Electrospun Cellulose Acetate Fibers Research Articles

Cellulose acetate fibers as corrosion inhibitor delivery system for carbon steel

This study evaluated the effectiveness of electrospun cellulose acetate fibers (CAFs) containing oleic acid (OA) for corrosion inhibition on carbon steel in chloride-rich environments. By varying the OA content, CAFs of different thicknesses were produced. Potentiodynamic polarization showed that steel coated with OA-containing CAFs had enhanced corrosion resistance, with higher corrosion potential (Ecorr) and lower corrosion current density (icorr). The electrochemical impedance spectroscopy (EIS) results for the dip-coated sample showed an impedance increase of approximately 20× (from 2 to 40 kΩ cm2), and a capacitance reduction from 10−6 to 10−8 F cm−2, compared to the untreated sample. The protective effect remained even after 48 h of exposure. These findings suggest CAFs as effective carriers for delivering OA inhibitors, offering a promising solution for corrosion mitigation in saline environments.

Carbon Threads Supercapacitors for Washable e-Textile Applications: Configurations and Electrochemical Performance.

Technological solutions for emerging e-textiles are being sought to enable e-wear technology to be self-sustaining and lightweight. A rippling 1D carbon fiber capacitor design was made with commercial carbon threads as electrodes using simulated sweat solution as the electrolyte. This is particularly relevant for potential sports textile applications in which sweat could serve as an electrochemical energy source. An electrospun cellulose acetate fiber membrane and a commercially available felt were used as separators capable of soaking the electrolyte. These were tested in braided and woven electrode configurations, respectively. Functionalizing the carbon wires with polypyrrole (PPy) enhanced the surface area and significantly increased the specific capacity by approximately an order of magnitude (0.62 F/g). Cyclic voltammetry and charge-discharge tests confirmed the washability and durability of the devices for at least 1000 cycles.

Electrospun Cellulose Acetate Nanofibers Containing Clinacanthus nutans (Phayayo) Crude Extract as Potential Wound Dressings

Extraction of Clinacanthus nutans (Burm.f.) lindau (C. nutans) or Phayayo (PY) leaves was performed by maceration using ethanol as an extractant. The antioxidant activity was evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. The inhibitory concentration at 50% antioxidant activity (IC50) of PY extract was 15.62 mg/mL. The electrospun cellulose acetate (CA) nanofibers containing PY extract at concentrations of 2.5, 5, and 7.5% w/v and silver (Ag) nanoparticles at 0.1% w/v were fabricated. The addition of PY extract and Ag influenced the viscosities of solutions and therefore affected the morphology and fiber diameters. The electrospun CA fiber mat containing 0.1% Ag and 7.5% PY extract was chosen to investigate its potential for use in wound dressing applications. The degrees of weight loss and water swelling of the electrospun CA/PY7.5/Ag fiber mat after immersion in a phosphate buffer solution (pH 7.4) at 37°C were examined in a range of 2-24 h, and found to increase with immersion time. The antioxidant activity of the fiber mat at the same period of immersion time was also studied, which corresponded with the trends of weight loss and water swelling. The antioxidant activity at 24 h of immersion was 68.3±9.2%. The CA/PY7.5/Ag fiber mat had no antibacterial activity against Escherichia coli but slightly inhibited the growth of Staphylococcus aureus. The fiber mat also possesses high hydrophilicity, as examined by the contact angle measurement. These results indicate that the CA/PY7.5/Ag fiber mat is a promising material for use as a topical transdermal patch or wound dressing.

Sputtering deposition under limited adatom mobility: an effective method to prepare a SERS substrate based on Ag@ZnO composite deposited onto electrospun cellulose acetate fibers

Sputtering deposition under limited adatom mobility: an effective method to prepare a SERS substrate based on Ag@ZnO composite deposited onto electrospun cellulose acetate fibers

Fabrication of Electrospun Cellulose Acetate/Nanoclay Composites for Pollutant Removal.

The creation of eco-friendly clay-based composites for pollutant removal by adsorption still remains a challenge. This problem might be successfully solved by the development of electrospun polymer-clay composites. For the first time in this study, a one-step fabrication of cellulose acetate (CA) fibers filled with commercially available nanoclays (NCs) was described. The optimal ratio at which CA/NCs dispersions remained stable was accomplished by varying the nanoclay concentration with respect to CA. Furthermore, the selected solvent system and the electrospinning conditions allowed for the successful fabrication of electrospun CA/NC composites. It was found that the composites' surface morphology was not affected by the incorporated nanoclays and was the same as that of the electrospun CA fibers. The performed analyses clearly showed that CA and nanoclays did not react during the electrospinning process. It was found that the distribution of nanoclay layers probably was a mixture of intercalated and exfoliated structures. Notably, the type of the nanoclay strongly influenced the adsorption ability of CA/NC composites toward Cr(VI) ions and MB dye. These results suggested that the fabricated CA/NC composites are suitable for pollutant removal due to their specific structure.

Fabrication of Photoactive Electrospun Cellulose Acetate Nanofibers for Antibacterial Applications

The aim of the study was to investigate the process of electrostatic fabrication of cellulose acetate (CA) nanofibers containing methylene blue (MB) as a photosensitizer. The electrical, physicochemical, and biocidal properties of the prepared material were given. CA nanofibers were prepared by electrospinning method using a solvent mixture of acetone and distilled water (9:1 vv−1) and different concentrations of CA (i.e., 10–21%). Additionally, methylene blue was implemented into the polymer solution with a CA concentration of 17% to obtain fibers with photo-bactericidal properties. Pure electrospun CA fibers were more uniform than fibers with MB (i.e., ribbon shape). Fiber diameters did not exceed 900 nm for the tested polymer solutions and flow rate below 1.0 mL h−1. The polymer properties (i.e., concentration, resistivity) and other parameters of the process (i.e., flow rate, an applied voltage) strongly influenced the size of the fibers. Plasma treatment of nanofibers resulted in reduced biofilm formation on their surface. The results of photo-bactericidal activity (i.e., up to 180 min) confirmed the high efficiency of inactivation of Staphylococcus aureus cells using fibers containing methylene blue (i.e., with and without plasma treatment). The most effective reduction in the number of biofilm cells was equal to 99.99 ± 0.3%.

Fabrication and characterization of composite film based on gelatin and electrospun cellulose acetate fibers incorporating essential oil

In this research, Oliveria decumbens Vent essential oil (OEO) at 0–45% w/w was encapsulated in cellulose acetate (CA) electrospun fibers and then incorporated in gelatin-based films. Scanning Electron Microscope (SEM) showed more uniform and compact surface in the neat gelatin film in comparison to the CA fiber loaded composite ones and microfibers were perpendicular to the fracture surface. The composites showed higher tensile strength (1.3–2.6 MPa) and lower elongation (less than 1%) than the pure gelatin film. Water solubility of the composites were significantly lower than the gelatin film (81% VS. ≈50%). The water vapor permeability (WVP) of composites was higher than the gelatin film probably due to microscopic pinholes induced by fibers, however WVP slightly decreased by increasing OEO. The contact angle values from 79.9 to 101.5° indicating increase of hydrophobicity by incorporating the CA fibers. Inhibition zones against E. coli and S. aureus (13.33 mm) confirmed the antibacterial activity of composites. It can be concluded that the composite gelatin films incorporating EO-loaded electrospun fibers could enhance the mechanical and antimicrobial properties of the composites despite increasing WVP, thus they could be potentially used for food active packaging purposes.

Electrospun cellulose acetate fibers for the photodecolorization of methylene blue solutions under natural sunlight

Cellulose acetate (CA) fibers were obtained by electrospinning and their properties analyzed by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermogravimetric analysis. The effect of the polymer concentration on crystallinity and fiber diameter of the obtained material was studied by DSC. The application of the pure polymeric fibers to the discoloration of methylene blue (MB) aqueous solutions in dark and under sunlight irradiation was evaluated with UV–Vis absorption and photoluminescence spectroscopies. Also, the photodegradation of the dye was compared using CA powder and fibers under UV irradiation. The results revealed that the dye molecule discoloration with CA fibers mesh was higher under sunlight irradiation than in dark conditions. The maximum absorption band (664 nm) of MB decreased with the time in the absence and presence of polymer under either solar natural exposition or UV irradiation. The dye organic discoloration efficiency obtained by using electrospun CA mesh was 28% and 98% in dark conditions and under natural solar illumination, respectively. The FTIR showed the interaction of dye organic or sub-products generated with the polymeric component. This work provides a simple method for the discoloration of wastewater effluents using microfibers composed of only one abundant polymeric material, allowing the reduction in the amount of material needed and therefore the manufacturing costs of the adsorbent material.

Carbon threads sweat-based supercapacitors for electronic textiles

Flexible and stretchable energy-storage batteries and supercapacitors suitable for wearable electronics are at the forefront of the emerging field of intelligent textiles. In this context, the work here presented reports on the development of a symmetrical wire-based supercapacitor able to use the wearer’s sweat as the electrolyte. The inner and outer electrodes consists of a carbon-based thread functionalized with a conductive polymer (polypyrrole) which improves the electrochemical performances of the supercapacitor. The inner electrode is coated with electrospun cellulose acetate fibres, as the separator, and the outer electrode is twisted around it. The electrochemical performances of carbon-based supercapacitors were analyzed using a simulated sweat solution and displayed a specific capacitance of 2.3 F.g−1, an energy of 386.5 mWh.kg−1 and a power density of 46.4 kW.kg−1. Moreover, cycle stability and bendability studies were performed. Such energy conversion device has exhibited a stable electrochemical performance under mechanical deformation, over than 1000 cycles, which make it attractive for wearable electronics. Finally, four devices were tested by combining two supercapacitors in series with two in parallel demonstrating the ability to power a LED.

UV random laser emission from flexible ZnO-Ag-enriched electrospun cellulose acetate fiber matrix

We report an alternative random laser (RL) architecture based on a flexible and ZnO-enriched cellulose acetate (CA) fiber matrix prepared by electrospinning. The electrospun fibers, mechanically reinforced by polyethylene oxide and impregnated with zinc oxide powder, were applied as an adsorbent surface to incorporate plasmonic centers (silver nanoprisms). The resulting structures – prepared in the absence (CA-ZnO) and in the presence of silver nanoparticles (CA-ZnO-Ag) - were developed to support light excitation, guiding and scattering prototypes of a RL. Both materials were excited by a pulsed (5 Hz, 5 ns) source at 355 nm and their fluorescence emission monitored at 387 nm. The results suggest that the addition of silver nanoprisms to the ZnO- enriched fiber matrix allows large improvement of the RL performance due to the plasmon resonance of the silver nanoprisms, with ~80% reduction in threshold energy. Besides the intensity and spectral analysis, the RL characterization included its spectral and intensity angular dependences. Bending the flexible RL did not affect the spectral characteristics of the device. No degradation was observed in the random laser emission for more than 10,000 shots of the pump laser.

Hydrophilic and Insoluble Electrospun Cellulose Acetate Fiber-Based Biosensing Platform for 25-Hydroxy Vitamin-D3 Detection

The present work describes the fabrication of a simple, low-cost, eco-friendly, and disposable conducting paper substrate (RCP) decorated with electrospun cellulose acetate fibers (CAEFs) for biosensor application. CAEFs were electrospun under spinning conditions at a voltage of 16 kV, flow rate of 0.2 mL h–1, and tip-to-collector distance of 15 cm. CAEFs were directly collected onto RCP. A scanning electron microscopy study revealed the diameter of CAEFs in the range of 330 ± 3.50 nm. The contact angle of CAEFs was found to be 38.07 ± 5.10°, which indicates a hydrophilic nature of the fibers. Further, the CAEF/RCP electrode was modified with antibody specific to 25-hydroxy vitamin-D3 (AB-25OHD3), followed with bovine serum albumin (BSA) to block nonspecific binding sites for detection of 25-OH vitamin-D3. The BSA/AB-25OHD3/CAEF/RCP immunoelectrode fabrication was confirmed thorough scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle and electrochemical techniques. The chr...

Understanding solubility, spinnability and electrospinning behaviour of cellulose acetate using different solvent systems

The purpose of this study is to understand the solubility and spinnability of cellulose acetate (CA) and its electrospinning behaviour in different solvents. As the process of electrospinning and the corresponding fibre properties are primarily governed by the solvents used, a systematic study of the selection of solvent systems using the solubility parameters of Hildebrand and Hansen along with a Teas chart for a particular polymer is essential for the better optimization of the process. It appeared from the Teas chart that higher dispersion force \((f_{\mathrm{d}})\) and lower hydrogen bonding force \((f_{\mathrm{h}})\) are convenient for both the solubility and spinnability of CA in single solvent of acetone and binary solvent of 2:1 acetone/N,N-dimethylacetamide (DMAc). The viscosity of the solutions escalated with increasing concentration of CA due to polymer chain entanglement which in turn favoured fibre formation. Among the solvent systems used in this work, field emission scanning electron microscopy arrayed the electrospun CA fibres using pure acetone as a solvent produced both cylindrical- and ribbon-shaped fibres of a diameter of 1 \(\upmu \)m, whereas CA in 2:1 acetone/DMAc yielded smooth bead-free cylindrical fibres of diameter in the range of 250–350 nm and CA in 3:1 acetic acid/water formed fibres with beads. Rheological analysis showed that fibre formation improved with increasing viscosity of CA solution. Electrical conductivity measurement of the CA solutions depicted that with an increase in CA concentration, fibre diameters were increased, whereas the conductivity decreased. Also, attenuated total reflectance–Fourier transform infrared spectroscopy confirmed the major peaks of CA for all the electrospun samples.

Assembly of odour adsorbent nanofilters by incorporating cyclodextrin molecules into electrospun cellulose acetate webs

A significant problem in ventilating domestic or commercial kitchens is the removal and separation of volatile compounds which we perceive as strong smells of the sort particularly emitted whilst frying food. In this research, the feasibility of preparing enriched electrospun cellulose acetate (CA)-based nanofibres containing cone-shaped molecules of beta-cyclodextrin (β-CD) for the adsorption of the very strong and sharp aldehyde odour of hexanal, which is a marker for oil and fat oxidation was investigated. A binary solvent system using acetone: DMF (2:1) was shown to be suitable for solution blending of CA with β-CD. Nanofibrous webs were continuously produced and found to be substantially free of defects such as beading, producing fibres with the average diameters of 773 ± 50 nm in the range: 250–1.5 μm. Colorimetry was used to show the entrapment of β-CD in the CA structure. The encapsulation efficiency of β-CD in the fibre structures was typically 85%. FTIR of the electrospun nanofibres examining the fingerprint region of CA indicating no structural changes in the CA during processing. Our results show that electrospun CA fibres embedded with β-CD molecules demonstrate enhanced direct adsorption of model odour material hexanal (up to 80%) indicating feasibility for use in filtration.

Electrospun ultra-fine cellulose acetate fibrous mats containing tannic acid-Fe3+ complexes

Cellulose acetate (CA) fibrous mats with improved mechanical and antioxidant properties were produced by a simple, scalable and cost-effective electrospinning method. Fibers loaded with small amounts of TA-Fe3+ complexes showed an increase in tensile strength of ∼117% when compared to that of neat CA and were more resistant than those loaded with TA alone. The water uptake of the fibers increased upon TA or TA-Fe3+ incorporation while their thermal behavior was only slightly affected. Fibrous mats loaded with TA-Fe3+ showed comparable antioxidant activity with that of CA/TA mats, and a much slower TA release. These results suggest that TA-Fe3+ complexes can be incorporated into electrospun CA fibers to improve their mechanical properties and antioxidant activity which may be of interest for the development of active packaging that can extend the shelf life of perishable foods.

Electrospun Cellulose Acetate Fiber Mats as Carriers for Crude Extracts From Phyllanthus Emblica Linn. Fruits

Fruit of Phyllanthus emblica Linn (PE) was extracted with methanol and then partitioned into diethyl ether, ethyl acetate, butanol, and water fractions. The diethyl ether fraction showed the highest antibacterial activity against two pathogenic bacteria including Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923). The PE extract from diethyl ether fraction was then loaded into 17%w/v cellulose acetate (CA) solution prepared in 2:1 v/v acetone/ N, N -dimethylacetamide at concentrations of 1, 3, and 5% w/w (based on the weight of CA). The PE extract-loaded electrospun CA fiber mats were fabricated by electrospinning. The morphological appearance of both the neat and the PE extract-loaded electrospun CA fibers were smooth with the average diameters in a range of 335-694 nm. The amounts of water retention and release characteristics of PE extract from fiber mats in an acetate buffer (pH 5.5) were studied and compared with the corresponding cast-films fabricated by the solvent casting method. The amount of water retention of the PE extract-loaded fiber mats was about 112-205% which was higher than that of the cast films (i.e. 25-35%). The study of release characteristics of PE extract from fiber mats and films was carried out by total immersion method in an acetate buffer at 32°C for 72 h. The PE extract-loaded fiber mats exhibited greater amount of extract released than those of the cast films. The maximum amounts of PE extract released from fiber mats and films were about 40-80% and 18-23%, respectively.

Parametric Study of Electrospun Cellulose Acetate in Relation to Fibre Diameter

The objective was to identify the main factors and interactions influencing the fibre diameter in the production of electrospun cellulose acetate (CA) webs. A systematic parameter study was completed for producing electrospun CA fibres that were substantially free of bead defects and the effect of different process parameters during electrospinning CA were evaluated in respect of mean fibre diameter. The experiments were planned using factorial designs. Altogether three parameters, each at three levels, were selected for this study. The results indicate that polymer concentration, voltage and flow rate interact so that the magnitude of any change in the mean fibre diameter is dependent upon the level of the other factors. Furthermore, stable electrospinning conditions for CA were confirmed using an acetone: N, N-dimethylacetamide (DMAc) (2:1) solvent system that minimised the presence of structural defects in the web and promoted uniform fibre diameters.

Aerosol filtration using electrospun cellulose acetate fibers

Aerosol filtration using electrospun cellulose acetate filters with different mean fiber diameters is reported, and the results are compared with those for two conventional filter media, a glass fiber filter and a cellulose acetate microfiber filter. The performance of these filters was studied using two aerosols, one solid (NaCl) and one liquid (diethyl hexyl sebacate), under conditions of relatively high face velocity (45 cm/s). The experimental observations are compared to theoretical predictions based on single fiber filtration efficiency. Our results indicate that the mechanisms for single fiber filtration efficiency provide reasonable predictions of the most penetrating particle size (MPPS), in the range of 40–270 nm, percentage penetration from 0.03 to 70 %, and fiber diameter in the range from 0.1 to 24 µm. Using an analysis based on blocking filtration laws, we conclude that filtration by cake formation dominated in the case of NaCl aerosols on electrospun filter media, whereas filters with larger fiber diameter showed a transition in mechanisms, from an initial regime characterized by pore blocking to a later regime characterized by cake formation. The liquid aerosol did not exhibit cake formation, even for the smallest fiber diameters, and also had much smaller influence on pressure drop than did the solid aerosol. The electrospun filters demonstrated slightly better quality factors compared to the commercial glass fiber filter, at a much lower thickness. In general, this study demonstrates control of the properties of electrospun cellulose acetate fibers for air filtration application.

Controlled‐release drug carriers based hierarchical silica microtubes templated from cellulose acetate nanofibers

ABSTRACTWe report a facile method to synthesize hollow silica microtubes (SMTs) from electrospun cellulose acetate fiber precursors. Specific surface areas of up to 765 m2/g (Brunauer–Emmett–Teller) were measured for the SMTs, which had a typical wall thickness of ∼100 nm and submicron inner diameters. An average pore size of 4.6 nm and pore volume of 0.41 cm3/g were derived from Barrett–Joyner–Halenda fitting, whereas Horvath–Kawazoe pore size distribution analysis revealed microporous median pore size and maximum pore volume of 0.7 nm and 0.18 cm3/g, respectively. The as‐prepared SMTs featuring micro‐ and mesoporous structures in the walls where amino‐functionalized to facilitate a very high drug loading (15% by weight). Drug release profile revealed sustained release rates (79% of acetylsalicylic acid was released after 6 h). It is concluded that the high drug loading and sustained release resulted from the advantageous integration of SMTs' hollow structure and wall mesoporosity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42562.

Ionic liquid assisted electrospun cellulose acetate fibers for aqueous removal of triclosan.

The cellulose acetate (CA) membrane prepared via electrospun was innovatively utilized as fiber-adsorbent for the separation of aqueous triclson (TCS). It was found that the presence of the room temperature ionic liquid (RTIL) in the precursor amplified electric force toward the CA-solution, thereby benefiting the formation of CA fibers. The as-spun CA fibers exhibit excellent adsorptive performance toward TCS, with fast adsorption kinetics, and the maximum adsorption capacity achieved to 797.7 mg g(-1), which established much better performance in contrast to conventional adsorbents. We proposed that the adsorption of TCS onto CA fibers was primarily facilitated by the hydrogen bonding between the abundant carbonyl, hydroxyl groups of CA surface, and the hydrogen atoms of phenol functional groups in TCS molecular.

Tensile mechanical properties and hydraulic permeabilities of electrospun cellulose acetate fiber meshes

The mechanical properties and hydraulic permeabilities of biomaterial scaffolds play a crucial role in their efficacy as tissue engineering platforms, separation processors, and drug delivery vehicles. In this study, electrospun cellulose acetate fiber meshes of random orientations were created using four different concentrations, 10.0, 12.5, 15.0, and 17.5 wt % in acetone or ethyl acetate. The tensile mechanical properties and the hydraulic permeabilities of these meshes were measured, and a multiscale model was employed to predict their mechanical behavior. Experimentally, the elastic modulus ranged from 3.5 to 12.4 MPa depending on the polymer concentration and the solvent. Model predictions agreed well with the experimental measurements when a fitted single-fiber modulus of 123.3 MPa was used. The model also predicted that changes in fiber alignment may result in a 3.6-fold increase in the elastic modulus for moderately aligned meshes and a 8.5-fold increase for highly align meshes. Hydraulic permeabilities ranged from 1.4 x 10(-12) to 8.9 x 10(-12) m(2) depending on polymer concentration but not the choice of solvent. In conclusion, polymer concentration, fiber alignment, and solvent have significant impact on the mechanical and fluid transport properties of electrospun cellulose acetate fiber meshes.