Mechanical and thermodynamic properties of Aβ₄₂, Aβ₄₀, and α-synuclein fibrils: a coarse-grained method to complement experimental studies

• Adolfo B. Poma,
• Horacio V. Guzman,
• Mai Suan Li and
• Panagiotis E. Theodorakis

Beilstein J. Nanotechnol. 2019, 10, 500–513, doi:10.3762/bjnano.10.51

• is very close to the minimum free energy state (native). Here, the number of hydrogen bonds that participate in the deformation as a whole is larger as reported by all-atom simulations [4][5]. In contrast, during in vitro self-assembly of neurodegenerative fibrils the fibrilization process is

Polymorphic self-assembly of pyrazine-based tectons at the solution–solid interface

• Achintya Jana,
• Puneet Mishra and
• Neeladri Das

Beilstein J. Nanotechnol. 2019, 10, 494–499, doi:10.3762/bjnano.10.50

• could be their nearly similar stabilization energies. Thermodynamically, a monocomponent system self-assembles into an equilibrium structure that minimizes the Gibbs free energy. The entropic cost associated with adsorption on the substrate, due to the reduced degrees of freedom of molecules, is

Sub-wavelength waveguide properties of 1D and surface-functionalized SnO₂ nanostructures of various morphologies

• Venkataramana Bonu,
• Binaya Kumar Sahu,
• Arindam Das,
• Sankarakumar Amirthapandian,
• Sandip Dhara and
• Harish C. Barshilia

Beilstein J. Nanotechnol. 2019, 10, 379–388, doi:10.3762/bjnano.10.37

• transition between two competing phases at the nucleation stage itself and is found to control square and cylindrical shapes [8]. Considering a rectangular shape nucleus for square-shaped NWs (Figure 5a) and a circular-shaped nucleus for cylindrical NWs (Figure 5b), the difference in Gibbs free energy can be

• expressed as shown in Equation 1 and Equation 2, respectively [8]: Here Δgv is the Gibbs free energy per unit volume and quantified as RT(1,2)/Vm ln(P/Pe), and Δgv is basically a function of growth temperature (T1 = 1223 K, for square-shaped NWs and T2 = 1273 K, for cylindrical-shaped NWs). Again, r1 (r2

A Ni(OH)₂ nanopetals network for high-performance supercapacitors synthesized by immersing Ni nanofoam in water

• Donghui Zheng,
• Man Li,
• Yongyan Li,
• Chunling Qin,
• Yichao Wang and
• Zhifeng Wang

Beilstein J. Nanotechnol. 2019, 10, 281–293, doi:10.3762/bjnano.10.27

• during the dissolution and recrystallization process. The dissolved nickel atoms may continuously attach and bond to the surface of larger nanopetals, and form flower-like structures in order to achieve a minimum total free energy. Chemical characteristics of the composite surface In order to clarify the

Interaction of Te and Se interlayers with Ag or Au nanofilms in sandwich structures

• Arkadiusz Ciesielski,
• Lukasz Skowronski,
• Marek Trzcinski,
• Ewa Górecka,
• Wojciech Pacuski and
• Tomasz Szoplik

Beilstein J. Nanotechnol. 2019, 10, 238–246, doi:10.3762/bjnano.10.22

• interface, accelerate it or inhibit it. This is because of the change in the entropic contribution (ΔS) to the Gibbs free energy (ΔG = ΔH − TΔS, where T stands for temperature) of segregation. Voids at the intersection of multiple grain boundaries have a greater number of both substitutional and

• Gibbs free energy of such migration is limited. That said, diffusive contributions to ΔG (e.g., negative heat of mixing) may induce such migration. Segregation of Te and Se into the metal structure and influence on the permittivity To investigate the semiconductor migration process we have fabricated

Uniform Sb₂S₃ optical coatings by chemical spray method

• Jako S. Eensalu,
• Atanas Katerski,
• Erki Kärber,
• Ilona Oja Acik,
• Arvo Mere and
• Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 198–210, doi:10.3762/bjnano.10.18

• [14][15][38][40]. Growth mechanism of Sb2S3 layers by spray pyrolysis The three most common growth mechanisms of solids can be described by the following equations [41]: Where σSG is the surface free energy of the substrate–gas interface (TiO2–air), σLG is the surface free energy of the layer–gas

• interface (Sb2S3–air) and σSL is the surface free energy of the substrate–layer interface (TiO2–Sb2S3). The surface free energy (σ) is the driving force of fluids and solids to seek a condition of minimum energy by contracting interfacial surface area [41]. Separate 3D islands grow if Equation 1 is valid

Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4–8 nm diameter

• Alexander Rostek,
• Marina Breisch,
• Kevin Pappert,
• Kateryna Loza,
• Marc Heggen,
• Manfred Köller,
• Christina Sengstock and
• Matthias Epple

Beilstein J. Nanotechnol. 2018, 9, 2763–2774, doi:10.3762/bjnano.9.258

• , the equilibrium shape of a nanocrystal can be predicted by minimization of the surface free energy of the crystal for a given enclosed volume. According to the Wulff construction, face-centered cubic (fcc) crystals tend to form truncated octahedral particles with large {111} and small {100} surfaces

Block copolymers for designing nanostructured porous coatings

• Roberto Nisticò

Beilstein J. Nanotechnol. 2018, 9, 2332–2344, doi:10.3762/bjnano.9.218

• –disorder transition at a certain value of χN [43]. In detail, the Flory–Huggins model relies on the thermodynamics of polymer solutions by considering the Gibbs free energy for mixing polymer with solvents. According to the Flory–Huggins theory, to calculate the Flory–Huggins interaction parameter, it must

• be considered that, in a binary system, both polymer and solvent are randomly distributed in the volume, and the heat of mixing is proportional to the volume fraction of polymer segments in the volume. Hence, the free energy minimization during microphase separation favors the formation of various

• minimization of the surface free energy [104]. Analogously as for silica, even titania can be produced with closed spherical pores within the oxidic structures by using high molecular weight PS-b-PEO copolymers (as shown in Figure 6) [105]. Organic–inorganic PS-b-PEO/TiO2 hybrid nanostructured coatings can

Improving the catalytic activity for hydrogen evolution of monolayered SnSe_2(1−x)S_2x by mechanical strain

• Sha Dong and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2018, 9, 1820–1827, doi:10.3762/bjnano.9.173

• opportunity to tune the Gibbs free energy (ΔGH) for hydrogen adsorbed on the monolayer alloys and can be used to enhance HER performance. The HER catalytic properties of the catalyst can also be tuned through strain [42][47][48][49][50][51][52]. Gao et al. [53] demonstrated that a tensile strain is able to

• monolayer was used to avoid the periodic image interactions. The HER can be described by Equation 1 under the conditions pH = 0 and p(H2) = 1bar [64]: The first step of HER is that the H atom is bound to the active site of the catalyst; this step is the rate-determining step [65]. The Gibbs free energy of

• total energy of a molecule of hydrogen, respectively. Using the above values, the Gibbs free energy can be calculated using Equation 4, (a) Top view and (b) side view of monolayer SnSeS. (c) Variation of the lattice constant as a function of Se content in monolayer SnSe2(1−x)S2x. (d) Band gaps as a

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• trace extends only over the Hilbert subspace corresponding to Equation 8. We can equivalently write Equation 13 in the form where F is the free energy. The Josephson current then follows as I =(2e/) ∂F, see Equation 5. Cotunneling regime We now address the CPR in the elastic cotunneling regime, where

• perturbation theory in Hint is justified. We thus wish to compute the free energy F() from Equation 14 to lowest nontrivial order. With W0 = , the standard cumulant expansion gives By virtue of Wick’s theorem, time-ordered correlation functions of the boundary operators (Equation 11) are now expressed in terms

• ABSs for U < Δ while the outer ABSs merge with the continuum for U > Δ [79]. Interestingly, the inner ABS contribution to the free energy for U = 10Δ is minimal for = π, see right panel of Figure 3, and we therefore expect π-junction behavior for By = 0 also in the regime with U Δ and B Δ. We notice

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• (HSE) exchange–correlation functional [15][16] and Wannier90 package [17] implemented in the VASP code. The thermodynamic stability of the material is assessed by the formation energy for the 2D material and is indicated as “the difference in free energy of the 2D material and the lowest value of the

Atomistic modeling of tribological properties of Pd and Al nanoparticles on a graphene surface

• Alexei Khomenko,
• Miroslav Zakharov,
• Denis Boyko and
• Bo N. J. Persson

Beilstein J. Nanotechnol. 2018, 9, 1239–1246, doi:10.3762/bjnano.9.115

• corresponding to a state with lower free energy, but most likely not the free-energy minimum state. This is manifested in Figure 2 in the decrease of Ly with increasing time, and as a strong increase in the temperature T, but the Berendsen thermostat finally results in the imposed temperature. Next, the

Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

• Nor Fazila Khairudin,
• Mohd Farid Fahmi Sukri,
• Mehrnoush Khavarian and
• Abdul Rahman Mohamed

Beilstein J. Nanotechnol. 2018, 9, 1162–1183, doi:10.3762/bjnano.9.108

• ]. Pressure, temperature and the composition of reactants (CH4 and CO2) are emphasized the most in thermodynamic studies using Gibbs free energy minimization technique [13][57][58]. Effect of temperature and pressure in DRM In a DRM reaction, the conversion of CH4 and CO2 increases with an increase in

• al. [56] investigated the effect of temperature on the equilibrium conversion of CH4 and CO2 in a DRM reaction using Gibbs free energy minimization method. They showed that at low temperatures, Trxn < 800 °C (1073 K), the equilibrium conversion of CH4 was different for different ratios of CO2/CH4

A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide

• Shahreen Binti Izwan Anthonysamy,
• Syahidah Binti Afandi,
• Mehrnoush Khavarian and
• Abdul Rahman Bin Mohamed

Beilstein J. Nanotechnol. 2018, 9, 740–761, doi:10.3762/bjnano.9.68

• gasoline engines. In the SCR of NO, a reducing agent must be introduced into the system in order to successfully convert NO into nitrogen (N2), inert gases such as ammonia (NH3), and urea [5]. The reaction system reduces the Gibbs free energy values initiated by the reducing agent; the introduction of

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• , the phase difference becomes: and the intensity of the laser beam crossing through the sample is: The equation of the maximum deviation angle as a function of time is obtained from the total free energy of the system by applying the Euler–Lagrange equation. Elastic continuum theory states that a

• liquid crystal is acting like a continuous fluid and the interaction forces between its molecules are elastic. Taking into account a strong anchoring on the glass support, the free energy density of such a system with added quantum dots is: where fN is the liquid crystal free energy density, fE is a term

• threshold, the deviation angle is very small and the free energy caused by the elastic forces is: where K1 and K3 are the splay and bent elastic constants and θz = ∂θ/∂z. Due to the presence of the QDs, the electric properties of the mixture change. Hence, instead of perpendicular dielectric permittivity

Dynamic behavior of a nematic liquid crystal with added carbon nanotubes in an electric field

• Emil Petrescu and
• Cristina Cirtoaje

Beilstein J. Nanotechnol. 2018, 9, 233–241, doi:10.3762/bjnano.9.25

• the carbon nanotube surfaces, with the glass support and with the applied field. By applying the elastic continuum theory we can write the free energy of a system consisting of a liquid crystal and SWCNTs in electric field as: Here is the elastic free energy of liquid crystal, is the interaction

• free energy of liquid crystals with the applied electric field, is the interaction free energy between LC and SWCNTs and is the interaction free energy of the carbon nanotubes with the applied field. When a planar aligned cell is considered and the electric field is perpendicular to the support (i.e

• ., parallel to the z-axis), the molecular orientation is characterized by the distortion angle θ between the director and the x-axis (Figure 1). Thus, the free energy of the liquid crystal is: where θz = ∂θ/∂z, d is the cell thickness and K1, K3 are elastic constants. The interaction free energy of a liquid

Nematic topological defects positionally controlled by geometry and external fields

• Pavlo Kurioz,
• Marko Kralj,
• Bryce S. Murray,
• Charles Rosenblatt and
• Samo Kralj

Beilstein J. Nanotechnol. 2018, 9, 109–118, doi:10.3762/bjnano.9.13

• parameterize the nematic order parameter as where {q1,q2,q3} are the variational parameters. A convenient metric for the degree of biaxiality is the biaxiality parameter [14][15]: A uniaxial state and configurations with maximum biaxiality are denominated by β2 = 0 and β2 = 1, respectively. Free energy and

• scaling We write the free energy as the sum of volume and surface integrals: The condensation (fc), elastic (fe) and external electric field (ff) free energy densities are expressed as [5][15]: respectively. The quantities A0, B, C are material constants, T* is the supercooling temperature, L is the

• ≈ 0.18. For temperatures close below TIN it follows ξb ≈ 20 nm, ξE(E ≈ 106 V/m) ≈ 1 μm, de(w ≈ 10−4 J/m2) ≈ 1 μm. We obtained nematic structures for the given boundary conditions by minimizing the total free energy of the system. The resulting Euler–Lagrange equilibrium equations for the variational

Growth model and structure evolution of Ag layers deposited on Ge films

• Arkadiusz Ciesielski,
• Lukasz Skowronski,
• Ewa Górecka,
• Jakub Kierdaszuk and
• Tomasz Szoplik

Beilstein J. Nanotechnol. 2018, 9, 66–76, doi:10.3762/bjnano.9.9

• ) and X-ray diffraction (XRD) measurements proved that segregation of germanium into the surface of the silver film is a result of the gradient growth of silver crystals. The free energy of Ge atoms is reduced by their migration from boundaries of larger grains at the Ag/SiO2 interface to boundaries of

Review on optofluidic microreactors for artificial photosynthesis

• Xiaowen Huang,
• Jianchun Wang,
• Tenghao Li,
• Jianmei Wang,
• Min Xu,
• Weixing Yu,
• Abdel El Abed and
• Xuming Zhang

Beilstein J. Nanotechnol. 2018, 9, 30–41, doi:10.3762/bjnano.9.5

• area. Finally, we conclude with a discussion of the technical barriers that hinder their practical application. Basic mechanisms of artificial photosynthesis The APS reaction is not a spontaneous reaction, for example, the Gibbs free energy in water splitting increases by 237 kJ·mol−1, and the required

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes

• Danil A. Petrov,
• Pavel K. Skokov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2807–2817, doi:10.3762/bjnano.8.280

• to the minimum of free energy Here, K11, K22 and K33 are the Frank elastic moduli; χa and are the diamagnetic susceptibility anisotropies of LC and CNTs, respectively; μ0 is the permeability of vacuum; f is the volume fraction of CNTs in the suspension; Wp is the surface density of the coupling

• ). This allows us to neglect the interaction between the CNTs. The term F1 in Equation 1 is the free energy density of elastic deformations of the LC [36]. The contributions F2 and F3 take into account the interaction energies of the LC matrix and CNTs with the magnetic field. The term F4 describes the

• CNTs in LCs [14][18][38]. The last term F5 is the contribution of the entropy of mixing of an ideal solution of CNTs in the LC matrix. As it is known, the state of thermodynamic equilibrium corresponds to the minimum of the free energy (Equation 1), which is a functional of the two vectors n and m, and

The rational design of a Au(I) precursor for focused electron beam induced deposition

• Ali Marashdeh,
• Thiadrik Tiesma,
• Niels J. C. van Velzen,
• Sjoerd Harder,
• Remco W. A. Havenith,
• Jeff T. M. De Hosson and
• Willem F. van Dorp

Beilstein J. Nanotechnol. 2017, 8, 2753–2765, doi:10.3762/bjnano.8.274

• much, we have calculated the changes in Gibbs free energy (ΔG) for particular reactions for isolated molecules at 298 K and a pressure of 1 × 10−4 Pa (1 × 10−6 mbar). Table 2 shows the reaction energies, including those for ClAuPF3 (which is as unstable as ClAuCO [50]) and CF3AuCO. Please note that the

Ferrocholesteric–ferronematic transitions induced by shear flow and magnetic field

• Dmitriy V. Makarov,
• Alexander A. Novikov and
• Alexander N. Zakhlevnykh

Beilstein J. Nanotechnol. 2017, 8, 2552–2561, doi:10.3762/bjnano.8.255

• tensor. The Ericksen stress tensor , included in the stress tensor σki, is determined by the expression where P is the pressure, δki is the Kronecker symbol and FV is the bulk density of free energy of a ferrocholesteric [10][26]: Here K11, K22, K33 are the Frank constants, q0 is the wave number of the

• temperature. The contribution of F1 to the free energy density (Equation 6) determines the energy of orientational elastic deformations of the director field. F2 is the bulk density of the interaction energy of the magnetic field H with an LC matrix (quadrupole mechanism of the magnetic field effect on an FC

• ). F3 is the bulk density of the interaction energy of the magnetic field H with the magnetic moment μ = MSvpn of the particles (the dipole mechanism of the magnetic field effect on an FC). F4 is the contribution of the entropy of mixing of an ideal solution of magnetic particles to the free energy of a

Dynamic behavior of a nematic liquid crystal mixed with CoFe₂O₄ ferromagnetic nanoparticles in a magnetic field

• Emil Petrescu,
• Cristina Cirtoaje and
• Cristina Stan

Beilstein J. Nanotechnol. 2017, 8, 2467–2473, doi:10.3762/bjnano.8.246

• angle approximation and obtain: A theoretical characterization of distortion angle as a function of the time was made considering the model of a ferronematic liquid crystal in a magnetic field similar to the one proposed in [33]. By applying the elastic continuum theory, the free energy density of the

Au nanostructure fabrication by pulsed laser deposition in open air: Influence of the deposition geometry

• Rumen G. Nikov,
• Anna Og. Dikovska,
• Nikolay N. Nedyalkov,
• Georgi V. Avdeev and
• Petar A. Atanasov

Beilstein J. Nanotechnol. 2017, 8, 2438–2445, doi:10.3762/bjnano.8.242

• are arranged along the (111) reflection plane of Au, which possesses the lowest surface-free energy. This crystallite alignment leads to the chain-like nanostructure formation on the substrate, as shown in Figure 1b. The XPS analysis of the as-deposited Au nanostructure is presented in Figure 3. The

Identifying the nature of surface chemical modification for directed self-assembly of block copolymers

• Laura Evangelio,
• Federico Gramazio,
• Matteo Lorenzoni,
• Michaela Gorgoi,
• Francisco Miguel Espinosa,
• Ricardo García,
• Francesc Pérez-Murano and
• Jordi Fraxedas

Beilstein J. Nanotechnol. 2017, 8, 1972–1981, doi:10.3762/bjnano.8.198

• enthalpic interactions [4]. The global parameters that govern the phase behavior of BCPs are given by the χ·N product, where χ stands for the Flory Huggins parameter and N the number of statistical segments in a BCP chain, which is related to the free energy of the system and the composition of the blocks

• becomes evident that when the brush cooling is performed in nitrogen rather than in air, the polymer has the proper surface free energy to induce the alignment of the BCP after the lithography and BCP spin-coating. In order to understand the origin of the influence of the DSA process, we have performed