超浸润形状记忆海绵的制备及油-水分离性能

基于反式 1,4-聚异戊二烯(TPI)的形状记忆性能, 以聚氨酯海绵为基底, 包覆TPI制备出了一种具有疏水超亲油特性的三维多孔形状记忆海绵. 由于这种海绵具有良好的形状记忆特性, 可以通过反复按压/恢复过程, 实现对海绵孔径在微米尺寸(约875 μm)与纳米尺寸(约450 nm)间可逆调控. 利用材料特殊的浸润特征及其可控的孔尺寸, 进一步研究了其在油-水分离中的应用. 研究结果表明, 微米尺寸大孔径海绵有利于对不相溶油-水混合物进行快速高效分离, 而纳米尺寸小孔径海绵则有利于对乳液混合物进行分离, 实现了同一材料同时满足不相溶油-水混合物及乳液体系的分离要求.     

A Molecular Photosensitizer in a Porous Block Copolymer Matrix-Implications for the Design of Photocatalytically Active Membranes

Recently, porous photocatalytically active block copolymer membranes were introduced, based on heterogenized molecular catalysts. Here, we report the integration of the photosensitizer, i. e., the light absorbing unit in an intermolecular photocatalytic system into block copolymer membranes in a covalent manner. We study the resulting structure and evaluate the orientational mobility of the photosensitizer as integral part of the photocatalytic system in such membranes. To this end we utilize transient absorption anisotropy, highlighting the temporal reorientation of the transition dipole moment probed in a femtosecond pump-probe experiment. Our findings indicate that the photosensitizer is rigidly bound to the polymer membrane and shows a large heterogeneity of absolute anisotropy values as a function of location probed within the matrix. This reflects the sample inhomogeneity arising from different protonation states of the photosensitizer and different intermolecular interactions of the photosensitizers within the block copolymer membrane scaffold.     

Ferrimagnetic behaviors in a double-wall cubic metal nanotube

A double-wall cubic metal nanotube consists of the ferromagnetic spin-1 inner shell and spin-3/2 surface shell. It is of the ferrimagnetic exchange coupling between two shells. Considering the single-ion anisotropy and transverse field exist together, the magnetization, the initial susceptibility, the internal energy and the specific heat have been investigated by using the effective-field theory with correlations. Some interesting phenomena have been found in the thermal variations of the system. Magnetization appears two or three compensation points in certain parameters. It is an unconventional ferrimagnetic behavior in the nanotube. The shapes of total magnetization and the initial susceptibility are great influenced by the surface exchange coupling, surface single-ion anisotropy and surface transverse field. Some results of nanotube may have potential applications in different research fields, such as electronics, optics, mechanics, and even biomedicine and molecular devices.     

Unravelling the Relationship between Raman Enhancement and Photocatalytic Activity on Single Anisotropic Au Microplates

Anisotropic noble‐metal structures are attracting increasing attention because of interesting size‐ and shape‐dependent properties and have emerging applications in the fields of optics and catalysis. However, it remains a significant challenge to overcome chemical contributions and acquire molecular insight into the relationship between Raman enhancement and photocatalytic activity. This study gives visualized experimental evidence of the anisotropic spatial distribution of Raman signals and photocatalytic activity at the level of single nanometer‐thin Au microtriangles and microhexagons. Theoretical simulations indicate an anisotropic spatial distribution and sharpness‐dependent strength of the electric‐field enhancement. Analysis by using statistical surface‐enhanced Raman scattering (SERS) supports this view, that is, Raman enhancement is on the order of corner>edge>face for a single microplate, but SERS measurements at different depths of focus also imply a concentration‐dependent feature of SERS signals, especially at the corners and edges. Similarly, the SERS signals of product molecules in plasmonic photocatalysis also exhibit asymmetrical strengths at different corners of the same microplate. However, by examining the variations in the relative intensities of the SERS peaks, the difference in the photocatalytic activities at the corners, edges, and faces has been successfully calculated and is highly consistent with electric‐field simulations, thus indicating that an increased number of molecules adsorbed at specific sites does not necessarily lead to a higher conversion ratio in noble‐metal photocatalysis. Our strategy weakens the assumed impact of plasmonic local heating and, to a certain extent, excludes the influence of concentration effects and chemical contributions in noble‐metal photocatalysis, thus clearly profiling plasmon‐related characteristics. This study also promises a new research direction to understand the enhancement mechanism of SERS‐active structures.     

Photoresponding ionic complex containing azobenzene chromophore for use in birefringent flm简

A novel photoresponding ionic complex （PANDAZO） was prepared by the ionic self-assembly （1SA） of sodium polyacrylate （PANa） and azobenzene chromophores （NDAZO）. The ionic complex forms an interdigitated lamellar structure with full overlap of the side chains. The optical anisotropy was investigated by using a polarization pulse laser （355 nm）. Furthermore, a high photoinduced birefringence （An = 0.365） was measured by using a continuous 488 nm laser as the pump light.     

Thermodynamic and shape memory properties of TPI/HDPE hybrid shape memory polymer

The traditional processing technology of shape memory polymer composites is complex and the cost of high performance filler is high. Therefore, low-cost high density polyethylene (HDPE) was introduced into trans-1,4-polyisoprene (TPI) matrix as reinforcing phase, and a novel shape memory polymer was prepared by mechanical melt blending, which fully exerted the excellent properties of plastic and rubber. Because of the difference in molecular chain distribution between different blend ratios of TPI/HDPE hybrid SMPCs specimens, the change of the blend ratio of the two components affects the thermodynamic and shape memory properties of the SMPCs. A series experimental results show that the TPI/HDPE hybrid SMPCs with the blend ratio of 80/20 has excellent thermodynamic and shape memory properties. And we believe that the relevant conclusions of this study can provide valuable design reference for the development of high-performance TPI SMPCs.     

Mononuclear High-spin Octahedral Cobalt(II) Complex with Positive Axial Magnetic Anisotropy: Synthesis,Crystal Structure,and DFT Studies

This article outlines the magnetic features of a new six–coordinate high-spin cobalt(II) complex cis-[Co^II(tmphen)₂(NCS)₂] ( 1 ) achieved via the reactions of cobalt(II) thiocyanate with 3,4,7,8-tetramethyl-1,10-phenanthroline. The complex 1 was thoroughly characterized by different analytical and spectroscopic techniques and further confirmed by single X-ray crystal diffraction pattern. Complex 1 is a neutral molecule and adopt highly distorted six-coordinate CoN₆ octahedral coordination sphere surrounded by two thiocyanate N atoms in cis locations and the equatorial plane is occupied by two imine N atoms from the two tmphen ligand while the remaining two imine N atoms reside in the axial positions. Magnetic susceptibility data of complex 1 revealed that the χ_ΜT values decrease significantly to a value of 1.49 cm³ · K · mol^–1 at 2.0 K on decreasing temperatures below 100 K, mainly ascribed to the significant spin–orbit coupling (SOC) of six-coordinate Co^II ions. Furthermore, a field-dependence measurement was performed at 2 K, which shows a positive curvature up to 27 kOe, while it becomes linear up to 2.01 Nμ_B, which authenticated the fact that only the lowest Kramers doublet of ground state is appreciably populated.     

Preparation of body-temperature-triggered shape-memory polyurethane with biocompatibility using isosorbide and castor oil

Shape memory polyurethanes (SMPUs) have attracted much attention in the biomedical field because they can easily control the transition temperature (T_trans) to shape memory and are biocompatible. In this study, a shape memory polyurethane with both biocompatibility and a T_trans close to the body temperature was synthesized by using natural derivatives of isosorbide and castor oil in place of petroleum-based materials. Isosorbide and castor oil were used to form net points, and polycaprolactone diol (PCL diol) acted as the switching segment. The synthesized four polyurethane (PCL diol/isosorbide/castor oil, PICU-1, 2, 3, 4) with different isosorbide contents exhibited desired thermal and mechanical properties. In the thermo-cyclic shape memory testing experiment, the PICU series demonstrated good shape memory property, with more than 95% shape recovery ratio (R_r) and more than 90% shape fixity ratio (R_f), and PICU-3 recovered its shape within 20 s in a 37 °C water bath. In addition, the PICU series proved to be safe materials with excellent biocompatibility, as indicated by the observed C2C12 cells viability and proliferation. The stent made with the PICU-3 film showed near complete magnetization at 37 °C within 18 s and proved to be a suitable self-expanding stent.     

根据角度节面及其对称性分布导出原子轨道形状

The shape of an atomic orbital not only depends on the azimuthal quantum number l, but also associates with the magnetic quantum number m. We discussed about how to derive the shape of an atomic orbital from the numbers and shapes of the angular nodal planes, and the symmetries of distribution of all angular nodal planes when l and|m|are known. According to the|m|, the compatibility of the symmetry of an atomic orbitals have also been also discussed.