Stretchable Self-Healing Polymeric Networks with Recyclability and Dual Responsiveness

Intelligent polymers with tough networks are of considerable significance for thedevelopment of highly proficient polymer science and technology. In this work, polymeric elastomers with integrated stretchable and self-healable characteristics were designed by cross-linking hyperbranched polymers with flexible segments. The hyperbranched polymer with multiple terminal groups provided various cross-linking points, so that mechanically robust networks could be achieved. Driven by the reversibility of imine and disulfide bonds employed, the elastomers exhibited good self-healing property and the healing efficiency reached up to 99% under ambient environments. Furthermore, the dynamic reversibility of the polymers was investigated at molecular level. The imine and disulfide bonds were incorporated into the networks to construct soluble and recyclable hyperbranched polymer with pH and redox responsiveness via A2+B3 approach and Schiff base polymerization. The polymers containing imine bonds could complete the polymerization–depolymerizationtransition and undergo reversible cycles for several times through changing pH. Moreover, in the presence of disulfide bonds, the polymers were provided with redox cleavage property triggered by dithiothreitol. This study may provide new opportunities for the design and application of intelligent polymers with tough networks through regulating topological structures

The intramolecular S = O···H-O hydrogen bond in a chiral cyclic sulfite ester: How it affects the reaction behavior and spectral properties

<p>The intramolecular S = O···H−O hydrogen bond in a chiral cyclic sulfite ester, which affects the reaction behavior and spectral properties considerably, was studied.</p

Improvement of E Se tea extracts on renal mesangial cell apoptosis and high-fat-diet/streptozotocin-induced diabetic nephropathy

E Se tea, the leaves of Malus toringoides (Rehd.) Hughes, is a kind of traditional beverage, which is often used to relieve hyperglycemia and hyperlipidemia and other symptoms, while its effect on diabetic nephropathy (DN) is still unclear. In this study, we evaluated the improvement of the ethanol extract of M. toringoides (EMT) on tert-butyl hydroperoxide (t-BHP)-induced rat glomerular mesangial cells (HBZY-1) apoptosis and high-fat-diet (HFD)/streptozotocin (STZ)-induced DN rats. The results showed that the EMT significantly reversed apoptosis, mitochondrial depolarization and cysteinyl aspartate specific proteinase (caspase) 3/9 activation in t-BHP (50 μM)-exposed HBZY-1 cells. Moreover, 8-weeks treatment of EMT improved blood glucose, proteinuria, serum creatinine and urea nitrogen, renal oxidative stress, proinflammatory mediators, histopathology and decreased activation of caspase 3. These results suggested that the E Se tea may therefore be a potential complementary therapy targeting DN patients

Broadband Achromatic Metasurfaces for Longwave Infrared Applications

Longwave infrared (LWIR) optics are essential for several technologies, such as thermal imaging and wireless communication, but their development is hindered by their bulk and high fabrication costs. Metasurfaces have recently emerged as powerful platforms for LWIR integrated optics; however, conventional metasurfaces are highly chromatic, which adversely affects their performance in broadband applications. In this work, the chromatic dispersion properties of metasurfaces are analyzed via ray tracing, and a general method for correcting chromatic aberrations of metasurfaces is presented. By combining the dynamic and geometric phases, the desired group delay and phase profiles are imparted to the metasurfaces simultaneously, resulting in good achromatic performance. Two broadband achromatic metasurfaces based on all-germanium platforms are demonstrated in the LWIR: a broadband achromatic metalens with a numerical aperture of 0.32, an average intensity efficiency of 31%, and a Strehl ratio above 0.8 from 9.6 μm to 11.6 μm, and a broadband achromatic metasurface grating with a constant deflection angle of 30° from 9.6 μm to 11.6 μm. Compared with state-of-the-art chromatic-aberration-restricted LWIR metasurfaces, this work represents a substantial advance and brings the field a step closer to practical applications

Bandpass Filter Integrated Metalens Based on Electromagnetically Induced Transparency

A bandpass filter integrated metalens based on electromagnetically induced transparency (EIT) for long-wavelength infrared (LWIR) imaging is designed in this paper. The bandwidth of the metalens, which is a diffractive optical element, decreases significantly with the increase of the aperture size to a fixed f-number, which leads to the decline of imaging performance. The same material composition and preparation process of the metalens and the EIT metasurface in the long-wavelength infrared make it feasible that the abilities of focusing imaging and filtering are integrated into a metasurface device. With the purpose of validating the feasibility of this design method, we have designed a 300-μm-diameter integrated metalens whose f-number is 0.8 and the simulation was carried out. The introduction of EIT metasurface does not affect the focusing near the diffraction limit at the target wavelength, and greatly reduces the influence of stray light caused by non-target wavelength incident light. This bandpass filter integrated metalens design method may have a great potential in the field of LWIR compact optical systems