Three reusable and durable superhydrophobic nanofibrous filters were prepared by dip coating the nanofibrous fabric in the three different dispersed solutions of the newly modified nanoparticles (ZnO‐NSPO, AlOO‐NSPO, and titanium dioxide [TiO2]‐NSPO). The contact angle results proved that the TiO2‐NSPO coated nanofibrous polyacrylonitrile (PAN) filter was hydrophobic with the water contact angle (WCA) of 141° while the ZnO‐NSPO and AlOO‐NSPO coated nanofibrous PAN filters were superhydrophobic with the WCA of 168° and 152°, respectively. The as‐prepared filters can be utilized as an effective martial for oil‐water separation with separation efficiency of over 98%. 相似文献
A novel bi‐functional Janus cotton fabric is used to separate oil from oil‐in‐water emulsions. This fabric is superhydrophobic on one surface and polyamine‐bearing on the other. When used as a filter, the polyamine‐bearing side causes the micrometer‐sized oil droplets to coalesce. The coalesced oil then fills fabric pores on the superhydrophobic side and selectively permeates it. Oil separation using this method is rapid and the separated oil is pure. Furthermore, the content of the model oil hexadecane (HD) in water after a separation can be reduced to less than 0.03±0.03 vol %. These features demonstrate the practical potential of this technology. 相似文献
A graft-polymerization process with atomized lauryl methacrylate as monomer is used to fabricate fluorine-less and asymmetrically superhydrophobic cotton fabrics. The polymers synthesized in the process can form nanoscale hierarchical structures on the cotton surface, and the surface morphology can be controlled by choosing a suitable solvent or by varying the feeding quantity of the monomer mist stream. After applying the surface modification to cotton fabrics, an asymmetrically superhydrophobic surface is achieved without any additional nanosized particles, and the solvent damages on the cotton fabrics are controllable at a very low level. Surface characterization reveals that the modified side of the cotton fabric has laundering-durable and mechanically stable superhydrophobicity with a water contact angle of more than 150°, whereas the opposite inherits the hydrophilic property of pristine cotton fabric. The modified cotton fabrics are found to have medium-level water-absorbing ability between pristine cotton and PET fabrics, as well as good vapor transmissibility similar to pristine cotton fabric. These properties are of great significance in textile and medical applications. 相似文献
Electrospun nanofiber mats are inherently weak, and hence they are often deposited on mechanically-strong substrates such
as porous woven fabrics that can provide good structural support without altering the nanofiber characteristics. One major
challenge of this approach is to ensure good adhesion of nanofiber mats onto the substrates and to achieve satisfactory durability
of nanofiber mats against flexion and abrasion during practical use. In this work, Nylon 6 nanofibers were deposited on plasma-pretreated
woven fabric substrates through a new plasma-electrospinning hybrid process with the objective of improving adhesion between
nanofibers and fabric substrates. The as-prepared Nylon 6 nanofiber-deposited woven fabrics were evaluated for adhesion strength
and durability of nanofiber mats by carrying out peel strength and flex resistance tests. The test results showed significant
improvement in the adhesion of nanofiber mats on woven fabric substrates. The nanofiber-deposited woven fabrics also exhibited
good resistance to damage under repetitive flexion. X-Ray photoelectron spectroscopy and water contact angle analyses were
conducted to study the plasma effect on the nanofibers and substrate fabric, and the results suggested that both the plasma
pretreatment and plasma-electrospinning hybrid process introduced radicals, increased oxygen contents, and led to the formation
of active chemical sites on the nanofiber and substrate surfaces. These active sites helped in creating crosslinking bonds
between substrate fabric and electrospun nanofibers, which in turn increased the adhesion properties. The work demonstrates
that the plasma-electrospinning hybrid process of nanofiber mats is a promising method to prepare durable functional materials. 相似文献
Novel electrospun polyacrylonitrile (PAN) nanofibrous membranes were prepared by using heat-press lamination under various conditions. The air permeability and the burst-pressure tests were run to select the membranes for point-of-use air and water cleaning. Membrane characterization was performed by using scanning electron microscopy, contact angle, and average pore size measurements. Selected membranes were used for both air dust filtration and cross-flow water filtration tests. Air dust filter results indicated that electrospun PAN nanofibrous membranes showed very high air-dust filtration efficiency of more than 99.99 % in between PM0.3 and PM2.5, whereas cross-flow filtration test showed very high water permeability over 600 L/(m2hbar) after 6 h of operation. Combining their excellent efficiency and water permeability, these membranes offer an ideal solution to filter both air and water pollutants. 相似文献
Inspired by the surface structure of lotus leaves, different types of superhydrophobic cellulosic materials with contact angle (CA) of higher than 150° are currently provided. However, fabrication of these surfaces in a facile one-step coating process is one of the challenging issues. This paper describes a facile method to sonochemically synthesize superhydrophobic organic–inorganic hybrid coatings on cotton fabric by an alkaline-catalyzed co-hydrolysis and co-condensation of tetraethylorthosilicate and alkyltrialkoxysilanes. The influence of alkyl chain length (methyl, octyl, hexadecyl) of silane and reaction time was investigated. Surface structure of the fabrics was investigated by SEM, EDS, FTIR spectroscopies, and reflectance spectrophotometry. Wettability properties were studied by measuring water CA, shedding angle (SHA) and resistance to wetting by a series of ethanol–water mixtures of different surface tensions. The results showed that the treated fabrics were coated with a homogeneous thin nano-scaled coating of hybrid silica nano-particles. The fabrics demonstrated CA of higher than 150°, SHA in the range of 6–24° and different stickiness to water droplets. The fabrics treated by silanes with longer alkyl chain length and at higher reaction time revealed better water repellency. The coatings were nearly transparent, could not affect the color of the fabrics and had high stability against repeated washing. In addition, mechanical properties of the fabrics were not substantially affected. 相似文献
Summary: Hydrophilic acrylic nanofibers were prepared from alkaline hydrolysis of hydrophobic polyacrylonitrile (PAN) nanofibers. Water contact angle, pore volume, and liquid retention capacity of PAN nanofibrous membranes were measured to determine their dependence on hydrolysis parameters such as base concentration, temperature, and time. Vertical water retention capacity of hydrolyzed PAN nanofibrous membrane could reach as large as 200 times of that of original membrane.
Fiber twinning in post‐hydrolyzed PAN nanofibrous membrane. 相似文献
The poor mechanical stability of superhydrophobic fabrics severely hindered their use in practical applications. Herein, to address this problem, we fabricated a superhydrophobic fabric with both mechanical stability and easy-repairability by a simple method. The mechanical durability of the obtained superhydrophobic fabric was evaluated by finger touching and abrasion with sandpaper. The results show that rough surface textures of the fabric were retained, and the fabric surface still exhibited superhydrophobicity after tests. More importantly, when the fabric lost its superhydrophobicity after a long-time abrasion, it can be easily rendered with superhydrophobicity once more by a regeneration process. 相似文献
The superhydrophobic cotton fabrics were prepared by combining the coating of titanium dioxide (TiO2) with the subsequent dodecafluoroheptyl-propyl-trimethoxysilane (DFTMS) modification. Scanning electron microscopy (SEM)
and X-ray diffraction (XRD) measurements revealed that the nanosized TiO2 sphere consisted of granular rutile. The TiO2 layer coated on the cotton altered both the surface roughness for enhancing the hydrophobicity and UV-shielding property.
The cotton fabric samples showed excellent water repellency with a water contact angle as high as 162°. The UV-shielding was
characterized by UV-vis spectrophotometry, and the results indicated that the fabrics could dramatically reduce the UV radiation.
The photocatalytic progress showed that organic stains were successfully degraded by exposure of the stained fabric to UV
radiation. Such multifunctional cotton fabrics may have potentials for commercial applications. 相似文献
A cotton fabric was coated with a polymer that contains both poly(dimethyl siloxane) (PDMS) and poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA). When the repeat unit number of PDMS is about three‐fold that of PDMAEMA and the fabric is exposed to air, the fabric is superhydrophobic because PDMS in the coating covers the PDMAEMA chains. Upon contact with an oil‐in‐water emulsion, the water‐soluble PDMAEMA rises to the top and the side in contact with the emulsion becomes hydrophilic. The emerged PDMAEMA chains then cause the emulsion droplets to coagulate, and the aggregated oil fills the pores on the superhydrophobic side of the fabric. The oil‐impregnated side remains hydrophobic even upon prolonged contact with water. Thus, a Janus fabric is elegantly generated in situ and sustained. This easy‐to‐prepare Janus fabric rapidly and efficiently separates oil from emulsions and may find practical applications. 相似文献
In the present study, a novel and simple method of obtaining superhydrophobic surface through the migration of organic siloxane
segments in the acrylate side chains to the outmost layer and forming the nano-protuberance on the micro-roughness wool fabrics
was described. The chemical compositions and morphologies of the untreated/treated fabrics were characterized by the scanning
electron microscopy and X-ray photoelectric energy spectroscopy. Meanwhile, the surface hydrophobicity was evaluated by the
static contact angle measurement. The scanning electron microscopy photographs showed that the fiber surfaces of the treated
fabrics were obviously granulated, and a wax film covered on the fibers could be observed. X-ray photoelectron spectroscopy
analyses and static contact angle measurement further testified that the component of the wax was almost siloxane and that
the surfaces of the treated fabrics had superhydrophobic property. The above results indicated that this method could be extended
to prepare superhydrophobic surfaces by migrating the low-surface-energy matter and fabricating the nanoscale roughness on
the micro-roughness material surfaces. 相似文献
Water flux and hydrophobic durability play important roles in membrane distillation(MD) applications. Compared with the method of adsorbing nanoparticles by electrostatic adsorption, the surface roughness constructed by chemical bonding is more conducive to the performance of membrane. This paper reports a facile approach to fabricating superhydrophobic fluoroalkyl silane/polydimethylsiloxane@FeOOH@stabilized polyacrylonitrile(FAS/PDMS@FeOOH@SPAN) nanofibrous membrane (NFM) with outstanding hierarchical structures, aiming to achieve efficient and stable performance in MD. Electrospun polyacrylonitrile(PAN) membrane after peroxidation was chosen as the base membrane, followed by in-situ synthesis of iron oxyhydroxide and liquid-phase silanization. We tested the characteristics of FAS/PDMS@FeOOH@SPAN NFM in each preparation stage and its performance in direct contact membrane distillation(DCMD). The chemical bond between iron oxyhydroxide and the membrane is stronger, making the rough structure steady and dense. The FAS/PDMS@FeOOH@SPAN NFM exhibited a water contact angle of 155.4° and excellent hydrophobicity towards different pollutants. Besides, it showed satisfied properties with a water flux of 24.7 L·m-2·h-1, a high salts rejection of ca. 100% and an extended-term stability in DCMD using hypersaline water(10%, mass ratio). It is believed that this novel study proposes a universal and efficient method to fabricate a superhydrophobic surface and has great potential for high-salinity wastewater treatment in MD. 相似文献
This article presents the findings concerning the preparation and properties of cotton woven fabrics with a conductive network made of multiwall carbon nanotubes deposited on the fiber surface by the padding method. The next stage of treatment consisted of imparting superhydrophobic properties to the fabrics in solution with methyltrichlorosilane (MTCS) in a waterless medium. The tests performed show that the state of surface and water content in cotton fibers exerts a significant influence on the hydrophobic properties of the analyzed samples. In order to explain the differences in hydrophobic properties, the morphology of the cotton fabric surface was examined using samples with various water contents. The formation mechanism of MTCS coatings on cotton fabric has been proposed. 相似文献
Durable superhydrophobic surface on cotton fabrics has been successfully prepared by sol–gel method. Cellulose fabric was
first coated with silica sol prepared with water glass and citric acid as the acidic catalyst. The silica coated fabric was
then padded with hydrolyzed hexadecyltrimethoxysilane afterwards obtaining low surface energy. Water contact angle and hydrostatic
pressure were used to characterize superhydrophobicity and washing durability. Scanning electron microscopy was used to characterize
the surface morphology changes after certain washing times. All results showed good durable hydrophobicity on cellulose fabrics.
In addition, the influence of citric acid and sodium hypophosphite (NaH2PO2) on the durability of hydrophobicity was also investigated. The durability of treated cotton improved with the increase of
concentration of citric acid in the presence of NaH2PO2. It could be concluded that citric acid acted as multi-functional heterogeneous grafting chemicals to improve washing durability
of hydrophobicity by forming the ester bonds between cotton fabric and silica sol and improved the durability of hydrophobicity. 相似文献
We report a simple and versatile approach to creating a highly transparent superhydrophobic surface with dual-scale roughness on the nanoscale. 3-Aminopropyltrimethoxysilane (APTS)-functionalized silica nanoparticles of two different sizes (100 and 20 nm) were sequentially dip coated onto different substrates, followed by thermal annealing. After hydrophobilization of the nanoparticle film with (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane for 30 min or longer, the surface became superhydrophobic with an advancing water contact angle of greater than 160° and a water droplet (10 μL) roll-off angle of less than 5°. The order of nanoparticles dip coated onto the silicon wafer (i.e., 100 nm first and 20 nm second or vice versa) did not seem to have a significant effect on the resulting apparent water contact angle. In contrast, when the substrate was dip coated with monoscale nanoparticles (20, 50, and 100 nm), a highly hydrophobic surface (with an advancing water contact angle of up to 143°) was obtained, and the degree of hydrophobicity was found to be dependent on the particle size and concentration of the dip-coating solution. UV-vis spectra showed nearly 100% transmission in the visible region from the glass coated with dual-scale nanoparticles, similar to the bare one. The coating strategy was versatile, and superhydrophobicity was obtained on various substrates, including Si, glass, epoxy resin, and fabrics. Thermal annealing enhanced the stability of the nanoparticle coating, and superhydrophobicity was maintained against prolonged exposure to UV light under ambient conditions. 相似文献
The application of carbon nanotube or nanorod/polyacrylonitrile (PAN) composite electrospun nanofibrous stationary phase for ultrathin layer chromatography (UTLC) is described herein. Multi-walled carbon nanotubes (MWCNTs) and edge-plane carbon (EPC) nanorods were prepared and electrospun with the PAN polymer solution to form composite nanofibers for use as a UTLC stationary phase. The analysis of laser dyes demonstrated the feasibility of utilizing carbon nanoparticle-filled electrospun nanofibers as a UTLC stationary phase. The contribution of MWCNT or EPC in changing selectivity of the stationary phase was studied by comparing the chromatographic behavior among MWCNT–PAN plates, EPC–PAN plates and pure PAN plates. Carbon nanoparticles in the stationary phase were able to establish strong π–π interactions with aromatic analytes. The separation of five polycyclic aromatic hydrocarbons (PAHs) demonstrated enhanced chromatographic performance of MWCNT-filled stationary phase by displaying substantially improved resolution and separation efficiency. Band broadening of the spots for MWCNT or EPC-filled UTLC stationary phases was also investigated and compared with that for pure PAN stationary phases. A 50% improvement in band dispersion was noted using the MWCNT based composite nanofibrous UTLC plates. 相似文献
The acoustical damping property of electrospun polyacrylonitrile(PAN) nanofibrous membranes with different thicknesses and porosities was investigated.The sound absorption coefficients were measured using the impedance tube instrument based on ISO 10534-2:1998(E).Results indicate that the first resonance absorption frequency of nanofibrous membranes shifts to the lower frequency with the increase of the back cavity or the thickness of membranes.Moreover,the sound absorption performance of the perforated panel can be greatly improved by combination with a thin layer of PAN nanofibrous membrane.Traditional acoustical damping materials(foam,fiber) coated with nanofibrous membranes have better acoustical performance in the low and medium frequency range than that of acoustical materials alone.All of the results demonstrate the PAN nanofibrous membrane is a suitable candidate for noise reduction. 相似文献
An industrial waterproof reagent [(potassium methyl siliconate) (PMS)] was used for fabricating a superhydrophobic surface on a cellulose-based material (cotton fabric or paper) through a solution-immersion method. This method involves a hydrogen bond assembly and a polycondensation process. The silanol, which was formed by a reaction of PMS aqueous solution with CO 2, was assembled on the cellulose molecule surface via hydrogen bond interactions. The polymethylsilsesquioxane coatings were prepared by a polycondensation reaction of the hydroxyl between cellulose and silanol. The superhydrophobic cellulose materials were characterized by FTIR spectroscopy, thermogravimetry, and surface analysis (XPS, FESEM, AFM, and contact angle measurements). Analytical characterization revealed that nanoscale roughness protuberances uniformly covered the surface, thus transforming the cellulose from superhydrophilic to superhydrophobic with a water contact angle of 157 degrees . The superhydrophobic coatings were satisfactory with regard to both chemical and mechanical durability, and because of the transparency of the coatings the native cotton fabric displayed no changes with regard to either morphology or color. The easy availability of the materials and simplicity of this method render it convenient for mass production. 相似文献