Control Sub729

EEG and ET mat format data of one control student Sub729 in ABT and CCT experiments

Enabling High Quality Factor and Enhanced Thermoelectric Performance in BiBr₃‑Doped Sn_0.93Mn_0.1Te via Band Convergence and Band Sharpening

Lead-free SnTe-based materials are expected to replace PbTe and have gained much attention from the thermoelectric community. In this work, a maximum ZT of ∼1.31 at 873 K is attained in SnTe via promoting a high quality factor resulting from Mn alloying and BiBr3 doping. The results show that Mn alloying in SnTe converges the L band and the ∑ band in valence bands to supply enhanced valley degeneracy and the density of states effective mass, giving rise to a high power factor of ∼21.67 μW cm–1 K–2 at 723 K in Sn0.93Mn0.1Te. In addition, the subsequent BiBr3 doping can sharpen the top of the valence band to coordinate the contradiction between the band effective mass and the carrier mobility, thus enhancing the carrier mobility while maintaining a relatively large density of states effective mass. Consequently, a maximum power factor of 23.85 μW cm–1 K–2 at 873 K is achieved in Sn0.93Mn0.1Te-0.8 atom % BiBr3. In addition to band sharpening, BiBr3 doping can also effectively suppress the bipolar effect at elevated temperatures and reduce the lattice thermal conductivity by strengthening the point defect phonon scattering. Benefitting from doping BiBr3 in Sn0.93Mn0.1Te optimizes the carrier mobility and suppresses the lattice thermal conductivity, resulting in a dramatically enhanced quality factor. Accordingly, an average ZT of ∼0.62 in the temperature range of 300–873 K is obtained in Sn0.93Mn0.1Te-0.8 atom % BiBr3, ∼250% increase compared with that in Sn1.03Te

Effect of PEO-PPO-ph-PPO-PEO and PPO-PEO-ph-PEO-PPO on the Rheological and EOR Properties of Polymer Solutions

The rheological properties of partially hydrolyzed polyacrylamide (HPAM) and PEO-PPO-ph-PPO-PEO (BPE) or PPO-PEO-ph-PEO-PPO (BEP) block polyether solutions are investigated here. Another hydrophobically associating polymer (HMPAM) is chosen as a contrast. The rheological results show that the elastic modulus (G′) and viscous modulus (G″) of HPAM/BPE and HPAM/BEP solutions first increase then decrease, while the viscosities of HMPAM/BPE and HMPAM/BEP solutions decrease with the increase of block polyether concentration. The HPAM/BPE solution has a larger viscosity than HPAM/BEP, while the HMPAM/BPE solution has a lower viscosity than HMPAM/BEP. The polymer solutions containing BEP have larger G′ and G″ values than the solutions with BPE. Furthermore, the block polyethers reduce the sensitivity of viscosity to temperature. BEP is more effective to stabilize the viscoelastic property and improve the temperature resistance than BPE in HMPAM system. BEP has a better property to enhance the salt tolerance of the polymer solution than BPE. Moreover, the enhanced oil recovery (EOR) experiments show that HPAM/block polyether mixed solution has a larger oil recovery than HPAM, and HPAM/BEP system has a larger enhanced effect than HPAM/BPE solution

Surface Tension and Dilational Viscoelasticity of Water in the Presence of Surfactants Tyloxapol and Triton X-100 with Cetyl Trimethylammonium Bromide at 25 °C

Surface tension and dilational viscoelasticity of water in the presence of surfactants Tyloxapol and Triton X-100 with cetyl trimethylammonium Bromide (CTAB) at 25 °C are investigated. The results show that there is synergistic behavior in both the mixtures at higher mole fraction of nonionic surfactant. According to the Rubingh and Rosen theory, the results predict nonideal mixing and attractive interaction between the constituent surfactants in the mixed micelle and layer. By using the Maeda theory, the results suggest the chain−chain interaction among surfactants does not seem to be high. The surface dilational viscoelasticity results show that the Tyloxapol adsorption layer has the highest dilational modulus |ε| value among three single surfactants. Also, it indicates the |ε| maximum values of surfactant mixtures are usually between that of the single surfactant. Moreover, it is worth noting that the |ε| maximum values of Tyloxapol/CTAB mixtures are always higher than those of TX-100/CTAB ones

Molecular Dynamics Simulations of SDS, DTAB, and C₁₂E₈ Monolayers Adsorbed at the Air/Water Surface in the Presence of DSEP

The properties of adsorbed monolayers of three hydrocarbon surfactants with the same hydrophobic tail, sodium dodecyl sulfate (SDS), dodecyltrimethylammonium bromide (DTAB) and octaethylene glycol dodecyl ether (C12E8) at the air/water surface in the absence and presence of a dimethylsiloxane ethoxylate-propoxylate (DSEP) were studied via molecular dynamics simulations to compare the effect of the headgroups on the aggregation behaviors of surfactant mixtures. The structures and dynamical properties of the monolayers were greatly affected after adding DSEP. In the presence of DSEP, SDS monolayer was better ordered and more compact, whereas C12E8 monolayer was relatively disordered. Some DTAB molecules immerged into water, and the others adsorbed at the surface were in less compact but well-ordered arrangement. The reason for the appearance of different types of monolayers was also discussed, with the goal of providing a theoretical approach for their further applications

Manipulation of the Gel Behavior of Biological Surfactant Sodium Deoxycholate by Amino Acids

Supramolecular hydrogels were prepared in the mixtures of biological surfactant sodium deoxycholate (NaDC) and halide salts (NaCl and NaBr) in sodium phosphate buffer. It is very interesting that with the addition of two kinds of amino acids (l-lysine and l-arginine) to NaDC/NaX hydrogels, the gel becomes solution at room temperature. We characterized this performance through phase behavior observation, transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectra, and rheological measurements. The results demonstrate that the gels are formed by intertwined fibrils, which are induced by enormous cycles of NaDC molecules driven by comprehensive noncovalent interactions, especially the hydrogen bonds. Our conclusion is that the presence of halide salts (NaCl and NaBr) enhances the formation of the gels, while the addition of amino acids (l-lysine and l-arginine) could make the breakage of the hydrogen bonds and weaken the formation of the gels. Moreover, its fast disassembly in the presence of amino acids allows for the release of substances (i.e., the dye methylene blue) entrapped within the gel network. The tunable gel morphology, microstructure, mechanical strength, and anisotropy verify the role of halide salts and amino acids in altering the properties of the gels, which can probably be exploited for a variety of applications in future

Effect of Amino Acids on Aggregation Behaviors of Sodium Deoxycholate at Air/Water Surface: Surface Tension and Oscillating Bubble Studies

The aggregation behaviors of sodium deoxycholate (NaDC) at the air/water surface were investigated via surface tension and oscillating bubble measurements in the absence and presence of three alkaline amino acids, namely, l-Lysine (l-Lys), l-Arginine (l-Arg), and l-Histidine (l-His). The results of surface tension measurements show that NaDC has a lower ability to reduce the surface tension of water, because NaDC molecules orient at the surface in an oblique direction and tend to aggregate together, which is approved by molecular dynamics (MD) simulation. l-Lys is the most efficient of the three amino acids in reducing the critical aggregation concentration (cac) of NaDC in aqueous solution. The influence of amino acids on the dilational rheological properties of NaDC was studied using the drop shape analysis method in the frequency range from 0.02 to 0.5 Hz. The results reveal that the absolute modulus passes through a maximum value with increasing NaDC concentration. The addition of amino acids increases the absolute modulus of NaDC, and the maximum value is observed at much lower concentration. From the perspective of structures of amino acids, the performance of l-Arg is similar to that of l-His, and both of them bring out a smaller effect on the absolute modulus than that of l-Lys. From the above results, it may be presumed that electrostatic and hydrophobic effects are important impetus during the interaction between amino acids and NaDC at the air/water surface. Hydrogen bonding is so ubiquitous in the system that the difference of hydrogen bonding between NaDC and amino acid is ignored

Transcriptive Synthesis of Mg(OH)₂ Hollow Nanospheres and the Non-Equilibrium Shell Fusion Assisted by Catanionic Vesicles

The oriented attachment of inorganic nanocrystals controlled by adsorbed surfactants can lead to the formation of hollow nanoarchitectures with various well-defined morphologies. In this paper, Mg(OH)2 hollow nanospheres and the “encapsulated” catanionic vesicles could be simultaneously constructed by using the cationic surfactant of cetyltrimethylammonium hydroxide (CTAOH) and the anionic surfactant of magnesium dodecyl sulfate (Mg(DS)2) as reactants at pH 11.0. Therein, the driven forces for the oriented attachment of Mg(OH)2 particles should involve hydrophobic interactions among pendent surfactants. Similarly, the secondary architectures derived from catanionic surfactant−Mg(OH)2 hollow nanospheres could also be encountered under nonequilibrium conditions. Interestingly, the coating of Mg(OH)2 particles facilitated the direct observation of nanosized surfactant self-assemblies and the membrane fusion without using general staining methods. After the crystalline fusion of coating particles, Mg(OH)2 hollow nanospheres and the correspondingly shell-fused superstructures were obtained, implying a simple and versatile method for the study of lipid membranes and the fabrication of M(OH)2 (M = divalent metal ions) hollow architectures

Aggregation Behaviors of PEO-PPO-ph-PPO-PEO and PPO-PEO-ph-PEO-PPO at an Air/Water Interface: Experimental Study and Molecular Dynamics Simulation

The block polyethers PEO-PPO-ph-PPO-PEO (BPE) and PPO-PEO-ph-PEO-PPO (BEP) are synthesized by anionic polymerization using bisphenol A as initiator. Compared with Pluronic P123, the aggregation behaviors of BPE and BEP at an air/water interface are investigated by the surface tension and dilational viscoelasticity. The molecular construction can influence the efficiency and effectiveness of block polyethers in decreasing surface tension. BPE has the most efficient ability to decrease surface tension of water among the three block polyethers. The maximum surface excess concentration (Γ_max) of BPE is larger than that of BEP or P123. Moreover, the dilational modulus of BPE is almost the same as that of P123, but much larger than that of BEP. The molecular dynamics simulation provides the conformational variations of block polyethers at the air/water interface

Fabrication of Smart pH-Responsive Fluorescent Solid-like Giant Vesicles by Ionic Self-Assembly Strategy

A fluorescent solid-like giant vesicle was prepared by using an anionic dye methyl orange (MO) and an oppositely charged surfactant 1-tetra­decyl-3-methyl­imida­zolium bromide (C₁₄mimBr) on the basis of the ionic self-assembly (ISA) strategy. The properties of MO/​C₁₄mim­Br complexes were comprehensively characterized. The results indicated that the giant vesicle was formed by the fusion of small vesicles and could keep its original structure during the evaporation of solvent. Besides, the giant vesicles exhibit luminescent property owing to the break of intermolecular π–π stacking of MO, which achieves the transformation from aggregation-caused quenching to aggregation-induced emission by noncovalent interaction. Moreover, MO/​C₁₄mim­Br complexes also exhibit smart pH-responsive characteristics and abundant thermic phase behavior. That is, various fluorescent structures (polyhedron, giant vesicle, chrysanthemum, peony-like structure) were obtained when pH ≥ 4, whereas a simple nonfluorescent structure (microflake) was obtained when pH = 2 due to the changes of MO configuration. Thus, the fluorescence behavior can be predicted with the color change directly visible to the naked eye by changing the pH. It is expected that the facile and innovative design of supramolecular material by the ISA strategy could be used as pH detection probes and microreactors