ABSTRACT
With the development of industry and global warming, passive radiative cooling textiles have recently drawn great interest owing to saving energy consumption and preventing heat-related illnesses. Nevertheless, existing cooling textiles often lack efficient sweat management capacity and wearable comfort under many practical conditions. Herein, a hierarchical cooling metafabric that integrates passive radiation, thermal conduction, sweat evaporation, and excellent wearable comfort is reported through an electrospinning strategy. The metafabric presents excellent solar reflectivity (99.7%, 0.3-2.5 µm) and selective infrared radiation (92.4%, 8-13 µm), given that the unique optical nature of materials and wettability gradient/micro-nano hierarchical structure design. The strong moisture-wicking effect (water vapor transmission (WVT) of 2985 g m-2 d-1 and directional water transport index (R) of 1029.8%) and high heat-conduction capacity can synergistically enhance the radiative cooling efficiency of the metafabric. The outdoor experiment reveals that the metafabric can obtain cooling temperatures of 13.8 °C and 19.3 °C in the dry and sweating state, respectively. Meanwhile, the metafabric saves ≈19.3% of annual energy consumption compared with the buildings with HAVC systems in Shanghai. The metafabric also demonstrates desirable breathability, mechanical strength, and washability. The cost-effective and high-performance metafabric may offer a novel avenue for developing next-generation personal cooling textiles.
ABSTRACT
In order to address the requirements for warmth and energy conservation in cold climates, the development of personal thermal management textiles that regulate local human thermal comfort has emerged as a promising solution in recent times. Nevertheless, existing warming textile strategies often rely on a singular energy source, exhibit inadequate air/moisture permeability, and lack adaptability to dynamic and intricate climate variations. Herein, a novel multienergy-coupled radiative warming Janus textile has been effectively designed and fabricated via screen printing and foam finishing. Taking advantage of the synergistic effects of directional water transport capability of polyester-covered cotton (with a directional water-transport index of R = 577.5%), high mid-infrared radiant reflection (at 60%), electrothermal conversion of copper coating (with a sheet resistance of 0.01 Ω sq-1), and strong solar absorption of the nanoporous structure TA@APTES@Fe(III)@CNT (TAFC) coating (at 98.5%), the Janus fabric exhibits exceptional performance in expelling out one-way sweat/moisture (R = 329.3%) and solar heating (86.9 °C)/Joule heating (226.4 °C at 3.0 V)/heat retention (2.4 °C higher than that of cotton fabric). Furthermore, the fabric is also provided with exceptional mechanical, washing, flame-retardant, and antibacterial performance. This research holds the potential to revolutionize the development and production of warming textiles by incorporating desirable sweat/moisture permeability and multienergy-coupled heating.
ABSTRACT
Homogeneously dispersed copper nanowire (CuNW) materials are the basis for practical applications in many types of electronic devices. At present, the dispersion of CuNWs in water is achieved through polymeric spatial site resistance effects primarily and the electrostatic dispersion mechanism in a few. However, the electrical conductivity of CuNWs could be weakened by the excessive addition of polymers; therefore, it is difficult to maintain a stable dispersion enduringly for surface charge modifiers. Based on the coagulation mechanism of colloids, a novel antisedimentation mechanism is refined by this work. Directed by this mechanism, a stable reciprocal-supporting antisedimentation conductive CuNW ink was achieved enduringly and a uniform conductive coating (1.81-5.65 Ω·sq-1) was successfully manufactured. The tannic acid-polyethylene imine (TA-PEI) could support copper nanowires to maintain a stable height of 61.4% after 15 days best, while CuNWs in other systems would settle completely in one day. Meanwhile, the TA-PEI composite cluster antisedimentation network not only provided massive spatial potential resistance for CuNWs but also modified the surface charge of CuNWs. CuNWs were dispersed stably in this phenol-amine@CuNW network. Furthermore, the CuNWs were crosslinked more tightly with each other relying on the vigorous adhesive properties of TA-PEI. With this antisedimentation mechanism and simple treatment process, CuNW ink will be utilized in more applications.
ABSTRACT
Multifunctional wearable heaters have attracted much attention owing to their efficient application in personal thermal management. Inspired by the polar bear's thermal management, a laminated fabric with enhanced photothermal conversion, mid-infrared reflection, thermal insulation, and electrical heating performance was developed in this work, which was made of CNT/cellulose aerogel layers, cotton fabrics, and copper nanowire (CuNW)-based conductive network (CNN) layers. The CNN layer made up of highly conductive CuNWs not only exhibits better conductivity to realize the Joule heating effect but also possesses a human mid-infrared reflection property. Moreover, the other side of the cotton fabric was laminated with CNT/cellulose aerogel, which enables the fabric to have a good photothermal conversion ability and thermal insulation performance. The temperature of the laminated fabric could reach to 70 °C within 80 s under 1.8 V; it requires more than 500 s to return to room temperature (28.7 °C). When the light intensity was adjusted to 1000 W/m2, the temperature of the laminated fabric was about 74.0 °C after lighting for 280 s. Our work provides a new approach to improving the performance and energy-saving of personal thermal management fabrics.
ABSTRACT
The composite material composed of zinc sulfide, copper sulfide and porous carbon is prepared in this study, exhibiting excellent performances in the field of supercapacitor electrode and photocatalysts. In the degradation process of organic pollutants, zinc sulfide/copper sulfide with heterostructure effectively reduce the recombination rate of photo-generated electron-hole pairs. And the porous carbon substrate can not only accelerate the separation of photo-carriers but also provide numerous active sites. Furthermore, the sample can be easily separated after decomposing the organic pollutants. As a supercapacitor electrode, the combination of zinc sulfide/copper sulfide with large pseudo-capacitance and porous carbon material with excellent double-layercapacitance results in superior electrochemical performances. The composite electrode shows a high specific capacitance of 1925 mF cm-2/0.53 mAh cm-2 at 4 mA cm-2. And the symmetric flexible supercapacitor based on the composite electrode achieves an outstanding energy density (0.39 Wh cm-2 at the power density of 4.32 W cm-2). Therefore, the zinc sulfide/copper sulfide/porous carbonized cotton nanocomposites (pCZCS) prepared herein exhibit dual functions of photocatalysts with high efficiency as well as energy storage materials with high energy density, which is interesting and important for expanding the practical applications in cross fields.
ABSTRACT
A novel pH-responsive Ag@polyacryloyl hydrazide (Ag@PAH) nanoparticle for the first time as a surface-enhanced Raman scattering (SERS) substrate was prepared without reducing agent and end-capping reagent. Ag@PAH nanoparticles exhibited an excellent tunable detecting performance in the range from pH = 4 to pH = 9. This is explained that the swelling-shrinking behavior of responsive PAH can control the distance between Ag NPs and the target molecules under external pH stimuli, resulting in the tunable LSPR and further controlled SERS. Furthermore, Ag@PAH nanoparticles possessed an ultra-sensitive detecting ability and the detection limit of Rhodamine 6G reduced to 10-12 M. These advantages qualified Ag@PAH NP as a promising smart SERS substrate in the field of trace analysis and sensors.
ABSTRACT
A strategy for significantly enhancing fluorescence is developed based on the coupling of optical properties of colloidal photonic crystals (CPCs) with responsive microgel. In this paper, thermoresponsive microgel PNIPAM was employed for the fabrication of core-shell structure. The core-shell PS@PNIPAM nanoparticles (NPs) are then assembled to CPCs by a vertical deposition method. Subsequently, the novel functional material (RhB/CPCs) can be prepared by depositing fluorescent dye molecules (RhB) on the top of PS@PNIPAM CPCs. We obtained an increase in the fluorescent intensity up to 15-fold and 22-fold compared with RhB on the glass slid and the uneven film. Due to the unique responsive shrinking properties of PNIPAM shell, the amplifying fluorescence behavior of CPCs can be well tuned by varying the temperature. In contrast to RhB on the glass slid, a 15-fold and 12-fold fluorescence enhancement can be observed when the temperature of RhB/CPCs was 20 °C and 50 °C, respectively. The mechanism on enhancement fluorescence of tunable CPCs can be achieved by measurements of thermoresponsive properties. The results indicate that the responsive fluorescence-amplifying method based on CPCs made with responsive core-shell NPs has a potential application for the development of efficient fluorescence sensors.
ABSTRACT
The proposed approach for fabricating ultralight self-sustained electrodes facilitates the structural integration of highly flexible carbon nanofibers, amino-modified multiwalled carbon nanotubes (AM-MWNT), and MnO2 nanoflakes for potential use in wearable supercapacitors. Because of the higher orientation of AM-MWNT and the sublimation of terephthalic acid (PTA) in the carbonization process, freestanding electrodes could be realized with high porosity and flexibility and could possess remarkable electrochemical properties without using polymer substrates. Wearable symmetric solid-state supercapacitors were further assembled using a LiCl/PVA gel electrolyte, which exhibit a maximum energy density of 44.57 Wh/kg (at a power density of 337.1 W/kg) and a power density of 13330 W/kg (at an energy density of 19.64 Wh/kg) with a working voltage as high as 1.8 V. Due to the combination of several favorable traits such as flexibility, high energy density, and excellent electrochemical cyclability, the presently developed wearable supercapacitors with wide potential windows are expected to be useful for new kinds of portable electric devices.
ABSTRACT
A facile and highly efficient method for the fabrication of free-standing three-dimensional (3D) composites with different morphologies was designed by the combination of the electrospinning method and hydrothermal reaction. The controlled hierarchical nanoarrays showed excellent electrochemical performance for their potential use as supercapacitor electrodes.
Subject(s)
Electric Capacitance , Microscopy, Electron, ScanningABSTRACT
A series of regiospecific chlorinated fluoresceins have been synthesized by the reaction of the regiospecific chlorinated resorcinols with chlorinated phthalic anhydride. The regioisomers were successfully separated by chromatography. The photophysical properties of the obtained chlorinated fluoresceins were examined and found their absorption and emission maxima at long wavelength with high fluorescence quantum yield. Especially, pH-dependent properties of chlorinated fluoresceins have been studied in detail. These compounds show strongly pH-sensitive range of 3.5-7.0, and have lower pK (a) values than fluorescein. Furthermore, their fluorescent intensity could reach the maximum in the physiological environment of pH range 6.8-7.4. Due to higher fluorescence quantum yield and lower pK (a) values, chlorinated fluoresceins will be expected to be used as excellent pH fluorescent probes for pH measurement of the acidic cell.
Subject(s)
Fluoresceins/chemistry , Fluorescent Dyes/chemistry , Hydrocarbons, Chlorinated/chemistry , Algorithms , Fluoresceins/chemical synthesis , Fluorescent Dyes/chemical synthesis , Hydrocarbons, Chlorinated/chemical synthesis , Hydrogen-Ion Concentration , Molecular Structure , Spectrometry, Fluorescence , Spectrophotometry, UltravioletABSTRACT
In the title compound, C(21)H(24)O(2), rings B, C and D adopt half-chair, distorted half-chair and envelope conformations, respectively. In the crystal structure, there is an inter-molecular O-Hâ¯O hydrogen bond. The mol-ecules are arranged in a head-to-tail fashion, with the meth-oxy and hydr-oxy groups forming a two-dimensional hydrogen-bond network.
ABSTRACT
A new mixture of 4- and 7-chlorofluorescein were synthesized by condensation of resorcinol with 3-chlorophthalic anhydride in the presence of methanesulfonic acid or zinc chloride. These regioisomers were successfully separated by chromatography. The photophysical properties were examined and their absorption and emission maxima at long wavelength, high fluorescence quantum yield, and narrow emission bandwidth were found, highly favorable for detecting multiple target substances in the same sample. Furthermore, 4(7)-chlorofluorescein was found to be strongly pH-dependent between 4.0 and 8.0, and could be used as pH-sensitive fluorescent probe to measure intracellular pH.
Subject(s)
Fluoresceins/chemistry , Fluorescent Dyes/chemistry , Fluoresceins/chemical synthesis , Fluorescent Dyes/chemical synthesis , Hydrogen-Ion ConcentrationABSTRACT
In air oxidation of penicillin G p-methoxybenzyl ester (PGPMB) to its sulfoxides (PGPMBO), sol-gel technique was employed to encapsulate the catalyst Co (acac)3, by which the reaction was run under heterogeneous conditions. A reversed-phase high performance liquid chromatographic method was established for the determination of the conversion of this reaction. The analysis of PGPMBO was carried out on a C18 column (4.6 mm i.d. x 150 mm, 10 microm) with the mobile phase of methanol-water (85:15, V/V), at a flow rate of 1 mL min(-1) and with detection wavelength of 270 nm. The linearity of the calibration curve of PGPMBO was obtained over the range of 0.05 g x L(-1) - 0.40 g x L(-1) with a relative coefficient of 0.999 2. The highest conversion was 98.8%. The method can be applied to determine this conversion promptly in the reaction system.
