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Bryan Merrill posted an update 6 months, 3 weeks ago
The ionic conductivity of GPGPEs with 20 wt % star polymer and 1.5 wt % gelator was importantly improved at high temperatures (6.02 mS cm-1 at 80 °C). We systematically investigated the electrochemical performances of PGPEs without star polymer, PGPEs with star polymer, and GPGPEs with star polymer. The incorporation of star polymers with linear PEG arms and cycloPEG cores into the PGPEs and GPGPEs significantly improved the electrochemical performances of the lithium metal/LiFePO4 cell assembled with the PGPEs or GPGPEs.The internal dynamics during the axisymmetric coalescence of an initially static free droplet and a sessile droplet of the same fluid are studied using both laboratory experiments and numerical simulations. A high-speed camera captured internal flows from the side, visualized by adding a dye to the free droplet. The numerical simulations employ the volume of fluid method, with the Kistler dynamic contact angle model to capture substrate wettability, quantitatively validated against the image-processed experiments. It is shown that an internal jet can be formed when capillary waves reflected from the contact line create a small tip with high curvature on top of the coalesced droplet that propels fluid toward the substrate. Jet formation is found to depend on the substrate wettability, which influences capillary wave reflection; the importance of the advancing contact angle subordinated to that of the receding contact angle. It is systematically shown via regime maps that jet formation is enhanced by increasing the receding contact angle and by decreasing the droplet viscosity. Jets are seen at volume ratios very different from those accepted for free droplets, showing that a substrate with appropriate wettability can improve the efficiency of fluid mixing.It is of both practical and scientific significance to understand the temperature dependence of contact angles of water on various surfaces. However, the variation trend of water wettability on a smooth hydrophobic surface with increasing temperature remains unclear. In this work, in situ characterization of the contact angle of water on Teflon (polytetrafluoroethylene) surfaces and the interfacial tension of water over a temperature spectrum from ∼25 to 160 °C under pressurized conditions (2, 3, and 5 MPa) in a nitrogen atmosphere was conducted by employing the sessile drop and pendant drop methods, respectively. A nearly invariant trend of the contact angle was observed over the entire temperature and pressure range. As expected, however, it was shown that the water-N2 interfacial tension almost linearly declines with increasing temperature and that pressure has a negative effect on the interfacial tension. Based on the theory of surface thermodynamics, the effects of temperature on the contact angles were analyzed in combination with the gas adsorption effect. Estimations on the solid-gas interfacial tension, surface entropy, and the heat of immersion were made to gain more insights into the temperature dependence of the water contact angle on a smooth hydrophobic surface.Synthesis of hollow polydopamine bowl-shaped nanoparticles (nanobowls), as small as 80 nm in diameter, via a one-pot template-free rapid method is reported. Addition of dopamine to a solution of 0.606 mg/mL tris(hydroxymethyl)aminomethane in an ethanol/water mixed solvent resulted in the formation of hollow spherical nanocapsules within 2 h. At longer reaction times, the formation of conventional solid nanospheres dominated the reaction. The wall thickness of the nanocapsules increased with increasing dopamine concentration in the reaction medium. Wall thickness was also influenced by oxygen availability during the reaction. Nanocapsules with thin walls were prone to collapse. When dried, over 90% of the nanocapsules with wall thickness on the order of 11 nm collapsed. https://www.selleckchem.com/products/ertugliflozin.html Also, the degree of collapse of individual nanoparticles changed from complete to partial to no collapse as the wall thickness was increased. Varying the ethanol content affected the cavity size and overall dimension of the nanocapsules produced but did not result in a significant change to the wall thickness. A mechanism describing the formation of the nanocapsules and their subsequent collapse into nanobowls is presented. The shape-tunable nanobowls prepared through this green, rapid, and affordable method are expected to have applications in the biomedical, electrochemical, and catalytic fields.Understanding the interactions of soft nanomatters with cell membranes is particularly important for research into nanocarrier-based drug delivery systems, cell engineering, and subcellular imaging. Most nanoparticles, vesicles, micelles, and polymeric aggregates are internalized into endosomes and, eventually, lysosomes in the cytosol because of energy-dependent endocytic processes. Endocytic uptake substantially limits the access to the cytoplasm where a cargo agent acts. Bypassing the endocytic pathways by direct penetration into plasma membrane barriers would enhance the efficacy of nanomedicines. Some zwitterionic polymer nanoaggregates have been shown to permeate into the cell interior in an energy-independent manner. We have elucidated this phenomenon by observing changes in the biomembrane barrier functions against protons as the smallest indicator and have used these results to further design and develop poly(betaines). In this work, we investigated the translocation mechanisms for a series of zwitterionic poly(methacrylamide) and poly(methacrylate) species bearing a pyridinium propane sulfonate moiety in the monomers. Minor differences in the monomer structures and functional groups were observed to have dramatic effects on the interaction with plasma membranes during translocation. The ability to cross the plasma membrane involves a balance among the betaine dipole-dipole interaction, NH-π interaction, π-π interaction, cation-π interaction, and amide hydrogen bonding. We found that the cell-penetrating polysulfobetaines had limited or no detrimental effect on cell proliferation. Our findings enhance the opportunity to design and synthesize soft nanomatters for cell manipulations by passing across biomembrane partitions.
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