Catalyst Control of Interfacial Welding Mechanical Properties of Vitrimers

Chinese Journal of Polymer Science - Interfacial welding of thermosetting polymers has been a challenge, but vitrimers with dynamic covalent networks open numerous opportunities for welding and...     

Grain size engineering and growth mechanism in hydrothermal synthesis of Bi0.5Na0.5TiO3 thin films on Nb-doped SrTiO3 substrates

Journal of Sol-Gel Science and Technology - Considering the full utilization of energy and pursuing thin-film capacitors with high energy-storage density, the grain size engineering is used to...     

Finite particle number description of neutron matter using the unitary correlation operator and high-momentum pair methods

Using bare Argonne V4' (AV4'), V6' (AV6'), and V8' (AV8') nucleon–nucleon (\begin{document}$NN$\end{document}) interactions, the nuclear equations of state (EOSs) for neutron matter are calculated with the unitary correlation operator and high-momentum pair methods. Neutron matter is described using a finite particle number approach with magic number \begin{document}$N=66$\end{document} under a periodic boundary condition. The central short-range correlation originating from the short-range repulsion in the \begin{document}$NN$\end{document} interaction is treated by the unitary correlation operator method (UCOM), and the tensor correlation and spin-orbit effects are described by the two-particle two-hole (2p2h) excitations of nucleon pairs, where the two nucleons with a large relative momentum are regarded as a high-momentum (HM) pair. With increasing 2p2h configurations, the total energy per particle of the neutron matter is well-converged under this UCOM+HM framework. Comparing the results calculated with AV4', AV6', and AV8' \begin{document}$NN$\end{document} interactions, we demonstrate the effects of the short-range correlation, tensor correlation, and spin-orbit coupling on the density dependence of the total energy per particle of neutron matter. Moreover, the contribution of each Hamiltonian component to the total energy per particle is discussed. The EOSs of neutron matter calculated within the present UCOM+HM framework agree with the calculations of six microscopic many-body theories, especially the auxiliary field-diffusion Monte Carlo calculations.     

Strain-Enhanced Metallic Intermixing in Shape-Controlled Multilayered Core–Shell Nanostructures: Toward Shaped Intermetallics

Controlling the surface composition of shaped bimetallic nanoparticles could offer precise tunability of geometric and electronic surface structure for new nanocatalysts. To achieve this goal, a platform for studying the intermixing process in a shaped nanoparticle was designed, using multilayered Pd-Ni-Pt core–shell nanocubes as precursors. Under mild conditions, the intermixing between Ni and Pt could be tuned by changing layer thickness and number, triggering intermixing while preserving nanoparticle shape. Intermixing of the two metals is monitored using transmission electron microscopy. The surface structure evolution is characterized using electrochemical methanol oxidation. DFT calculations suggest that the low-temperature mixing is enhanced by shorter diffusion lengths and strain introduced by the layered structure. The platform and insights presented are an advance toward the realization of shape-controlled multimetallic nanoparticles tailored to each potential application.     

Head–Tail Asymmetry as the Determining Factor in the Formation of Polymer Cubosomes or Hexasomes in a Rod–Coil Amphiphilic Block Copolymer

The self‐assembly of a rod–coil amphiphilic block copolymer (ABCP) led to Im m and Pn m polymer cubosomes and p6mm polymer hexasomes. This is the first time that these structures are observed in a rod–coil system. By varying the hydrophobic chain length, the initial concentration of the polymer solution, or the solubility parameter of the mixed solvent, head–tail asymmetry is adjusted to control the formation of polymer cubosomes or hexasomes. The formation mechanism of the polymer cubosomes was also studied. This research opens up a new way for further study of the bicontinuous and inverse phases in different ABCP systems.     

Random fixed points of set-valued operators

Some random fixed point theorems for set-valued operators are obtained. The measurability of certain marginal maps is also studied. The underlying measurable space is not assumed to be a Suslin family.

     

Coupling molecular rigidity and flexibility on fused backbones for NIR-II photothermal conversion

Great attention is being increasingly paid to photothermal conversion in the near-infrared (NIR)-II window (1000–1350 nm), where deeper tissue penetration is favored. To date, only a limited number of organic photothermal polymers and relevant theory have been exploited to direct the molecular design of polymers with highly efficient photothermal conversion, specifically in the NIR-II window. This work proposes a fused backbone structure locked via an intramolecular hydrogen bonding interaction and double bond, which favors molecular planarity and rigidity in the ground state and molecular flexibility in the excited state. Following this proposal, a particular class of NIR-II photothermal polymers are prepared. Their remarkable photothermal conversion efficiency is in good agreement with our strategy of coupling polymeric rigidity and flexibility, which accounts for the improved light absorption on going from the ground state to the excited state and nonradiative emission on going from the excited state to the ground state. It is envisioned that such a concept of coupling polymeric rigidity and flexibility will offer great inspiration for developing NIR-II photothermal polymers with the use of other chromophores.

Low bandgap and large deformation generally conflict each other. This work couples molecular rigidity and flexibility by intramolecular hydrogen bonds and double bonds to achieve NIR-II light absorption and reinforced internal conversion at the same time.     

Enhancement of frequency modulation response time for polymer-dispersed liquid crystal

Through the ferroelectric nanoparticles of BaTiO₃ (BTO) doping, the response time for the frequency modulation of the polymer-dispersed liquid crystal (PDLC) was improved. The BTO-doped PDLC cells were prepared by polymerisation induced phase separation (PIPS) process using UV light. The capacitance of the PDLC composites was measured with an impedance analyzer in the frequency range of 100 Hz–1 MHz at 1 V. The dynamic signal for the response time of the PDLC devices was monitored through a digital oscilloscope. The electro-optical properties of the PDLC were found to strongly depend on the doped BTO concentration. The BTO doping caused a large increase in the capacitance. The dielectric constants were drastically decreased in the samples with rather low BTO doping ratio at a high frequency. No outstanding difference in the rising time of the LC was observed in the BTO-doped PDLC device, but the falling time was significantly decreased from 0.334 to 0.094 s. The present results imply that the nanoparticle-doping technology could improve the electro-optical performance of the PDLC requiring fast response and frequency modulation, such as optical modulators and PDLC-hybrid electroluminescence device for flexible electronic devices.     

Fluoranthene removal in aqueous phase by Fe(II) activated sodium percarbonate: mechanisms and degradation pathways

Research on Chemical Intermediates - In this study, the removal performance and degradation mechanisms of fluoranthene (FLT) in sodium percarbonate (SPC) activated by Fe(II) system were...