Three‐dimensional electrospun micropatterned cellulose acetate nanofiber surfaces with tunable wettability

Three‐dimensional polymer nanofibrous mats with tunable wettability have been fabricated using a single step non‐conductive template assisted electrospinning process. Cellulose acetate nanofibers are electrospun over a nylon mesh, which acts as the template. The as‐deposited fiber mat is removed from this template to produce a free standing three‐dimensional micropatterned nanofibrous mat. By simply varying the template mesh dimensions, the fraction of the air‐liquid interface can be changed which allows control of the wetting mechanics. It is shown that the water contact angle can be varied from about 30° for a planar network to about 140° for a patterned mat implying a complete transition from hydrophilic to hydrophobic behavior. Furthermore, upon stretching the fiber mat loses its pattern irreversibly and reducing the contact angle from 140° to 110° with increasing stretching. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44709.     

Silver Nanoparticles Loaded Thermoresponsive Hybrid Nanofibrous Hydrogel as a Recyclable Dip‐Catalyst with Temperature‐Tunable Catalytic Activity

Silver nanoparticles (AgNPs) loaded thermoresponsive nanofibrous hydrogel is fabricated by electrospinning the aqueous solution containing the metal nanoparticles and poly((N‐isopropylacrylamide)‐co‐(N‐hydroxymethylacrylamide)) copolymer, followed by heat treatment. To avoid negative effect of the stabilizer or the residual reductant on their performances, the AgNPs of less than 5 nm size are synthesized through reducing Ag⁺ ions in the spinning solution by UV irradiation. The prepared nanofibrous hydrogel with desirable stability in aqueous medium has significant thermoresponsive property, and can reach its swelling or deswelling equilibrium state within 15 s with the medium temperature changing between 25 and 50 °C alternately. The smart nanofibrous hydrogel as a dip‐catalyst has the catalysis for the reduction of 4‐nitrothiophenol to 4‐aminothiophenol by NaBH₄, and its catalytic activity can be rapidly tuned by temperature. Moreover, it can be facilely recycled from the reaction system at least four times, without any loss of its catalytic activity.     

Electrospun soy‐protein‐based nanofibrous membranes for effective antimicrobial air filtration

Soy proteins are gaining more and more attention because of its multifunction and biodegradability. Silver nanoparticles (AgNPs) are introduced into the nanofibers to prevent growth of microorganisms over the filter media. In the present study, the multifunctional and antimicrobial nanofibrous membranes were prepared by electrospinning the soy protein isolate (SPI)/polymide‐6 (PA6)‐silver nitrate system followed by ultraviolet reduction. The morphology of SPI/PA6 nanofibrous membranes was characterized by scanning electron microscopy. Antibacterial property of nanofibrous membranes were investigated against Escherichia coli and Bacillus subtilis. The optimized fiber membrane exhibited over 95% filtration efficiency of PM_0.3 (particulate matter size less than 0.3 μm). The successful synthesis of SPI/PA6‐AgNPs nanofibrous membranes would make it to be the potential candidate for novel antibacterial and high‐performance air filter. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45766.     

Effect of solvent quality and humidity on the porous formation and oil absorbency of SAN electrospun nanofibers

In this study, nanofibrous mat with high oil sorption capability was prepared via one‐step electrospinning process without any further post‐treatments. For this purpose, the fabrication of styrene/acrylonitrile copolymer nanofibers was carried out using various dimethylformamide (DMF)/tetrahydrofuran and DMF/ethanol (DMF/EtOH) binary mixture ratios in an electrospining atmosphere with various relative humidity (RH) levels. Scanning electron microscope micrographs showed that DMF/tetrahydrofuran and DMF/EtOH ratio and RH value could considerably affect the diameter, surface, and interior morphology of the resultant nanofibers. The nanofiber morphology was dependent upon the polymer/solvent(s)/water ternary phase diagram behavior. In overall, the partial hydrophilicity of styrene/acrylonitrile copolymer resulted in electrospun nanofibers with wrinkled surface. In addition, the incorporation of nonsolvent in the spinning solution and using high RH atmosphere forced the polymeric solution jet to intensively phase separate and, therefore, produce the nanofibers with highly interior porous structure during drying process. The maximal capacity and rate of oil sorption (170 g/g) was observed for the nanofibrous mat prepared using EtOH/DMF (2/3: vol/vol) and RH value of 60% showing the highest internal porosity. The results showed that the oil sorption capability and mechanical strength of the fibrous mat are strongly dependent on nanofibers diameter and porous structure, which can be controlled through adjusting the RH and spinning solvent quality. The electrospun mat with highest Young's modulus (7.68 MPa) was prepared using EtOH/DMF (2/3) binary mixture and RH value of 45%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45586.     

Electrospinning of solvent‐resistant nanofibers based on poly(acrylonitrile‐co‐glycidyl methacrylate)

This article reports on the preparation of novel solvent‐resistant nanofibers by electrospinning of poly(acrylonitrile‐co‐glycidyl methacrylate) (PANGMA) and subsequent chemical crosslinking. PANGMA nanofibers with diameters ranging from 200 to 600 nm were generated by electrospinning different solutions of PANGMA dissolved in N,N‐dimethylformamide. Different additives were added to reduce the fiber diameter and improve the morphology of the nanofibers. The as‐spun PANGMA nanofibers were crosslinked with 27 wt % aqueous ammonia solution at 50°C for 3 h to gain the solvent resistance. Swelling tests indicated that the crosslinked nanofibers swelled in several solvents but were not dissolved. The weight loss of all the crosslinked nanofibrous mats immersed in solvents for more than 72 h was very low. The characterization by electron microscopy revealed that the nanofibrous mats maintained their structure. This was also confirmed by the results of the pore size measurements. These novel nanofibers are considered to have a great potential as supports for the immobilization of homogeneous catalysts and enzymes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

High performance electrospun PVdF‐HFP/SiO2 nanocomposite membrane electrolyte for Li‐ion capacitors

Electrospun poly[(vinylidene fluoride)‐co ‐hexafluoropropylene]/silica (PVdF‐HFP/SiO₂) nanocomposite polymer membranes (esCPMs) were prepared by incorporating different weight percentages of SiO₂ nanoparticles onto electrospun PVdF‐HFP by electrospinning technique. The surface morphology of electrospun PVdF‐HFP nanocomposite membranes was characterized by scanning electron microscopy. The effect of SiO₂ nanoparticles incorporation onto electrospun PVdF‐HFP polymer membranes (esPMs) has been studied by XRD, DSC, TGA, and tensile analysis. The electrospun PVdF‐HFP/SiO₂ based nanocomposite membrane electrolytes (esCPMEs) were prepared by soaking the corresponding esCPMs into 1 M LiPF₆ in EC:DMC (1:1 vol/vol %). The ionic conductivity of the esCPMEs was studied by AC‐impedance studies and it was found that the incorporation of SiO₂ nanoparticles into PVdF‐HFP membrane has improved the ionic conductivity from 1.320 × 10^?3 S cm^?1 to 2.259 × 10^?3 S cm^?1. The electrochemical stability of the esCPME was studied by linear sweep voltammetry studies and it was found to be 2.87 V. Finally, a prototype LiCo_0.2Mn_1.8O₄//C Li‐ion capacitor (LIC) cell was fabricated with esCPME, which delivered a discharge capacitance of 128 F g^?1 at the current density of 1 A g^?1 and retained 86% of its discharge capacitance even after 10,000 cycles. These results demonstrated that the esCPMEs could be used as promising polymer membrane electrolyte for LICs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45177.     

Multilevel‐layer‐structured polyamide 6/poly(trimethylene terephthalate) nanofibrous membranes for low‐pressure air filtration

Multilevel‐layer‐structured polyamide 6 (PA6) and poly(trimethylene terephthalate) (PTT) nanofibrous membranes were fabricated by an electrospinning method. The morphology of the multileveled layers membranes were characterized by scanning electron microscopy. The tensile strength of the PA6–PTT membranes were controlled by the regulation of the layer structure. Additionally, the surface area of the multilevel‐layer‐structured membranes was also investigated with the nitrogen physisorption isotherms. Furthermore, the multilevel‐layered membranes, with a tensile strength of 9.8 MPa and a surface area of 5.1601 m²/g on 300‐nm dioctylphthalate (DOP) aerosol particles, showed a higher efficiency (95.825%) and a lower pressure drop (55 Pa) than the pure PA6 membranes (with values of 94.634% and 467 Pa, respectively). This suggested a new method for high‐efficiency and low‐pressure‐drop filtration applications. Correlations between the filtration pressure drop and filtration efficiency with the structure of the membranes, particle size, and surface velocity were proposed, and the advantage of the multilevel‐layered structure is also discussed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44716.     

Nanofibrous nonwovens based on dendritic‐linear‐dendritic poly(ethylene glycol) hybrids

Dendritic‐linear‐dendritic (DLD) hybrids are highly functional materials combining the properties of linear and dendritic polymers. Attempts to electrospin DLD polymers composed of hyperbranched dendritic blocks of 2,2‐bis(hydroxymethyl) propionic acid on a linear poly(ethylene glycol) core proved unsuccessful. Nevertheless, when these DLD hybrids were blended with an array of different biodegradable polymers as entanglement enhancers, nanofibrous nonwovens were successfully prepared by electrospinning. The pseudogeneration degree of the DLDs, the nature of the co‐electrospun polymer and the solvent systems used for the preparation of the electrospinning solutions exerted a significant effect on the diameter and morphology of the electrospun fibers. It is worth‐noting that aqueous solutions of the DLD polymers and only 1% (w/v) poly(ethylene oxide) resulted in the production of smoother and thinner nanofibers. Such dendritic nanofibrous scaffolds can be promising materials for biomedical applications due to their biocompatibility, biodegradability, multifunctionality, and advanced structural architecture. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45949.     

Effect of nanocrystalline cellulose addition on needleless alternating current electrospinning and properties of nanofibrous polyacrylonitrile meshes

Needleless alternating current (AC)‐electrospinning is capable of achieving high nanofiber generation rates while adding more flexibility to the process development when compared to common direct current (DC)‐electrospinning. However, AC‐electrospinning process may produce very different results than DC‐electrospinning when using the same precursors. This study demonstrated that stable AC‐electrospinning of uniform and mechanically strong polyacrylonitrile (PAN) nanofibrous meshes can be achieved at 30 ± 5 kV rms voltage when 0.75–6.0 wt % of nanocrystalline cellulose‐II with respect to PAN is added to a typical PAN precursor solution. Efficient generation (up to 2 g/h rate or 0.7 g h^?1 cm^?2 mass flux) of nanofibers with 250–500 nm fiber diameters has been observed when using flat fiber‐generating electrodes with diameters up to 25 mm. Depending on the amount of nanocellulose, nanofibrous nanocellulose/PAN meshes revealed large variations in tensile modulus (90–273 MPa) and yield strength (1.0–2.5 MPa), whereas the fiber diameter, air permeability, air resistance, mesh porosity, and water absorption were less affected. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45772.     

Novel core‐sheath antimicrobial nanofibrous mats

The poor mechanical properties of electrospun materials remain one of the major hindrances toward their practical application. In this study, we report the synthesis of core‐sheath nanofibrous mats to enhance the mechanical properties of an antimicrobial polymer nanofiber for application in filter media. This objective was achieved via coaxial electrospinning of poly[styrene‐co‐N‐(N′,N′‐dimethyl‐3‐aminopropyl)maleimide] as the sheath which is an antimicrobial polymer and nylon 6 polymer for the core which is well reported for exceptional mechanical properties. Extensive characterization of these fibers was performed using scanning electron microscopy, scanning transmission electron microscopy, confocal fluorescence microscopy as well as attenuated total reflectance Fourier transform spectroscopy to provide evidence of the core‐sheath morphology. Antimicrobial evaluation was also carried out on the fabricated fibers via the live/dead fluorescence technique. This was done to determine if the poly[styrene‐co‐N‐(N′,N′‐dimethyl‐3‐aminopropyl)maleimide] retained its antimicrobial activity. The fibers were found to be effective against the Gram‐positive Staphylococcus aureus (ATCC25925) and Gram‐negative Pseudomonas aeruginosa (ATCC27853). Subsequent tensile testing and filtration experiments provided evidence that the incorporation of the nylon core improved mechanical properties of the nanofiber mats. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46303.     

Electrospun waterproof breathable membrane with a high level of aerosol filtration

In this study, several nanofibrous polyurethane (PU) webs were electrospun (ES) by changing different effective parameters (e.g., polymeric concentration, voltage, feed flow, etc.). The physical–chemical properties of the webs (i.e., average fiber diameters, thickness, areal density, porosity, contact angle, waterproofness, air permeability (AP), water vapor transmittance, and aerosol filtration) were studied based on the standard test methods. A commercially available waterproof breathable (WPB) fabric was used as a reference for benchmarking. The beads‐free webs with an average fiber diameter as small as 200 nm were achieved from electrospinning of 10 wt % PU in N,N‐dimethylformamide, at feed rate of 0.5 mL/h, applied voltage of 25 kV, and tip‐to‐collector distance of 15 cm. By optimizing the electrospinning parameters, a web with a high level of waterproofness, high AP, and high water vapor transmission rate (WVTR) was obtained. In addition, the selected ES membrane showed very promising aerosol filtration efficiency with complete removal of particles larger than 0.5 µm, and 94% reduction in the concentration of smaller particles. We found a linear empirical equation for the estimation of AP and WVTR based on the average pore size diameter, the membrane thickness, and the porosity with very high regression coefficients (R² > 0.97). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45660.     

Polydimethylsiloxane‐modified polyurethane–poly(ɛ‐caprolactone) nanofibrous membranes for waterproof,breathable applications

In this study, we prepared polydimethylsiloxane (PDMS)‐modified polyurethane–poly(?‐caprolactone) nanofibrous membranes with excellent waterproof, breathable performances via an electrospinning technique. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and mechanical testing were used to characterize the morphologies and properties of the composite nanofibers. The fiber diameter and porous structure of the membranes were regulated by the adjustment of the temperatures of thermal treatment and the PDMS concentrations. The fibrous membranes obtained at a typical temperature of 70 °C possessed an optimized fibrous structure with a diameter of 514 ± 2 nm, a pore size of 0.55–0.65 µm, and a porosity of 77.7%. The resulting nanofibrous membranes modified with 5 wt % PDMS were endowed with good waterproof properties (water contact angle = 141 ± 1°, hydrostatic pressure = 73.6 kPa) and a high breathability (air permeability rate = 6.57 L m^?2 s^?1, water vapor transmission rate = 9.03 kg m^?2 day^?1). Meanwhile, the membranes exhibited robust mechanical properties with a high strength (breakage stress = 11.7 MPa) and excellent thermal stability. This suggests that they would be promising candidates for waterproof, breathable applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46360.     

Tri‐ammonium end functional polyethylene: facile synthesis and application as an intercalation agent

Organo‐modification of montmorillonite (MMT) is crucial for the promotion of a fine dispersion of MMT into an (often hydrophobic) polymer matrix. Ammonium‐terminated polymers are more efficient in modifying clay compared to small organic cations such as alkyl ammoniums or side functionalized polymers. Herein, tri‐amino end functional polyethylene (PE‐3 N) with low molecular weight was first synthesized via an efficient and robust epoxide ring‐opening reaction by treating epoxide‐terminated PE with diethylenetriamine. The chemical structure of PE‐3 N was unambitiously characterized by chromatographic and spectral methods. By reacting with excess HCl, PE‐3 N was subsequently converted to tri‐ammonium end functional polyethylene (PE‐3 N⁺), which serves as an intercalation agent of MMT. By adjusting the weight ratio of PE‐3 N⁺ to pristine MMT (R_P/M) applied in the static melt intercalation process, correlations between the extent of exfoliation and R_P/M were successfully established. XRD results revealed that complete exfoliation of MMT could be afforded with R_P/M as low as 1, which is the lowest value ever reported for ammonium‐terminated polymers applied as intercalation agents. SEM micrographs showed that MMT sheets were swollen by PE‐3 N⁺, affirming the successful modification of MMT. The PE modified MMT obtained may find application in preparing high‐performance PE/MMT nanocomposites. © 2017 Society of Chemical Industry     

Sea‐island polyurethane/polycarbonate composite nanofiber fabricated through electrospinning

Sea‐island polyurethane (PU)/polycarbonate (PC) composite nanofibers were obtained through electrospinning of partially miscible PU and PC in 3 : 7 (v/v) N,N‐dimethylformamide (DMF) and tetrahydrofuran (THF) mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were influenced by composition ratio in the binary mixtures. The pure PC nanofiber was brittle and easy to break. With increasing the PU content in the PU/PC composite nanofibers, PU component not only facilitated the electrospinning of PC but improved the mechanical properties of PU/PC nanofibrous mats. In a series of nanofibrous mats with varied PU/PC composition ratios, PU/PC 70/30 showed excellent tensile strength of 9.60 Mpa and Young's modulus of 55 Mpa. After selective removal of PC component in PU/PC composite nanofibers by washing with acetone, the residual PU maintained fiber morphology. However, the residual PU nanofiber became irregular and contained elongated indents and ridges along the fiber surface. PU/PC composite fibers showed sea‐island nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. At PC content below 30%, the PC domains were small and evenly dispersed in the composite nanofibers. As PC content was over 50%, the PC phases became large elongated aggregates dispersed in the composite nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Prediction of the Elution Profile of Aromatic Compounds in RP‐HPLC

Abstract

An efficient prediction method for the elution profile was used to separate aromatic compounds such as benzene, toluene, chlorobenzene, o‐xylene, and 1,2‐dichlorobenzene by RP‐HPLC. The retention factor and bandwidth were predicted under linear‐gradient condition with the three retention models. The elution profiles were calculated based on the linear and quadratic equations of retention factor, lnk=lnk _w +S?, lnk=L+M?+N?², k=A+B/?, where ? was the vol.% of methanol. The elution profiles were calculated by the Gaussian distribution with obtained retention factor and bandwidth. Two kinds of experiments were performed; one is the isocratic runs to estimate the coefficients of three retention models, and the other is the linear gradient runs that were carried out with same initial mobile phase composition (water/methanol=96/4, vol.%), two final mobile phase compositions (water/methanol=24/76 and 40/60, vol.%), and three gradient times (20, 40, and 60 min). The predicted elution profiles by the three retention models and new prediction method have good agreement with experimental data in the employed gradient conditions. The minimum average errors of calculated and experimental results of aromatic compounds were lower than 3.5% by Bi‐poly equation.     

Stabilized electrospinning of heat stimuli/in situ crosslinkable nanofibers and their self‐same nanocomposites

We present a strategy for stabilizing the morphological integrity of electrospun polymeric nanofibers by heat stimuli in situ crosslinking. Amorphous polymer nanofibers, such as polystyrene (PS) and its co‐polymers tend to lose their fiber morphology during processing at temperatures above their glass transition temperature (T_g) typically bound to happen in nanocomposite/structural composite applications. As an answer to this problem, incorporation of the crosslinking agents, phthalic anhydride (PA) and tributylamine (TBA), into the electrospinning polymer solution functionalized by glycidylmethacrylate (GMA) copolymerization, namely P(St‐co‐GMA), is demonstrated. Despite the presence of the crosslinker molecules, the electrospinning polymer solution is stable and its viscosity remains unaffected below 60 °C. Crosslinking reaction stands‐by and can be thermally stimulated during post‐processing of the electrospun P(St‐co‐GMA)/PA‐TBA fiber mat at intermediate temperatures (below the T_g). This strategy enables the preservation of the nanofiber morphology during subsequent high temperature processing. The crosslinking event leads to an increase in T_g of the base polymer by 30 °C depending on degree of crosslinking. Crosslinked nanofibers are able to maintain their nanofibrous morphology above the T_g and upon exposure to organic solvents. In situ crosslinking in epoxy matrix is also reported as an example of high temperature demanding application/processing. Finally, a self‐same fibrous nanocomposite is demonstrated by dual electrospinning of P(St‐co‐GMA) and stabilized P(St‐co‐GMA)/PA‐TBA, forming an intermingled nanofibrous mat, followed by a heating cycle. The product is a composite of crosslinked P(St‐co‐GMA)/PA‐TBA fibers fused by P(St‐co‐GMA) matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44090.     

Mixed‐cation LiCa‐LSX zeolite with minimum lithium for air separation

The aim of this work was to reduce/minimize Li in Li‐LSX by replacing the 70% Li⁺ cations in Li‐LSX that are bonded to the interior or inaccessible sites which are not used for adsorption. Thus, mixed‐cation LiCa‐LSX containing minimum lithium were prepared by exchanging small fractions of Li⁺ into Ca‐LSX, followed by dehydration under mild conditions to avoid migration/equilibration of Li cations. Comparisons of adsorption isotherms of N₂/O₂ and heats of adsorption for the LiCa‐LSX samples with that for pure‐cation Li‐LSX and Ca‐LSX provided strong evidence that significant amounts of these Li cations indeed remained on the exposed sites (SIII). The mixed‐cation LiCa‐LSX samples were compared against the pure‐cation Ca‐LSX and Li‐LSX based on their performance for oxygen production by PSA, via model simulation. The results showed that the mixed‐cation LiCa‐LSX samples yielded significantly higher O₂ product productivities at the same product purity and recovery than their pure‐cation precursor (Ca‐LSX). © 2017 American Institute of Chemical Engineers AIChE J, 64: 406–415, 2018     

Electrospinning of polycaprolactone nanofibers using H2O as benign additive in polycaprolactone/glacial acetic acid solution

Considerable efforts have been devoted to the production of polycaprolactone (PCL) nanofibrous structures by electrospinning. However, some toxic solvents have often been used to achieve bead‐free nanofibers. At present, a benign solvent such as glacial acetic acid (GAC) only leads to beaded or microscale fibers. Therefore a study is done to extend the electrospinnability of the PCL/GAC system by the addition of H₂O. The solution properties of conductivity, viscosity, and surface tension were altered by the addition of H₂O, especially increasing the conductivity and viscosity. These properties essential to electrospinning could remain stable for 6 h when the H₂O content was less than or equal to 9 vol %. Then ultrafine PCL fibers with diameters from 188 to 200 nm, 10 times smaller than when dissolved in pure GAC, were electrospun from solutions of PCL with concentrations in the range of 17 to 20 wt % with H₂O content at 9 vol %. Finally, the crystallinity and crystallite size of the resulting fibers were smaller than that of raw PCL pellets. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45578.     

Preparation and characterization of polyhydroxybutyrate‐co‐hydroxyvalerate/silk fibroin nanofibrous scaffolds for skin tissue engineering

Nanofibrous scaffolds were obtained by co‐electrospinning poly (3‐hydroxybuty‐rate‐co‐3‐hydroxyvalerate) (PHBV) and fibroin regenerated from silk in different proportions using 1,1,1,3,3,3‐hexafluoro‐2‐isopropanol (HFIP) as solvent. Field emission scanning electron microscope (FESEM) investigation showed that the fiber diameters of the nanofibrous scaffolds ranged from 190 to 460 nm. X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy analysis (FT‐IR) showed that the main structure of silk fibroin (SF) in the nanofibrous scaffold was β‐sheet. Compared to the PHBV nanofibrous scaffold, the surface hydrophilicity and water‐uptake capability of the PHBV/SF nanofibrous scaffold with 50/50 were improved. The results of cell adhesion experiment showed that the fibroblasts adhered more to the PHBV/SF nanofibrous scaffold with 50/50 than the pure PHBV nanofibrous scaffold. The proliferation of fibroblast on the PHBV/SF nanofibrous scaffold with 50/50 was higher than that on the pure PHBV nanofibrous scaffold. Our results indicated that the PHBV/SF nanofibrous scaffold with 50/50 may be a better candidate for biomedical applications such as skin tissue engineering and wound dressing. POLYM. ENG. SCI., 55:907–916, 2015. © 2014 Society of Plastics Engineers     

Preparation of Sn‐doped CdS/TiO2/conducting polymer fiber composites for efficient photocatalytic hydrogen production under visible light irradiation

Sn‐doped CdS/TiO₂ heterojunction was synthesized on the conducting polymer fiber mat by hydrothermal method. The conducting polymer fiber mat was made by electrospinning from polyvinylidene fluoride, styrene‐maleic anhydride copolymer, and nano‐graphites as conducting fillers. The Sn‐doped CdS/TiO₂ heterojunction was characterized by XRD, XPS, SEM, TEM, TGA, and UV–Vis absorption spectra. Under simulated solar light irradiation, a combination of Sn‐doped CdS/TiO₂/conducting polymer was found to be highly efficient for photocatalytic hydrogen evolution from splitting of water. The photocatalytic hydrogen production efficiency was up to 2885 μmol h^?1 g^?1cat. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42300.