Differential Scanning Calorimetric Measurements Research Articles

Unraveling the effect of short-term high-temperature storage on the performance and thermal stability of LiNi0.5Co0.2Mn0.3O2/graphite battery

In practical applications, the batteries are usually subjecting to short-term high-temperature storage (e.g., 80 °C for several days), which is quite different from long-term storage with temperature lower than 60 °C. Herein, the effect of such a short-term high-temperature storage on the performance of LiNi0.5Co0.2Mn0.3O2/graphite battery under normal cycling (under 1C at 25 °C) is studied by electrochemical characterizations and post-mortem analysis. Due to the thickened Solid-Electrolyte-Interface (SEI) film on the stored anode, the loss of active lithium significantly increases after cycling and leads to increased cathode state of charge (SOC) offset. On the other hand, the thickened Cathode-Electrolyte-Interface (CEI) layer on stored cathode consists of more organic contents due to particle cracking. Such interface degradations hinder lithium ion diffusion, causing increased polarization, SOC offset, and reduced inherent performance of the electrodes. By quantificationally analyzing the degradation factors, it is revealed that the polarization related to interfaces is the dominating factors for battery degradation, and the cathode decay rate is distinctly expedited after short-term high-temperature storage. Additionally, the decreased thermal stability of electrode materials is observed by differential scanning calorimeter (DSC) measurements. In all, the short-term high-temperature storage accelerates the battery aging during normal cycling and reduces the battery safety.

Investigation of Mechanical and Hygroscopic Properties for the Semi-crystalline Polypropylene Polymer Via Experiments and Molecular Dynamics

In this study, mechanical properties and moisture related hygroscopic characteristics of semi-crystalline polypropylene (PP) were investigated via molecular dynamics (MD) simulations and experiments with respect to degree of crystallinity. To control the degree of crystallinity, experimental samples were treated by an annealing process while MD models were constructed through combination of crystalline and amorphous layers. In order to evaluate crystal structure and calculate degree of crystallinity for the experimental samples, X-ray diffraction (XRD) and differential scanning calorimeter (DSC) measurements were conducted. For comparison with the experimental samples, an XRD simulation was performed for the MD models. Then, the mechanical and hygroscopic properties such as elastic modulus and moisture saturation amount were studied with respect to the degree of crystallinity through experiment and MD simulation. It was found that the effects of the degree of crystallinity on the hygro-mechanical properties of the semi-crystalline PP can be predicted from the developed MD simulation. It is expected that the simulation approach developed in our study can be widely used to predict the characteristics of the semi-crystalline PP with varying degree of crystallinity.

Re-assessment of the Mg–Zn–Ce system focusing on the phase equilibria in Mg-rich corner

The Mg–Zn–Ce alloys exhibit good creep resistance and strength at elevated temperature due to the formation of intermetallic compounds. However, the ternary compounds and phase equilibria in the Mg-rich corner are still controversial which restrains the development of Mg–Zn–Ce alloys. The present work experimentally investigated the phase equilibria in Mg-rich corner of the Mg–Zn–Ce system at 350 and 465 °C and thermodynamically assessed the Mg–Zn–Ce system. The existence of ternary compounds τ1 and τ3 were confirmed by a combination of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystal structure of τ1 was resolved as space group of Cmc21 with a = 0.9852(2)–1.0137(2) nm, b = 1.1361(3)–1.1635(3) nm and c = 0.9651(2)–0.9989(2) nm by Rietveld refinement of the XRD pattern. Three invariant reactions, L→τ3+CeMg3+CeMg12, L+CeMg12→α-Mg+τ1 and L+τ1→τ2+α-Mg, were revealed by differential scanning calorimeter (DSC) measurement and microstructure characterization. Then, a set of self-consistent thermodynamic parameters was thereafter constructed by assessing the phase equilibria, solid solubilities of CeMg12, τ1, CeMg3 and τ3, as well as the formation enthalpies of binary and ternary compounds calculated by density functional theory. The comparison of calculated phase diagram with experimental results and the literature were discussed. The calculated isothermal section of Mg–Zn–Ce system at 465 °C agreed with our experimental data. The two three-phase equilibria, τ1+α-Mg+CeMg12 and CeMg3+τ3+CeMg12, were confirmed in the Mg-rich corner. This thermodynamic database can be used for the further alloys design of Mg–Zn–Ce system.

Shuffle-nanodomain regulated strain glass transition in Ti-24Nb-4Zr-8Sn alloy

The unprecedented properties of multi-functional metastable β-Ti alloys, including superelasticity over a wide temperature range, ultra-low modulus, and Invar and Elinvar anomalies, have attracted a great deal of attention. Persistent research efforts have been made towards the understanding of the origins of these unique properties. In this article we report a novel shuffle-nanodomain regulated strain glass transition in a metastable β-Ti alloy, Ti-24Nb-4Zr-8Sn (wt.%, Ti2448), which could be the dominant transformation pathway that offers these unique properties. Using the ex-situ aberration-corrected scanning transmission electron microscopy and in-situ cooling transmission electron microscopy, we find that randomly distributed {011}〈01¯1〉β O′ phase (orthorhombic, shuffle only) nanodomains embedded in the β phase (BCC) matrix at room temperature transform to α″ phase (orthorhombic) with a continuous increase in the amount of {21¯1}〈1¯1¯1〉β shear upon cooling or loading. Crystallographic analysis shows that the shuffle of the O′ phase will restrain the twelve possible shears that transform a BCC lattice to α″ martensite to only two. Thus, the randomly distributed O′ nanodomains prevent the formation of long-range-ordered, self-accommodating transformation-strain domain patterns seen in normal martensitic transformations and suppress completely the sharp first-order, auto-catalytic and avalanche-like martensitic transformation into a high-order-like (continuous) strain glass transition. Such a continuous β → O′ → α″ strain glass transition has been confirmed by dynamic mechanical analysis, resistivity and differential scanning calorimetric measurement. This unique transition pathway allows us to offer new insights into the unique properties found in this alloy.

Enhanced magnetoelectric coupling and dielectric constant in flexible ternary composite electrospun fibers of PVDF-HFP loaded with nanoclay and NiFe2O4 nanoparticles

Magnetoelectric flexible composite fiber mats with superior room temperature magnetoelectric properties.

High cyclic stability of electrocaloric effect in relaxor poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) terpolymers in the absence of ferroelectric phase transition

The incorporation of bulky defects into ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymers can result in a relaxor behavior, accompanied by outstanding electrocaloric properties near room temperature. However, it remains elusive whether ferroelectric transition occurs in relaxor terpolymers, which is critical for the design of electrocaloric cooling devices. In this work, we study the electrocaloric fatigue in poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (61.8/30.4/7.8 mol. %) terpolymer, in which we revisit its controversial issue of the phase transition. We observe that the electrocaloric response of the terpolymers remains nearly constant (ΔS = 25.5 J K−1 kg−1, ΔT = 5.1 K at 100 MV m−1) within 50 cycles at different temperatures around room temperature. Moreover, we conduct temperature-dependent X-ray diffraction and Fourier-transform infrared spectroscopy measurements on the terpolymer to provide insights into the evolution in intermolecular lattice spacing and intramolecular conformation. We find no clear evidence of the ferroelectric-to-paraelectric phase transition near the temperature range, where differential scanning calorimeter measurement displays an endothermic peak.

Controlled Phase Behavior of Thermally Sensitive Poly(N-isopropylacrylamide/ionic liquid) with Embedded Au Nanoparticles.

We have synthesized a series of poly(N-isopropylacrylamide/ionic liquid) with deposited Au nanoparticles. The size of the nanoparticle range was varied from 10 to 35 nm, and these were characterized by transmission electron microscopy analysis. Ionic liquids (IL) were chosen by varying the polymerizable unit to be both in cationic (allyl) and anionic (acrylate) moiety. One-pot polymerization was done with N-isopropylacrylamide and IL using ammonium persulphate as the initiator, to which were added already prepared Au NPs. These thermally sensitive composites formed, possessed reversible swelling/deswelling abilities in water, and demonstrated a reversible visible phase transition, which was detected by differential scanning calorimetric measurements. The lower critical solution temperature (LCST) showed dependency on the size of nanoparticles and the IL independently. It was seen that the LCST of PNIPAM-based composite films can be tuned from 32 °C to a range of 23–67 °C by choosing the desired Au NP size, its concentration and kind of IL.

Hydration dynamics in aqueous Pluronic P123 solution: Concentration and temperature dependence.

Here, we report the concentration (0 ≤ wt. % ≤ 30) and temperature (293 ≤ T/K ≤ 318) dependent structural and dynamical changes in an aqueous solution of a triblock copolymer (Pluronic P123) using dielectric relaxation spectroscopy (DRS), covering a frequency regime, 0.2 ≤ ν/GHz ≤ 50. Remarkable existence of slow water molecules, ∼2 times slower than bulk type water, along with bulk-like water molecules has been detected in the present DR measurements. Differential scanning calorimetric measurements support this DR observation. The signature of the sol-gel phase transition (∼15.0 wt. %, 293 K) and temperature induced extensive dehydration (>60%) for P123 molecules, which are the other notable findings of the present work. Moreover, the rate of dehydration with temperature has been found to depend on the phase of the medium. However, dehydration follows a nonlinear pattern in both sol and gel phases. A subnanosecond (∼90 ps) component, possibly originating from the hydrogen bond relaxation dynamics of the terminal C-O-H of polymer chains, has also been observed.

RDX solubility in TNT at high temperatures

The solubility of RDX (hexahydro-1,3,5-tri-nitro-1,3,5-triazine) in TNT (2,4,6-trinitrotoluene) at elevated temperatures is required to accurately predict the response of Comp-B3 (60:40 RDX:TNT) during accidents involving fire. As the temperature increases, the TNT component melts, the RDX partially dissolves in the liquid TNT, and the remaining RDX melts (203 $$^\circ$$ C) as the Comp-B thermally ignites. In the current work, we used a differential scanning calorimeter (DSC) to estimate the solubility of RDX in TNT at the melting point of RDX. Most DSC measurements of Comp-B3 do not show an RDX melt endotherm. The absence of an endotherm associated with the RDX melt has been interpreted as RDX being completely dissolved in TNT before reaching the melting point. We have observed that the endotherm is not absent, but is masked by exothermic reactions occurring at these elevated temperatures. We have inhibited the exothermic reactions by venting our DSC samples and measuring the RDX melt endotherm in our Comp-B3 samples at about 203 $$^\circ$$ C. Using the measured heat flow associated with the RDX melt and the latent melting enthalpy of RDX, we have approximated the solubility of RDX in TNT to be roughly 50–100 $$\hbox {g}_{\mathrm{RDX}}$$ per 100 $$\hbox {g}_{\mathrm{TNT}}$$ . The broad range is based on corrections for exothermic reactions occurring as the RDX melts.

The experimental study of silica nanoparticles strengthened polymer gel system

To research the action mechanism of silica nanoparticles in polymer gel, a novel silica nanoparticle strengthened polymer gel (SNSPG) with partially hydrolyzed polyacrylamide (HPAM) and organic zirconium is studied. After adding nanoparticles, when the concentration of HPAM is low (˂0.8 wt%), viscoelasticity of this system has few increases compared with before. The nanoparticles are not strong to bridge the loose three-dimensional network structure. Furthermore, Dynamic Light Scattering (DLS) and zeta potential measurements were tested to explain enhancement of high concentration system (0.8 wt%) by nanoparticles. Differential Scanning Calorimeter (DSC) and Environmental Scanning Electron Microscope (ESEM) measurements results together support the action mechanism of this research. In high polymer concentration, proper amounts of nanoparticles participated in the gelation process to make polymer gel tighter, while too many nanoparticles blocked cross-linking of polymer and cross linker to weaken the system enhancement. This research develops a strengthened polymer gel system which has broad application prospects, and the action mechanism this research proposed provides theoretical support for industrial production.

Crystallization behavior of Li1+xAlxGe2-x(PO4)3 glass-ceramics: Effect of composition and thermal treatment

Lithium aluminum germanium phosphate (LAGP) glass-ceramics are promising solid electrolytes for all solid-state lithium ion batteries and other electrochemical applications. LAGP glass-ceramics (Li1+xAlxGe2-x(PO4)3, x = 0.5–0.8) were synthesized using a two-step heat treatment based on characteristic temperatures from Differential scanning calorimeter (DSC) analysis. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the crystal phases and their morphologies. Our results show that high purity ion conductive phase can be obtained for the compositions with P/Ge = 2.3 and 2.4 by a two-step heat treatment, instead of the commonly adopted single step heat treatment for composition with P/Ge = 2.0. Electrochemical impedance spectroscopy (EIS) measurements show that Tg + 60%∆T (∆T = Tc-Tg) is the optimal nucleation temperature to obtain high ionic conductivity. Crystallization energies were calculated from the modified Kissinger equation based on DSC measurements and it was concluded that the crystal phase form mainly through internal nucleation. We have found in this paper that, by using a two-step heat treatment, high phase purity LAGP glass-ceramics with lower GeO2 concentration can be obtained to achieve high ionic conductivity.

Dynamics at the non-ionic micelle/water interface: Impact of linkage substitution.

The impact of atom substitution on the glycoside linkage bridging the head and the tail parts in a nonionic surfactant molecule on aqueous dynamics of the resultant micellar solutions has been explored, employing time-resolved fluorescence and dielectric relaxation (DR) measurements. We have utilized n-octyl-β-D-glucopyranoside (OG) and n-octyl-β-D-thioglucopyranoside (OTG) as nonionic surfactants where the oxygen atom in the glucopyranoside unit is substituted by a sulfur atom. The substitution impact is immediately reflected in the dynamic light scattering measurements of aqueous solutions where the estimated size of the OTG micelles is found to be approximately four times larger than the OG micelles. Steady state spectral features obtained by using a fluorescent probe solute, coumarin 153 (C153), in these micellar solutions are quite similar and indicate locations of the solute at the micelle/water interface for both the surfactants. Interestingly, significant differences in the rotational and solvation dynamics of C153 in these two micellar solutions have been registered. The corresponding DR measurements do not indicate any signature of relaxation typical of bound water. The absence of bound water is further supported by the differential scanning calorimetric measurements. However, the typical slow solvation time scale for aqueous micellar solutions has been observed for these surfactants. Fluctuations in the solute-interface interaction energy due to the solute motion has been argued to be the origin for this slow solvation component as DR measurements do not indicate the presence of qualitatively similar relaxation time scale in the medium.

Studies of Poly(L-lactic acid) Composites: Influence of 1H-Benzotriazole on Thermal and Mechanical Performance in Matrix

This study reported the effect of the functional additive 1H-benzotriazole (BTA) on the thermal behaviour and mechanical properties of Poly(L-lactic acid) (PLLA) through differential scanning calorimeter (DSC), infrared spectra (IR), thermogravimetric analysis (TGA) and tensile testing. The DSC measurement showed that both BTA and cooling rate greatly affected the crystallization process of PLLA, the introduction of BTA leaded to a positive effect on promoting PLLA’s crystallization, but an increase of a cooling rate was negative. Compared with other concentration of BTA, 0.5 wt% BTA had the best crystallization accelerating effect. Second, thermal decomposition indicated that the onset decomposition temperatures of all PLLA/BTA composites were higher than that of BTA at same heating rate; as well as the onset decomposition temperature of BTA increased with increasing of the heating rate. Third, the mechanical performance showed that PLLA/BTA samples presented the irregular trend in the elongation at break with increasing of BTA content, and the PLLA/3%BTA had the maximum value 2.87%.

Polystyrene with Persistently Enhanced Fluorescence: Photo‐Induced Atom Transfer Radical Polymerization Using a Pyrene‐Based Initiator

AbstractThe pyrene‐based atom transfer radical polymerization (ATRP) initiator of 1‐pyrenemethyl 2‐bromoisobutyrate (PMBriB) was applied to the photo‐induced radical polymerization of methyl acrylate, methyl methacrylate, and styrene. During the polymerization, the fluorescence of the polymer solution caused by the chain end pyrene group was observed to be slightly enhanced in all cases, possibly due to the decline of the aggregation caused quenching (ACQ) effect. However, the fluorescence of polystyrene obtained from photo‐induced ATRP was significantly increased. Differential scanning calorimeter (DSC) measurements, NMR spectroscopy, and fluorescence measurements associated with a series of control studies demonstrated that the enhanced fluorescence was a persistent phenomenon in both solution and the solid state but the polystyrenes with and without enhanced fluorescence showed no observable difference in chemical bonding and molecular conformation. At this stage, the coexistence of pyrene, 2‐bromoisobutyrate group, styrene, and light was required for this novel phenomenon and the mechanism of this fluorescence enhancement is still being studied.

Fully Isotactic Poly(p-methylstyrene): Precise Synthesis via Catalytic Polymerization and Crystallization Studies

The synthesis of stereoregular styrenic polymers on single-site catalysts has received great attention over the last decades; however, little is known with respect to tailoring fully isotactic poly(p-methylstyrene) (iPpMS). Here, we demonstrate that isospecific coordination polymerization of p-methylstyrene can be achieved in the presence of the catalyst dichloro[1,4-dithiabutanediyl-2,20-bis(4,6-di-tert-butyl-phenoxy)]titanium activated by methylaluminoxane. Moreover, iPpMS has been assumed to be noncrystallizable for decades, as X-ray diffraction and differential scanning calorimeter measurements of powder samples failed to reveal a well-defined crystal structure. However, we successfully generated dendritic crystals of iPpMS from dilute solutions by carefully controlling the evaporation rate of the solvent. The crystal morphology was studied by optical microscopy and atomic force microscopy. In situ heating experiments of dendritic crystals allowed us to measure the melting temperature of iPpMS crystal...

The influence of reagents ball milling on the lithium ferrite formation

In this work, the effect of ball milling of Li2CO3 and Fe2O3 reagents on the Li0.5Fe2.5O4 ferrite formation was studied by thermogravimetric and differential scanning calorimetric measurements using non-isothermal heating and cooling modes. In the latter case, the analysis was carried out with a magnetic field applied in order to estimate the Curie temperature of the synthesized ferrite. The mechanical milling of both individual Li2CO3/Fe2O3 reagents and their mixture was performed with an AGO-2C planetary mill using steel vials and balls. Samples with different bulk densities, which were compacted from non-milled and milled powders by pressing with different compaction pressures, were investigated. The results showed that the mechanical milling of powder reagents separately does not cause a significant change in the reactivity of the ferrite system. Only milling of the Li2CO3/Fe2O3 mixture makes it possible not only to increase the reactivity of powders, but also to exclude additional compaction of samples before synthesis.

Determination of thermodynamic properties of the ternary oxides in the Y-Ru-O system by electromotive force measurements and differential scanning calorimetric measurements

In this study, the standard molar Gibbs energy of formation of Y2Ru2O7(s) and Y3RuO7(s) was determined using calcia-stabilized zirconia (CSZ) as an electrolyte and air as a reference electrode. The cells can be represented by: (−)Pt/{Y2O3(s) + Y2Ru2O7(s) + Ru(s)}//CSZ//O2(p(O2) = 21.21 kPa)/Pt(+), (−)Pt/{Y3RuO7(s) + Y2Ru2O7(s) + Y2O3(s)}//CSZ//O2(p(O2) = 21.21kPa)/Pt(+). The electromotive force was measured in the temperature range from 981 to 1155 K and 932 to 1186 K, respectively. The standard molar Gibbs energy of formation of Y2Ru2O7(s) and Y3RuO7(s) from elements in their standard state was calculated by the least squares regression analysis of the data obtained in the present study and can be given, respectively, by: {ΔfG(Y2Ru2O7, s)/(kJmol−1) ± 2.22} = − 2554.1 + 0.625 ⋅ (T/K) and {ΔfG(Y3RuO7, s)/(kJmol−1) ± 2.45} = − 3249.5 + 0.635 ⋅ (T/K). The standard molar heat capacity Cop,m(T) of Y2Ru2O7(s) was measured using a heat flux–type differential scanning calorimeter (DSC) in the temperature range, from 307 to 780 K. The heat capacity was fitted into a mathematical expression and can be represented by: Cp, m(Y2Ru2O7, s, T)(JK−1mol−1) = 256.1 + 5.88 ∙ 10−2T(K) − 34.75 ∙ 105/T2(K). (307 ≤ T (K) ≤ 780). The heat capacity of Y2Ru2O7(s) was used along with the data obtained from the electrochemical cell to determine its decomposition temperature and stability in air and to calculate other thermodynamic parameters.

Structural control and characterization of hierarchically structured fibrous scaffolds

To prepare hierarchically structured fibrous scaffolds with different morphologies, and to explore the additional dimensionality for tuning the physicochemical properties of the scaffolds and the effect of their hemocompatibility and cytocompatibility. Electrospinning poly (e-caprolactone) (PCL)/polyvinylpyrrolidone (PVP) bicomponent fibers (PCL∶PVP mass ratios were 8∶2 and 5∶5 respectively), and the surface porous fibrous scaffolds were prepared by extracting PVP components. The scaffolds were labeled PCL-P8 and PCL-P5 respectively according to the mass ratio of polymer. In addition, shish-kebab (SK) structured scaffolds with different kebab sizes were created by solution incubation method, which use electrospun PCL fibers as shish while PCL chains in solution crystallizes on the fiber surface. The PCL fibrous scaffolds with smooth surface was established as control group. The hierarchically structured fibrous scaffolds were characterized by field emission scanning electron microspore, water contact angle tests, and differential scanning calorimeter (DSC) experiments. The venous blood of New Zealand white rabbits was taken and hemolysis and coagulation tests were used to characterize the blood compatibility of the scaffolds. The proliferation of the pig iliac artery endothelial cell (PIEC) on the scaffolds was detected by cell counting kit 8 (CCK-8) method, and the biocompatibility of the scaffolds was evaluated. Field emission scanning electron microscopy showed that porous morphology appeared on the surface of PCL/PVP bicomponent fibers after extracting PVP. In addition, SK structure with periodic arrangement was successfully prepared by solution induction, and the longer the crystallization time, the larger the lamellar size and periodic distance. The contact angle and DSC measurements showed that when compared with smooth PCL fiber scaffolds, the crystallinity of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds increased, while the hydrophobicity of PCL-SK fibrous scaffolds increased, but the hydrophobicity of PCL porous scaffolds did not change significantly. The hemolysis test showed that the hemolysis rate of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds was higher than that of PCL fibrous scaffolds. According to American Society of Materials and Tests (ASTM) F756-08 standard, all scaffolds were non-hemolytic materials and were suitable for blood contact materials. Coagulation test showed that the coagulation index of PCL surface porous fibrous scaffolds and PCL-SK fibrous scaffolds was higher than that of PCL fibrous scaffolds at 5 and 10 minutes of culture. CCK-8 assay showed that both hierarchically structured fibrous scaffolds were more conducive to PIEC proliferation than PCL fibrous scaffold. Based on electrospinning technology, solution-induced and blend phase separation methods can be used to construct multi-scale fiber scaffolds with different morphologies, which can not only regulate the surface physicochemical properties of the scaffolds, but also have good blood compatibility and biocompatibility. The hierarchically structured fibrous scaffolds have high application potential in the field of tissue engineering.

Spectroscopic, textural, electrical and magnetic properties of antimicrobial nano Fe(III) Schiff base complex

A novel Schiff base ligand (L) was prepared through condensation of 2,6‐diaminopyridine and dibenzoyl methane in a 1:1 ratio. This Schiff base ligand was used for complex formation reaction with Fe(III) chloride. The structures of the ligand and its complex were deduced from elemental analyses, mass spectroscopy, 1H NMR, IR, UV‐Vis, electronic spectra, magnetic moment, molar conductivity measurements, thermogravimetric analyses and X‐ray diffraction. The molecular and electronic structures of both ligand and complex were optimized theoretically using density function theory (DFT) method. Moreover, the antimicrobial activities of the prepared compounds were studied and proven against some pathogenic bacteria. The Fe(III) complex had higher biological activity than that of the free ligand. Proceeding from the collected information, the properties of the complex were further investigated. The particle size was determined by dynamic light scattering technique to be 92.59 nm. Textural properties of the nano complex were studied by N2 adsorption to estimate the specific surface area, pore volume and pore size distribution. The pores in the complex were found in the micropore–mesopore range. Differential scanning calorimetric measurements reveal the existence of four endothermic peaks at 243.8, 308, 339.8 and 380.5 K. Dielectric properties and conductivity were scanned at different frequencies and temperatures. The dielectric constant reaches a peak value of 600 at ~390 K, 30 Hz. A cross‐over from the universal dielectric response to the super linear power law of conductivity was reported for this complex at T ≤ 345 K. Finally, the AC‐magnetic susceptibility measurements were carried out in the low‐temperature region. The complex showed paramagnetic behavior with a slight change in the magnitude of its magnetic moment at T = 244 K.

Microencapsulated -octadecane with TiO2-doped silk fibroin shell for thermal energy storage and UV-shielding

The novel microencapsulated n-octadecane with TiO2-doped silk fibroin (SF) shell was synthesized using a self-assembly method in o/w emulsion. It was confirmed by Fourier transformation infrared spectroscope (FT-IR) and a three-phase contact angle that TiO2 is successfully modified by SF aqueous solution. The scanning electronic microscope (SEM) and laser scattering particle size distribution analyzer showed that the as-prepared microcapsules have regularly spherical morphology and are about 4–5 μm in average diameter. According to differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA) and ultraviolet visible spectrophotometer (UV–vis) measurements, the TiO2-doped microcapsule presents high thermal storage capability, enhanced thermal reliability and stability, and have good UV-shielding property. The TiO2-doped microcapsule synthesized in the present study could prove to be path-breaking and lead to further studies in the field of thermal energy storage and UV-shielding applications.