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Based on the review of a wide range of literature, this paper finds that: (1) the average specific surface energy of various single crystals is only 0.8 J/m2. (2) The average specific fracture energy of the rocks with a pre-crack under static cleavage tests is 4.6 J/m2. (3) The average specific fracture energy of the rocks with a pre-cut notch but with no pre-crack under static tensile fracture (mode I) tests is 4.6 J/m2. (4) The average specific fracture energies of regular rock specimens with neither pre-made crack nor pre-cut notch are 26.6, 13.9 and 25.7 J/m2 under uniaxial compression, tension and shear tests, respectively. (5) The average specific fracture energy of irregular single quartz particles under uniaxial compression is 13.8 J/m2. (6) The average specific fracture energy of particle beds under drop weight tests is 74.0 J/m2. (7) The average specific fracture energy of multi-particles in milling tests is 72.5 J/m2. (8) The average specific energy of rocks in percussive drilling is 399 J/m3, that in full-scale cutting is 131 J/m3, and that in rotary drilling is 157 J/m3. (9) The average energy efficiency of milling is only 1.10%. (10) The accurate measurements of specific fracture energy in blasting are too few to draw reliable conclusions. In the last part of the paper, the effects of inter-granular displacement, loading rate, confining pressure, surface area measurement, premade crack, attrition and thermal energy on the specific fracture energy of rock are discussed.

The main purpose of this paper is to compare the chromatographic properties of capillary columns prepared with polymers with different backbone structures and to demonstrate the possibility of polymer differentiation via inverse gas chromatography. With the use of addition and metathesis types of polymerization of tricyclononenes, two new stationary phases were prepared. The metathesis polymer contained double bonds in the polymeric backbone while the backbone of the addition polymer was fully saturated and relatively mobile. A comparison of the separation and adsorption properties of new phases with conventional gas chromatography (GC) stationary phases clearly indicated their non-polar characteristics. However, the difference in the polymer structure appeared to have very little effect on the stationary phase separation properties, so other parameters were used for polymer characterization. The thermodynamic parameters of the sorption of alkanes and aromatic compounds in both polymeric stationary phases were also very similar; however, the entropy of sorption for hydrocarbons with seven or more carbon atoms was different for the two polymers. An evaluation of the specific surface energy of the stationary phases also allowed us to discriminate the two stationary phases.

Inverse gas chromatography (IGC), atomic absorption spectroscopy (AAS), and Fourier-transform infrared spectroscopy (FTIR) were employed to investigate the surface properties of torrefied cardboard samples and their hydrocarbon adsorption. Three torrefied cardboard samples, TC-200, TC-250, and TC-300, were prepared at 200, 250, and 300 °C, respectively. A series of n-alkanes, BTX (benzene, toluene, and p-xylene), and several polar probes (dichloromethane, acetone, ethyl acetate, and tetrahydrofuran) were selected as molecular probes to measure the molar adsorption enthalpies ( $${\Delta H}_{\mathrm{m}}$$ ), dispersive surface energies, and acid–base properties of torrefied cardboard samples. The $${\Delta H}_{\mathrm{m}}$$ values of hydrocarbons measured on TC-300 and TC-250 were more exothermic than those measured for TC-200 by about 19 and 13%, respectively. The $${\Delta H}_{m}$$ values of benzene, toluene, and p-xylene on three torrefied cardboard samples became more negative than those of n-hexane, n-heptane, and n-octane by approximately 17–20%. Surface free energy analysis using molecular probes found that TC-300 exhibited higher dispersive and specific surface energy than TC-250 and TC-200 did. From FTIR spectra and elemental analysis via AAS, C=C moieties in the carbonaceous substances and inorganic mineral compositions are responsible for enhanced dispersive and specific surface energy of TC-300. BTX adsorption isotherms on torrefied cardboard samples were well-fitted using the Freundlich model. Fitted parameters of adsorption isotherms also found that TC-300 had a larger adsorption capacity toward BTX than TC-250, TC-200, and non-torrefied cardboard did.

The thermodynamic properties of bcc and fcc iron phases are calculated at the temperature of the polymorphic bcc–fcc phase transition using the method of calculating properties of a crystal developed before on the base of the Mie–Lenard-Jones pairwise potential. 23 properties of iron and their changes during the bcc–fcc transition have been calculated. The calculations show that the properties, such as: the Gruneisen parameter, the thermal expansion coefficient, and the specific heat are only slightly changed during the bcc–fcc transition. The modulus of elasticity, the specific entropy, the Poisson ratio, and the specific surface energy are changed as well as the molar volume, i.e., within the limit of 1%. The Debye temperature and its pressure derivative decrease during the bcc–fcc transition in the same manner as the distance between the centers of the nearest atoms, i.e., within 2–3%. The analysis of the available experimental data shows that even comparatively correctly measured parameters, such as the thermal expansion coefficient and the modulus of elasticity, are measured with an error higher than the jumps of these parameters during the bcc–fcc transition. It is shown that amorphization or the nanostructurization of a certain iron fraction during the bcc–fcc transition is indicated can contribute to the changes in the iron properties during this phase tr-ansition.

A method for calculating the specific surface energy σ, the isochoric and isobaric derivatives of the function σ with respect to the temperature, and the isothermal derivative of the function σ with respect to the pressure is developed proceeding from the parameters of the Mie–Lennard-Jones pairwise interatomic interaction potential. It is shown that this method is applicable for both macrocrystals and nanocrystals with specified numbers of atoms and with definite surface shapes. To implement this method, the parameters of the pair interatomic potential are determined using a self-consistent method based on the thermoelastic properties of a crystal. This method is tested using Fe, Au, Nb, Ta, Mo, and W macrocrystals at different temperatures and shows good agreement with experimental data. As the nanocrystal size is decreased along the isotherms T = 10, 300, and 2500 K, changes in the surface properties are studied using body-centered cubic (bcc) Ta as an example. It is shown that, at high pressures and low temperatures, the function σ can increase in the case of an isomorphic-isothermal-isobaric decrease in the nanocrystal size.

It has been shown that three singular points related to an amorphous state can be distinguished in the dependence of the first coordination number kn on packing coefficient kp in the structure of a unicomponent material. The equation of state and properties of iron for both these three amorphous structures and the crystal state are calculated on the basis of the Mie–Lennard-Jones pair interatomic potential. It is shown that the chemical potential becomes minimal at kp = 0.45556 and kn = 6.2793; that is, this packing can be assigned to a thermodynamically stable amorphous structure corresponding to a liquid phase. A point that is energetically equivalent to this phase and has the same value of kn but another value of kp (0.6237) is a thermodynamically unstable amorphous structure corresponding to a solid phase. It was shown that the specific surface energy of an amorphous solid metal is higher than that of the amorphous liquid phase but is lower than the specific surface energy of a crystalline metal. This should lead to the fact that the surface of a crystalline metal will tend to amorphization.

The present study considered the problem of halloysite nanoscroll synthesis by energy modeling of the formation of chrysotile and halloysite particles. The main aim of the study was to reveal an energy preference between scrolled and platy morphologies of the particles. Both hydrosilicates possess the ability to scroll spontaneously but relatively facile hydrothermal synthesis of the nanoscrolls is available only to the former, whereas halloysite forms mainly plates under the same conditions. This issue was investigated by a phenomenological energy model, taking into account: (1) strain energy due to the size difference between metal oxide and silica sheets; (2) surface-energy difference on the opposite sides of the layer; and (3) adhesion energy. Calculations showed that the halloysite layer had a significant scrolling potential due to the first energy component, but the surface-energy difference acted in the opposite direction and tried to unbend the layer. In contrast, these two actions were co-directional in chrysotile layers. In both cases, the formation of multi-layered plates became more energy favorable when the specific surface energy of the edges decreased. In the range 0.5–3 J/m2 for the specific surface energy, only halloysite layers showed an energy preference for platy particles over nanoscrolls, especially at small layer sizes. Certain processes, such as hydration, could reduce the corresponding specific surface energy value and, as a result, could stabilize the platy morphology of halloysite at the earliest stages of particle growth under hydrothermal conditions.

A new method for the specific surface energy investigation based on a combination of the force spectroscopy and the method of nanofriction study using atomic force microscopy was proposed. It was shown that air humidity does not affect the results of investigation by the proposed method as opposed to the previously used methods. Therefore, the method has high accuracy and repeatability in air without use of climate chambers and liquid cells. The proposed method has a high local resolution and is suitable for investigation of the specific surface energy of individual nanograins or fixed nanoparticles. The achievements described in the paper demonstrate one of the method capabilities, which is to control the growth mechanism of thin magnetic films. The conditions for the transition of the growth mechanism of thin Ni80Fe20 films from island to layer-by-layer obtained via electrolyte deposition have been determined using the proposed method and the purpose made probes with Ni coating.

The law of specific surface energy variation during the adsorption process is an important basis for studying the mechanisms of coal gas adsorption. Based on the theory of adsorption energy, eight coal samples with different ranks were analyzed using an isothermal adsorption experiment at three different temperatures (30, 40, and 50 °C) and six different pressures (0.1, 0.2, 0.6, 1.0, 1.4, and 1.8 MPa). Then, the single-layer adsorption model and multilayer adsorption model were used to calculate the energy variation during the adsorption process. Just like the adsorption capacity, it is clear that the specific surface energy is inversely proportional to temperature and proportional to gas pressure. The energy difference between the single-layer adsorption and the multilayer adsorption calculation is large. Therefore, the adsorption energy was calculated based on the calorific value, and the comparative analysis shows that the specific surface energy based on the multilayer adsorption model can better reflect the gas adsorption capacity than the single-layer adsorption model. The mechanisms of gas adsorption were explored, such as intermolecular force, energy variation, and specific surface area. The adsorption energy was simulated, which indicated that the energy variation is affected by both coal physical properties and internal chemical structure.

The paper presents results on studying the effect of the stress state on the specific surface energy of the adhesive failure of a Brazil-nut sandwich, made of an aluminum-magnesium alloy, in shear-compression tests.

Nanoalloy shows significant advantages and broad application prospects in chemical catalysis, due to the possessed high specific surface energy and abundant active sites can greatly promote their catalytic performance. In this work, morphology-controlled Cu-Sn alloy nanosheet arrays supported on carbon fiber paper (CP) substrate (Cu-Sn/CP) have been developed by a facile one-step electrodeposition technique at room temperature for the first time. Benefiting from the large active surface area, considerable ion transport channels and strong synergistic catalytic effect between Cu and Sn, the as-prepared Cu-Sn/CP served as a self-supported electrode for efficient nonenzymatic glucose sensing. Under optimized conditions, Cu-Sn/CP electrode offers wide linear ranges of 0.0005–2.0 mM and 2.0–10.0 mM, respectively. The detection limit is as low as 0.061 μM (S/N = 3). Cu-Sn/CP electrode also exhibited excellent selectivity and stability. Additionally, the proposed sensor is proven to be suitable for the detection of glucose in human serum samples.

In recent years, inverse gas chromatography (IGC) and molecular dynamics simulation methods have been used to characterize the solubility parameters and surface parameters of polymers, which can provide quantitative reference for the further study of the surface and interface compatibility of polymer components in the future. In this paper, the solubility parameters and surface parameters of two kinds of common alcoholysis, PVA88 and PVA99, are studied by using the IGC method. The accuracy of the solubility parameters obtained by the IGC experiment is verified by molecular dynamics simulation. On the basis of this, the influence of repeated units of polyvinyl alcohol (PVA) on solubility parameters is studied, so as to determine the appropriate chain length of the PVA for simulation verification calculation. The results show that the solubility parameters are not much different when the PVA chain length is 30 and above, the numerical trends of the solubility parameters of PVA88 and PVA99 at room temperature are the same as the results of molecular dynamics simulation, the dispersive surface energy γsd and the specific surface energy γssp are scattered with the temperature distribution and have a small dependence on temperature. On the whole, the surface energy of PVA99 with a higher alcoholysis degree is higher than that of PVA88 with a lower alcoholysis degree. The surface specific adsorption free energy (ΔGsp) indicates that both PVA88 and PVA99 are amphoteric meta-acid materials, and the acidity of PVA99 is stronger.

The multiple eutectic nitrates with a low melting point are widely used in the field of solar thermal utilization due to their good thermophysical properties. The addition of nanoparticles can improve the heat transfer and heat storage performance of nitrate. This article explored the effect of MgO nanoparticles on the thermal properties of ternary eutectic nitrates. As a result of the decomposition reaction of the Mg(OH)2 precursor at high temperature, MgO nanoparticles were synthesized in situ in the LiNO3–NaNO3–KNO3 ternary eutectic nitrate system. XRD and Raman results showed that MgO nanoparticles were successfully synthesized in situ in the ternary nitrate system. SEM and EDS results showed no obvious agglomeration. The specific heat capacity of the modified salt is significantly increased. When the content of MgO nanoparticles is 2 wt %, the specific heat of the modified salt in the solid phase and the specific heat in the liquid phase increased by 51.54% and 44.50%, respectively. The heat transfer performance of the modified salt is also significantly improved. When the content of MgO nanoparticles is 5 wt %, the thermal diffusion coefficient of the modified salt is increased by 39.3%. This study also discussed the enhancement mechanism of the specific heat capacity of the molten salt by the nanoparticles mainly due to the higher specific surface energy of MgO and the semi-solid layer that formed between the MgO nanoparticles and the molten salt.

To enhance dissolution rate of meloxicam (MX), a poorly soluble model drug, a natural polysaccharide excipient chitosan (CH) is employed in this work as a carrier to prepare binary interactive mixtures by either mixing or co-milling techniques. The MX-CH mixtures of three different drug loads were characterized for morphological, granulometric, and thermal properties as well as drug crystallinity. The relative dissolution rate of MX was determined in phosphate buffer of pH 6.8 using the USP-4 apparatus; a significant increase in MX dissolution rate was observed for both mixed and co-milled mixtures comparing to the raw drug. Higher dissolution rate of MX was evidently connected to surface activation by mixing or milling, which was pronounced by the higher specific surface energy as detected by inverse gas chromatography. In addition to the particle size reduction, the carrier effect of the CH was confirmed for co-milling by linear regression between the MX maximum relative dissolution rate and the total surface area of the mixture (R2 = 0.863). No MX amorphization or crystalline structure change were detected. The work of adhesion/cohesion ratio of 0.9 supports the existence of preferential adherence of MX to the coarse particles of CH to form stable interactive mixtures.

Carbon nanotubes (CNTs) are popular as the chosen reinforcement to achieve excellent mechanical and functional performance in aluminum matrix nanocomposites (AMNCs). However, the key bottleneck problems restrict the strengthening effect using CNTs in AMNCs due to the dispersion homogeneity of CNTs, the distinct differences in physical properties, poor wettability and interface bonding between CNTs and aluminum matrix. This study aims to address these key issues by introducing a continuous SiC nano layer on CNTs surface synthesized from carbon-silicon reaction, acting as a compatibility transition layer prior to mixing with aluminum powders. The results clearly show that the SiC cladding layer provides a good wettability and strong interfacial bonding between CNTs and aluminum matrix, and the interfacial reaction between CNTs and aluminum matrix could be effectively regulated. It is also conducive to reducing the mass density difference and specific surface energy, improving the dispersion of CNTs in matrix. Those factors make a strong contribution to the strengthening effect of CNTs enforcement by achieving high load transfer efficiency. The AMNCs reinforced by this new CNTs/SiC composite powder show clear improvement of mechanical performance without compromising in ductility and electrical conductivity, as compared to AMNCs reinforced by only CNTs or SiC.

The modification of carbon fibres surface has been achieved by high temperature (1000 °C) growth of Fe3O4 magnetic nanoparticles (MNPs) on the surface of carbon fibres using ammonium iron (II) sulphate as a single precursor of the nanoparticles. As a consequence, the formation of MNPs on the surface of unsized carbon fibres increased the interfacial shear strength by 84.3%, as measured by single fibre fragmentation test. Further investigation on interfacial reinforcing mechanism confirmed an increase in average total surface energy of carbon fibres from 58.81 for unmodified carbon fibre to 64.31 mJ/m2 for MNPs decorated fibres. Fundamental analysis revealed a 12.44% increase in average dispersive and no significant reduction in average specific surface energy of carbon fibre after MNPs surface decoration. This led to an increase in interlaminar shear strength from 46.9 to 63.3 MPa due to the strong mechanical interlocking at the MNPs decorated-carbon fibre/epoxy interface which can be described by improve in the dispersive component of the surface energy.

The isothermal dependences of the lattice properties of a nanocrystal on its the size and shape are investigated using the nanocrystal RP model which contains both lattice vacancies and delocalized (diffusing) atoms. A Gibbs surface model is proposed in which a part of the cells is vacant and a part of the atoms are in the delocalized state. The model takes into account that a part of the atoms on the Gibbs surface are delocalized in the bulk manner and the others, on the surface manner. The calculations are performed for argon atoms, which interact by means of the Mie‒Lennard‒Jones pairwise potential. The state equation (P) and the isothermal elastic modulus (B) for argon macro- and nanocrystals along the isotherm T = 10 K are calculated. The calculated data for the macrocrystal are shown to agree well with the experimental data. The isochoric and isobaric dependences of the Debye temperature Θ, the first (γ) and second (q) Gruneisen parameters, the specific surface energy σ, and the functions B and B'(P) = (∂B/∂P)T on the nanocrystal size and shape are studied. It is shown that the Θ, q, σ, B, and B '(P) functions decrease with an isomorphic-isobaric decrease in the nanocrystal size, while the γ value increases. However, in the case of an isomorphic-isochoric decrease in the nanocrystal size, the modulus of elasticity of argon increases. Upon a deviation of the nanocrystal shape from the energy-optimal shape (for the RP(vac) model it is cube), the size dependences of these functions are enhanced.

Surface energy is extensively adopted to predict the surface properties of materials nowadays. Our study was aimed at utilizing the surface free energy measured by inverse gas chromatography to determine inter-particle interactions and to describe the overall behaviour of mixtures. The model drugs of different solubility (tadalafil, levocetirizine dihydrochloride, vardenafil hydrochloride, and amlodipine besylate) and two grades of polyvinylpyrrolidone (Kollidon® 12 PF, Kollidon® VA 64) were mixed in various ratios. Investigated components were characterized using inverse gas chromatography, particle size distribution and specific surface area. We also determined the work of adhesion and cohesion between the components in the binary mixtures. Due to the formation of levocetirizine agglomerates, the effect of mixing time on both components of the surface free energy was also studied for the binary mixture with Kollidon® VA 64. The results based on the energy analysis, especially positive or negative excess surface energies in theoretical and real binary mixtures, indicate that we can predict whether the components can form the desired ordered (interactive) mixture. For this reason, we have proposed, to the best of our knowledge, different approach to predict the interactions between components and their behaviour in the binary mixtures using inverse gas chromatography in terms of the energy balance based only on the surface parameters (surface free energy, dispersive and specific surface energy). Therefore, the approach of energy balance is an innovative and comparatively simple tool for analysis and identification of interactions between components in particulate systems, which can also predict the quality of the mixing.

Within the density functional method, a simple method for determining the dependence of the work function of electrons and specific surface energy of the metal on the relative density of internal vacancies $${{c}_{{v}}}$$ is proposed. Preserving the style of the stabilized jellium model, the preliminarily calculated volume shift of the conductivity zone bottom e(0) ∝ $${{c}_{{v}}}$$ in a specific homogeneous metal is introduced into a one-dimensional functional as the zero-point energy. Using the quantity $${{c}_{{v}}}$$ as a small parameter, linear corrections to the abovementioned quantities are found. The expansion coefficients are expressed in terms of characteristics of a defectless metal. Calculations for Na and Al are carried out by the Kohn–Sham method. Temperature dependences of Al characteristics have been constructed in the thermodynamic limit.

The state equation (P) and isothermal elastic modulus (B) are calculated for argon macro- and nanocrystals at T = 10 K using in the framework the RP(vac)-model of nanocrystal. The isochoric and isobaric (at P = 0) dependences of the Debye temperature (Θ), of the first (γ) and second (q) Gruneisen parameters, as well as the specific surface energy (σ), B and B'(P) = (∂B/∂P)T, are studied as the functions of size and shape of the nanocrystal. As shown, the isothermally isobaric decrease in nanocrystal size is accompanied by a decrease in functions Θ, q, σ, B and B'(P) and by an increase in the γ parameter. However, the elastic modulus rises in the case of the isothermally isochoric decrease in the nanocrystal size. When the nanocrystal deviates from its most energetically optimal shape (a cube for the RP(vac)-model), the size dependences of these functions become more noticeable.

Crushing and grinding, the prerequisite processes in many industries, are employed in areas such as minerals processing and powder technology. During these processes, minerals will cleave or fracture along specific crystal directions, where there are weak inter-planar bonds, generating exposed surfaces. On an exposed mineral surface, different ions can possess different numbers of broken bonds. The total number of broken bonds of all ions on the exposed surface can be considered as the number of broken bonds of the exposed surface. The broken bonds on the exposed surface make the latter more active and determine its reactivity. The broken bond density on the exposed surfaces of fluorite was calculated, enabling the anisotropic surface reactivity of fluorite such as surface energy, surface relaxation, dissolution, wettability, surface charge and adsorbability to be revisited. The results show that the surface broken bond density, which is related to the specific surface energy, could be used to predict the cleavage nature, surface relaxation degree, dissolution rate and surface stability of fluorite crystal. The distribution feature and the number of broken bonds of exposed active ions (such as Ca2+ for fluorite) can be used to predict and explain the anisotropic surface wettability and surface charge, as well as the adsorption mode and strength of organic molecule binding to different exposed surfaces. The calculation of surface broken bonds can serve as useful method to assess mineral surface chemical behavior. This approach is helpful for mineral/material chemistry research in general. Refereed/Peer-reviewed

The changes in the morphology and the electrophysical properties of the Cr/n-Si (111) structure depending on the rapid thermal treatment were considered in this study. The chromium films of about 30 nm thickness were deposited via magnetron sputtering. The rapid thermal treatment was performed by the irradiation of the substrate’s back side with the incoherent light flux of the quartz halogen lamps in nitrogen medium up to 200–550 °C. The surface morphology was investigated, including the grain size, the roughness parameters and the specific surface energy using atomic force microscopy. The resistivity value of the chromium films on silicon was determined by means of the four-probe method. It was established that at the temperatures of the rapid thermal treatment up to 350 °C one can observe re-crystallization of the chromium films with preservation of the fine grain morphology of the surface, accompanied by a reduction in the grain sizes, specific surface energy and the value of specific resistivity. At the temperatures of the rapid thermal treatment from 400 to 550 °C there originates the diffusion synthesis of the chromium disilicide CrSi2 with the wave-like surface morphology, followed by an increase in the grain sizes, roughness parameters, the specific surface energy and the specific resistivity value.

According the JKR theory of adhesivecontact, changes of the contact configuration after formation of the adhesive neck and before detaching are completely reversible. This means, that after formation of the initial contact, the force-distance dependencies should coincide, independently of the direction of the process (indentation or pull-off). In the majority of real systems, this invariance is not observed. The reasons for this may be either plastic deformation in the contacting bodies or surface roughness. One further mechanism of irreversibility (and corresponding energy dissipation) may be chemical heterogeneity of the contact interface leading to the spatial dependence of the specific work of adhesion. In the present paper, this “chemical” mechanism is analyzed on a simple example of an axisymmetric contact (with axisymmetric heterogeneity). It is shown that in the asymptotic case of a “microscopic heterogeneity”, the system follows, during both indentation and pull-off, JKR curves, however, corresponding to different specific surface energies. After the turning point of the movement, the contact area first does not change and the transition from one JKR curve to the other occurs via a linear dependency of the force on indentation depth. The macroscopic behavior is not sensitive to the absolute and relative widths of the regions with different surface energy but depends mainly on the values of the specific surface energy.

Based on small scale laboratory experiments on artificially created discontinuous Pendeli marble specimens, the strength and stability scale effects in uniaxial compression were investigated. Large scale field measurements confirmed the laboratory results. A fractal scaling analysis was further performed on strength, specific surface energy and strain energy release parameters of rock fracture in uniaxial compression. In this experimental and theoretical analysis the effect of : a) the nature of the crack spatial distribution and b) the relative importance of small cracks compared to large cracks, on the scale behaviour of rock-like materials, were established. Several scaling relations were obtained which explain some previous experimental results of various researchers.

One of the challenges when using lithium metal as the anode in rechargeable lithium batteries is the formation and growth of lithium dendrites. The recent observation by He et al. (Nat. Nanotechnol., 2019, 14, 1042-1047) and Zhang et al. (Nat. Nanotechnol., 2020, 15, 94-98) confirm the presence of the root-growth mode for the growth of lithium dendrites (whiskers, spheres and hillocks). In this work, we introduced a non-Newtonian flow model to describe the flow of lithium in lithium metal and incorporate the contributions of viscous dissipation, surface energy, kinetic energy and strain energy in the analysis of the stress relaxation and the growth of a Li-sphere and a Li-whisker. Nonlinear second-order differential equations are derived for the growth of the Li-sphere and the Li-whisker. Closed-form solutions for the temporal evolution of the Li-sphere and the Li-whisker are obtained under the conditions such that the contributions of the surface energy, kinetic energy and strain energy stored in the cantilever beam to the stress relaxation in the lithium metal are negligible. Using the Lippmann relation in specific surface energy, we demonstrated that increasing the electric potential reduces the resistance to the flow of lithium into the Li-sphere and the Li-whisker. The results reveal the need to suppress the cycling-induced strain energy (misfit strain and biaxial modulus) in order to mitigate the growth of Li dendrites (whiskers, spheres and hillocks).

Crystal growth experiments carried out in aqueous solutions, supersaturated with respect to calcite (CaCO3) at room temperature and pressure, show that the lithium ion added to growth solutions not only acts as a habit modifier of calcite, but promotes the nucleation and growth of the two other CaCO3 polymorphs: aragonite and vaterite. This behavior is interpreted on the grounds of foreign adsorption going beyond Langmuir’s isotherm model: two-dimensional (2D)-adsorbed nuclei of Li2CO3 (mineral zabuyelite) can change, under varying Li+ concentrations in solution, the growth habit of calcite, promoting as well both nucleation and growth of aragonite and vaterite, through the mechanism of 2D-epitaxy. Calculation proves how the epitaxy aragonite/2D-zabuyelite reduces the average value of the specific surface energy of aragonite, allowing the nucleation of aragonite and then the coexistence of calcite and aragonite in the same batch. Finally, it is outlined that the 2D lattices fulfilling the epitaxy constraints for the couples calcite/zabuyelite and aragonite/zabuyelite show, as a common feature, a remarkable pseudohexagonality.

Crack resistance of silicon wafers plays a vital role in development of MEMS technologies containing beam elements. In the present research, this characteristic was determined using the Vickers tip indentation method. The critical stress intensity factor KIC and fracture energy GIC of silicon wafers of (100), (110), and (111) crystallographic orientations were evaluated. The measurements were supplemented by imaging of indents using atomic force microscopy (AFM). The correlation of these parameters with the specific surface energy, Young’s modulus E and microhardness H was conducted. The values of E and H were evaluated by nanoindentation. The dependences of KIC and GIC on the load of silicon wafers of (100), (110), and (111) orientations were obtained.

International audience; Surface functionalisation of mesoporous silicas is critical to their application as sorbents and catalyst supports. Here we report the impact of chloride on the physicochemical properties of SBA-15, notably the surface density of reactive hydroxyl groups. Bulk and surface properties were characterised by N2 porosimetry, X-ray diffraction, SEM, TEM, FTIR spectroscopy, and Inverse gas chromatography (IGC). Increasing the HCl concentration from 0.1 → 2.0 M during the sol-gel preparation of SBA-15 increased the surface silanol coverage two-fold, and slightly widened mesopores from 4.2 to 4.9 nm. IGC reveals that the specific surface energy and corresponding surface polarity of SBA-15 correlate with surface silanol properties, and hence tuning the HCl concentration during SBA-15 synthesis offers a facile route to hydrophilic or hydrophobic silicas, and in turn a means to control their functionalisation and sorptive properties.

Huge amount of flue gas desulphurization (FGD) gypsum not only occupies the farmland but also causes severe pollution to the surrounding environment. The most effective way to achieve a high-value utilization of FGD gypsum is to prepare short columnar α-calcium sulfate hemihydrate (α-HH) since short columnar crystals show better mechanical strength than needle-like ones. Here, malic acid, a prolific, inexpensive and environment-friendly modifier was explored for the first time to effectively tune the crystal morphology of α-HH prepared from FGD gypsum in glycerol-water-NaCl solutions. When the concentration of malic acid reached 18.54 × 10−4 mol/kg, α-HH crystals with an average aspect (length-to-diameter) ratio of 1.9 (compared to 29.4 in the absence of malic acid) were prepared. The selective complexation of malic acid with Ca active sites on different α-HH crystal planes played a dominant role in the α-HH crystal morphology transformation, which was then explained by the surface broken bonds theory for the first time. The broken bond number per active Ca atom (Nbper Ca) and broken bond density of Ca atoms (DbCa) on the (2 0 4) end plane were larger than those on the (0 2 0) or (2 0 0) side planes. Therefore, the (2 0 4) end plane was more reactive with organics, resulting in the preferential adsorption of malic acid on the end planes, which reduced the specific surface energy of (2 0 4) and led to an increased exposure of this plane and a decreased exposure of (0 2 0) or (2 0 0) side planes in the final α-HH crystals. Consequently, using malic acid as modifier, the α-HH crystal gradually transformed from a needle-like shape to a short columnar one. This work provided important insights into and perspectives for the selection of crystal modifiers and explanation of the mechanism during the preparation of calcium-containing crystals with controllable morphology.

In this article, the thermodynamic constraints of Brownian coagulation are proposed based on the binary perfectly inelastic collision theory and the principle of maximum entropy. The constraints can be expressed as inequalities with the Taylor series expansion method of moments. The inequalities establish the relationship between the physical parameters (such as temperature and specific surface energy) and the first three integral moments of particles. The inequalities are verified to determine the critical time for Brownian coagulation to reach the thermodynamic equilibrium. The critical time is proportional to the specific surface energy and inversely related to the temperature, which can be used to determine whether the particle size distribution reaches self-preserving form. Moreover, the critical states provide a new approach for detecting the particle specific surface energy with the moment method. The results further explain Brownian coagulation and offer opportunities to improve environmental quality from the viewpoint of thermodynamics.

The unstable cracking behavior in nanoscale single crystal silicon, including initiation, unstable propagation and arrest, is experimentally observed by using a nanoscale trapezoidal-double-cantilever-beam method. A well-controlled multi-step cracking experiment is designed for accurately estimating both the fracture toughness K Ic and the arrest toughness K Ia . The experimental results show that the unstable cracking within a short range of hundreds of nanometers leads to an apparent decrease from K Ic to K Ia , i.e., K Ia K Ic , and produces surprisingly clean crack surfaces with negligible energy dissipation. The specific surface energy of (0 1 1) cleavage plane in nanoscale single crystal silicon is accurately evaluated as γ = 1.83 J / m 2 . These results provide a fundamental understanding of the unstable cracking behavior in a brittle material at the nanoscale.

The effect of air plasma exposure time on the surface energies and acid-base characteristics of polydimethylsiloxane (PDMS) particles was studied. Polymerized PDMS powder was radio frequency induced air plasma irradiated for 2–10 s with the power of 500 W. The efficiency of the plasma treatments was investigated by a new generation inverse gas chromatograph, a surface energy analyzer. The dispersive component of surface energy was determined by the Dorris-Gray method describing the van der Waals interactions, while the specific component of surface energy expressed the surface ability for Lewis acid-base interactions. It was demonstrated that the air plasma treatment did not affect the dispersive and acidic parts of the surface energy and the change of surface hydrophilicity was caused by the raise of the electron-donor ability of the PDMS surface, characterized by van Oss-Good-Chaudhury’s base number. The optimal plasma treatment time was found to be 5 s. Analysis of the specific surface energy and acid-base characteristics with respect to exposure time showed that partial to complete hydrophobic recovery occurred within 38 h.

Based on the evaluation of the properties of crystals, such as surface energy and its anisotropy, the surface melting temperature, the anisotropy of the work function of the electron, and the anisotropy of adsorption, were shown the advantages of the model of coordination melting (MCM) in calculating the surface properties of crystals. The model of coordination melting makes it possible to calculate with an acceptable accuracy the specific surface energy of the crystals, the anisotropy of the surface energy, the habit of the natural crystals, the temperature of surface melting of the crystal, the anisotropy of the electron work function and the anisotropy of the adhesive properties of single-crystal surfaces. The advantage of our model is the simplicity of evaluating the surface properties of the crystal based on the data given in the reference literature. In this case, there is no need for a complex mathematical tool, which is used in calculations using quantum chemistry or modeling by molecular dynamics.

An expression for the Helmholtz free energy is established and the equation of state is derived for a nanocrystal containing vacancies in the lattice and delocalized (diffusing) atoms. The calculations are performed for bcc (body-centered cubic) iron under the isothermal compression of a nanocrystal along the 300-K and 1000-K isotherms. The changes in the specific surface energy (σ), the probability of vacancy formation (ϕ v ) and the probability of atom delocalization (x d ) are studied depending on the size (N) and shape of the nanocrystal at different temperatures (T) and pressures (P). The size dependences are characterized along two isobars: at atmospheric pressure (P = 1 bar) and at P = 100 kbar. As is shown, two P-points arise in the σ(P) isotherms at T ≤ 300 K, where the specific surface energy is independent of the nanocrystal size, which is σ(N) = σ(∞). As the temperature increases, the P points approach each other and at T ≥ 1000 K they vanish in the isotherms. At atmospheric pressure and T = 300 K the amount of vacancies per atom in a nanocrystal is much lower than that in a macrocrystal; however, at T = 1000 K the shredding of the latter leads to an increase in the probability of vacancy formation. Moreover, the smaller the nanocrystal size, the higher the probability of atom delocalization (as well as the self-diffusion coefficient) at any pressure and temperature. The ratio ϕ v /x d decreases with decreasing size of the nanocrystal, and less than a certain size, there is an no-vacansies self-diffusion, at which the number of delocalized atoms is greater than the amount of vacant cells in the nanocrystal lattice, i.e., ϕ v < x d . As the nanocrystal shape becomes different from the energetically optimal, the size dependences of the lattice properties of the nanocrystal are enhanced.

The Griffith theory describes the behavior of brittle materials. For the description of a crack creation, an energy equilibrium is used. At annealed glasses, this equilibrium is reduced to a simple formula containing the mechanical energy in the glass and the surface energy needed for crack creation. The paper deals with the question, whether ball drop test allows the demonstration of the crack creation principles. Furthermore, the specific surface energy is the coefficient that describes the energy needed to create cracks. Therefore it will be discussed here whether ball drop tests produce similar specific surface energy values like static tests, e.g. double cantilever of three-point-bending tests. The testing results show a constant surface energy coefficient at different drop height. Nevertheless, the measured coefficient showed a significant difference to statically determined surface energy coefficients. This was explained by the only partly use of the potential energy of the ball drop for the crack creation. The damping of the glass pane, that is supported in a gasket play a significant role in energy absorption. At a ball drop test the energy amount is defined and the energy input cannot be stopped during the experiment. Despite its easy build-up and conduction, the ball drop test seems not to be an appropriate investigation for the fracture mechanism of brittle glass.

A new interpretation of critical nucleus, which is based on the kinetic analysis of nucleation, is proposed. By critical size of nucleus is meant the size that corresponds to the smallest flux of transition to the next size class. The relationship between the critical size and overpotential and equilibrium surface coverage with adatoms or between the critical size and the specific surface energy and adhesion energy is determined.

It has been well confirmed that metal oxide nanoparticles can simultaneously enhance the flame retardancy and mechanical performance of polymer composites, owning to its catalysis effect and robust characteristic. However, most metal oxide nanoparticles tend to aggregate in polymers due to their high specific surface energy, thus deteriorating their enhancement effect. One simple and effective as well as environmentally friendly functionalization approach is desiderated for the practical application of metal oxide nanoparticles. Tannic acid is a naturally derived polyphenol compound which spontaneously combines with metal ions by coordinate bond. Due to size effect, there are lots of defect situ in the surface of metal oxide nanoparticles which can interact with tannic acid. Therefore, tannic acid was used to modify three kind of representative metal oxide nanoparticles (ZnO, Fe2O3 and Co3O4). The SEM photographs of fracture surface show that the modified metal oxide nanoparticles have a favorite dispersion state in thermoplastic polyurethane (TPU) matrix. As a result, the flame retardancy and mechanical properties of TPU composites have been significantly improved. Specifically, with 4% addition of tannic acid modified metal oxides (MO-TA), the peak HRR value showed a remarkable decrease of 22.7%, 14.1% and 19.3%, compared to pure TPU. Meanwhile, the tensile stress of MO-TA@TPU increased to 39.2, 34.0 and 39.8 MPa from 22.1 MPa of pure TPU, suggesting an effective mechanical performance improvement. The universality of polyphenol compounds to enhance the interfacial interaction between metal oxide nanoparticles and polymer resin opens a novel pathway to prepare high performance polymer composite materials.

Using ethylene glycol (EG) and nano-bubble water (NBW) containing Ar-H2 gas as a mixed solvent, nano-LiFe0.5Mn0.5PO4 is prepared by the solvothermal method. The nanobubbles with sufficient specific surface energy effectively prevent the agglomeration of nanoparticles and homogenize the size of microscopic particles. Meanwhile, the presence of Ar-H2 acts as an antioxidant. XRD, FTIR, and SEM analyses confirm the composition and morphology of the synthesized material. Assembling the prepared material (LFMP@C) into a battery and conduct a charge-discharge test at 1 C, the results show that the specific discharge capacity of LFMP@C is 12.8% higher than that of the control group (LFMP-VC@C) using ascorbic acid as an antioxidant, and 53% higher than that of the control group (LFMP-n@C) without using antioxidant.