomaterials

• Andreas Taubert,
• Fabrice Leroux,
• Pierre Rabu and
• Verónica de Zea Bermudez

Beilstein J. Nanotechnol. 2019, 10, 2563–2567, doi:10.3762/bjnano.10.247

• as functionalized films with high dielectric constant, or, in the case of optical applications, this consists also in embedding different types of nanoparticles. In the first example, “Co-intercalated layered double hydroxides as thermal and photo-oxidation stabilizers for polypropylene”, the

• fire retardancy and gas permeation in a low molecular weight epoxy resin [28]. Regarding specific applications, the dielectric properties were investigated by broadband dielectric spectroscopy (BDS) in “Nanocomposite–parylene C thin films with high dielectric constant and low losses for future organic