Zhang Jiawei,Zhang Guoping,Gao Yongju,Sun Rong,Wong C. P.
A novel bridged organosilane precursor with star-shaped construction, [hexfluoropropane-2,2-diyl)dibenzyl-bridged organosilane (HFPDBO)], is prepared by facile organic synthesis method. The resultant HFPDBO precursor is mixed with porogen and acid catalyst to prepare periodic mesoporous organosilica (PMO) thin film via evaporation-induced self-assembly after spin-coating procedure. All the as-prepared HFPDB-based PMO thin film has been characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectrum, scanning electron microscopy,
transmission electron microscope, and small-angle X-ray diffraction, respectively. Thereinto, the HFPDB-based PMO thin film with weight ratio of porogen to precursor (0.75:1) possesses excellent dielectric property (1.58@1 MHz of dielectric constants), high mechanical property (5.54 ± 0.11 GPa of Young’s modulus) and hydrophobic property (90.1° of water contact angle) simultaneously. These low dielectric constant, high mechanical strength, and the hydrophobicity suggest potential application of the HFPDB-based PMO thin films as low-k materials in microelectronics.
In this paper, new two-component organogels via hexafluoropropane amino derivative and acids with different molecular skeletons were designed and prepared. Their gelation behaviors in some solvents were tested and investigated as new two-component organic gelators. The obtained experimental data demonstrated that the solvents and molecular skeletons played a crucial role in regulating the gelation behaviors and fabrication of nanostructures. Suitable solvents seemed favorable for the formation of supramolecular gels due to cooperation of multi-intermolecular weak forces. Rational self-assembly modes in organogels were proposed and discussed. The present research work may demonstrate new insight to design new two-component soft materials with special nanostructures.
Cui-Wei Wang,Shi-Ping Yang,He Hu,Jing Du,Feng-Hua Li
The present study aimed to prepare perfluoropropane (C3F8)-filled poly(lactic-co-glycolic acid) (PLGA) nanoparticles and investigate the feasibility of using PLGA nanoparticles as an ultrasound contrast agent. The PLGA nanoscale ultrasound contrast agent was prepared using a modified double-emulsion solvent evaporation method. Camphor in the form of a sublimable porogen was added to render the nanoparticles hollow and enable C3F8 gas introduction. Various physicochemical properties of PLGA nanoparticles, including morphology, size and dispersion, were analyzed by electron microscopy and dynamic laser scattering. In vitro ultrasound imaging of C3F8-filled PLGA nanoparticles was also investigated under various imaging conditions. Further in vivo ultrasound imaging was conducted on male rats following intratesticular injection of PLGA nanoparticles. C3F8-filled PLGA nanoparticles with a mean diameter of 152.0±58.08 nm were obtained. Electron microscopy revealed spherical-shaped nanoparticles with smooth surfaces, a capsular morphology and a large hollow within. In vitro ultrasound imaging of hollow PLGA nanoparticles indicated marked signal enhancement. Local intensity of the acoustical signal continued to increase during PLGA-nanoparticle injection into the testicle and the ability of hollow PLGA nanoparticles to enhance ultrasound imaging in vivo was demonstrated. The enhancement image of testicular tissue following injection with C3F8-filled PLGA nanoparticles was sustained for a minimum of five minutes. In conclusion, the hollow C3F8-filled PLGA nanoparticles were demonstrated to have potential for applications as a novel ultrasound contrast agent.
Electronic crosstalk, signal propagation delay and loss on the redistribution layers (RDLs) have been increasingly serious along with the rapid development of wafer-level packing (WLP). Polyimide films with low dielectric permittivity (D k ) and low dielectric loss (D f ) at high frequency are in demand imminently as interlayer materials. In this work, a novel kind of intrinsic silane-containing polyimide was designed and prepared by the reactions of 1,3-Bis(3-aminopropyl)tetramethyldisiloxane (APDS) and 4,4′-Oxydianiline (ODA) with 2,2-Bis(3,4-anhydrodicarboxyphenyl) hexafluoropropane (6FDA). The chemical structure of polyimide was studied by FT-IR spectrum and NMR and their dielectric properties and other performances were systematically analyzed. Results showed that the lowest D k and D f of polyimide (6FDA/APDS) was 2.66 and 6 × 10 −4 at 10 GHz. Furthermore, the dielectric permittivity and loss of silane-containing polyimide decreased with increasing the content of silane . The excellent dielectric properties were attributed to decreasing polarization and increasing the free volume of molecular chains when the silane was introduced into the molecular structure of polyimide. This work provided guidance for the intrinsic silane-containing polyimide with low dielectric properties.
危险品化学品经营许可证（带存储）