Nanoporous aerogel fibers enjoy the luxury of being one of the most attractive nanomaterials. However, the representative fabrication pathways have faced up with low production rates due to significant speed mismatch between slow sol-gel transition and as fast as possible spinning in the same period. Herein, a novel gas-blows-liquid spinning (GS) strategy with a spinning speed of 300-700 m s is developed to get the high-speed and high-efficiency production of aerogel fibers/fabrics.
View Article and Find Full Text PDFMicrofluidic deprotonation approach is proposed to realize continuous, scalable, efficient, and uniform production of aramid nanofibers (ANFs) by virtue of large specific surface area, high mixing efficiency, strong heat transfer capacity, narrow residence time distribution, mild laminar-flow process, and amplification-free effect of the microchannel reactor. By means of monitoring capabilities endowed by the high transparency of the microchannel, the kinetic exfoliation process of original aramid particles is in situ observed and the corresponding exfoliation mechanism is established quantificationally. The deprotonated time can be reduced from the traditional several days to 7 min for the final colloidal dispersion due to the synergistic effect between enhanced local shearing/mixing and the rotational motion of aramid particles in microchannel revealed by numerical simulations.
View Article and Find Full Text PDFAerogel fibers, combining the nanoporous characteristics of aerogels with the slenderness of fibers, have emerged as a rising star in nanoscale materials science. However, endowing nanoporous aerogel fibers with good strength and high toughness remains elusive due to their high porosity and fragile mechanics. To address this challenge, this paper reports supertough aerogel fibers (SAFs) initially started from ionic-liquid-dissociated cellulose via wet-spinning and supercritical drying in sequence.
View Article and Find Full Text PDFThe pursuit of efficient CO capture materials remains an unmet challenge. Especially, meeting both high sorption capacity and fast uptake kinetics is an ongoing effort in the development of CO sorbents. Here, a strategy to exploit liquid-in-aerogel porous composites (LIAPCs) that allow for highly effective CO capture and selective CO /N separation, is reported.
View Article and Find Full Text PDFAerogel fibers garner tremendous scientific interest due to their unique properties such as ultrahigh porosity, large specific surface area, and ultralow thermal conductivity, enabling diverse potential applications in textile, environment, energy conversion and storage, and high-tech areas. Here, the fabrication methodologies to construct the aerogel fibers starting from nanoscale building blocks are overviewed, and the spinning thermodynamics and spinning kinetics associated with each technology are revealed. The huge pool of material choices that can be assembled into aerogel fibers is discussed.
View Article and Find Full Text PDFAerogel fibers, the simultaneous embodiment of aerogel porous network and fiber slender geometry, have shown critical advantages over natural and synthetic fibers in thermal insulation. However, how to control the building block orientation degree of the resulting aerogel fibers during the dynamic sol-gel transition process to expand their functions for emerging applications is a great challenge. Herein, nanoscale Kevlar liquid crystal (NKLC) aerogel fibers with different building block orientation degrees have been fabricated from Kevlar nanofibers liquid crystal spinning, dynamic sol-gel transition, freeze-drying, and cold plasma hydrophobilization in sequence.
View Article and Find Full Text PDFSmart and functional fibers have demonstrated great potentials in a wide range of applications including wearable devices and other high-tech fields, but design and fabrication of smart fibers with manageable structures as well as versatile functions are still a great challenge. Herein, an ingenious bending-stiffness-directed strategy is developed to fabricate smart phase-change fibers with different bending stiffnesses for diverse applications. Specifically, the hydrophobic Kevlar aerogel-confined paraffin wax fibers (PW@H-KAF) are fabricated by employing hydrophobic Kevlar aerogel fibers (H-KAFs) as the porous host and paraffin as the functional guest, where the H-KAF is obtained by applying a two-step process to functionalize Kevlar nanofibers (KNFs) with a special coagulation bath containing a mixture of ethanol and -bromobutane.
View Article and Find Full Text PDFAerogel fibers with ultrahigh porosity, large specific surface area, and ultralow density have shown increasing interest due to being considered as the next generation thermal insulation fibers. However, it is still a great challenge to fabricate arbitrary aerogel fibers via the traditional wet-spinning approach due to the obvious conflict between the static sol-gel transition of the aerogel bulks and the dynamic wet-spinning process of aerogel fibers. Herein, a sol-gel confined transition (SGCT) strategy was developed for fabricating various mesoporous aerogel fibers, in which the aerogel precursor solution was first driven by the surface tension into the capillary tubes, then the gel fibers were easily formed in the confined space after static sol-gel process, and finally the mesoporous aerogel fibers were obtained via the supercritical CO drying process.
View Article and Find Full Text PDFAerogel fibers, the simultaneous embodiment of aerogel 3D network and fibrous geometry, have shown great advantages over natural and synthetic fibers in thermal insulation. However, as a fast gelation to ensure aerogel fiber spinning generally induces rapid local clustering of precursor particles (, phase separation) and unavoidably results in nontransparency and nonuniformity in the gel state, a severe challenge remains in remedying the spinning to make transparent aerogel fibers come true. Herein, we report a reaction spinning toward highly porous silica aerogel fibers, where the Brownian motion (, diffusion) of colloidal particles is hampered during spinning to allow the maintaining of the fiber shape, while a rapid gelation reaction is activated by concentrated ammonia to solidify the fiber.
View Article and Find Full Text PDFAerogel with low density, high porosity, and large surface area is a promising structure for the next generation of high-performance thermal insulation fibers and textiles. However, aerogel fibers suffer from weak mechanical properties or complex fabricating processes. Herein, a facile wet-spinning approach for fabricating nanofibrous Kevlar (KNF) aerogel threads ( i.
View Article and Find Full Text PDFInfrared (IR) stealth is essential not only in high technology and modern military but also in fundamental material science. However, effectively hiding targets and rendering them invisible to thermal infrared detectors have been great challenges in past decades. Herein, flexible, foldable, and robust Kevlar nanofiber aerogel (KNA) films with high porosity and specific surface area were fabricated first.
View Article and Find Full Text PDFZhongguo Zhong Xi Yi Jie He Za Zhi
February 2013
Objective: To observe the therapeutic effects of beta-elemene combined DC/Dribble vaccine in treating mice with hepatic cancer, thus exploring their anti-tumor mechanisms.
Methods: Dentritic cells were derived from Balb/c mice's spleen and their phenotypes were identified. Using hepatic cancer cell line BNL1MEA.
Spectrochim Acta A Mol Biomol Spectrosc
November 2012
In this work, 4-(2-fluorobenzylideneamino)antipyrine (FBIAAP) was synthesized and characterized by elemental analysis, XRD, FT-IR, FT-Raman and UV-Vis techniques as well as density functional calculations. The studied molecule adopts a trans configuration about the imine CN bond, and adjacent molecules are linked through two kinds of weak hydrogen bonds to form supramolecular layered structures along the ab plane. Vibrational spectral analyses show that the benzene moiety directly attached to the central pyrazoline shows good vibrational isolation from the other moiety of pyrazole-imino-benzene presenting good vibrational resonances.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
October 2012
Recently, the study of imine-bridged organics is interested in proton-transfer and photo-responsive material fields. Herein, we make a investigation on the structural, thermodynamic and nonlinear optical properties of (E)-2-((2-hydroxyphenyl)iminiomethyl)phenolate (HPIMP). The structural varieties of the studied compound are characterized by the X-ray single crystal diffraction and vibrational spectral techniques, as well as the vibrational spectral bands are precisely ascribed to the studied structure with the aid of DFT theoretical calculations.
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