Surface Morphology Of Nanofibers Research Articles

Textured nanofibers inspired by nature for harvesting biomechanical energy and sensing biophysiological signals

Flexible electronics are emerging as a promising new platform for wearables; however, their practical utility is hindered by the limited battery life of electronic devices and the need for frequent battery replacements. Here, we report self-powered, flexible, permeable, tough, and lightweight biomechanical energy harvesting and biophysiological sensing devices using textured nanofibers for wearable electronics applications. The textured structure draws inspiration from two major sources of nature: the interior porous structure of jute fibers and the rough bark texture of trees. Interior pores are introduced to the nanofibers to increase compressibility and breathability like jute fibers. The inspiration from the rough bark texture also leads to a wrinkled surface morphology of the nanofibers to expand the surface area and consequently enhance toughness. To design and fabricate such a textured structure, the vapor-induced phase separation mechanism and electrospinning technique are employed within a controllable high humidity environment. Consequently, the textured nanofiber-based devices exhibit a well-rounded performance in electrical, mechanical, and physical properties, specifically demonstrating a significantly enhanced piezoelectric performance with more than two-fold electrical generation. These textured devices not only effectively harvest biomechanical energy from human movement but also demonstrate sensing capability for self-powered multifunctional biophysiological monitoring applications by leveraging the same piezoelectric mechanism. The novel design strategy for the textured nanofibers and their resultant balanced performance promotes the versatility and practical applicability of piezoelectric fibrous energy harvesting and sensing devices, contributing to the development of next-generation flexible and wearable electronics.

A mini-review on wrinkled nanofibers: Preparation principles via electrospinning and potential applications

Tailoring the surface morphology of nanofibers determines its application to an excessive extent. At present, different structures of nanofibers have been produced such as wrinkled, grooved, porous, rough, etc. Amongst them, wrinkled nanofibers have attracted the attention of researchers due to their exceptional structure and properties such as coarse surface, high surface energy, high specific surface area, excellent mechanical properties, and good piezoelectricity resulting in serving successfully in various fields such as energy harvesting, air filtration, water filtration, gas sensors, biomedical applications, fuel cells, and energy storage. Therefore, this work aims to spotlight the importance of the wrinkled structure, methods, and strategies used for producing electrospun wrinkled nanofibers of various materials. This review focuses on the materials, preparation methods, and applications of the electrospun wrinkled nanofibers. This review can serve as an essential reference for the materials, formation methods, and applications of wrinkled nanofibers prepared via electrospinning.

A comprehensive review on branched nanofibers: Preparations, strategies, and applications

Engineering surface morphologies of nanofibers has been attracting significant consideration in numerous fields and applications. Among different methods of generating nanofibers, electrospinning is the most widely adopted technique owing to the ease of forming nanofibers with an extensive range of properties and its exceptional advantages, such as the variety of shapes and sizes, as well as the adaptable porosity of nanofiber webs. The branched structure is considered one of the most attractive structures for scientific researchers due to its outstanding properties (e.g., high-specific surface area and extremely tiny diameters of branched nanofibers). Therefore, this work is the first one that summarizes the strategies and methods, reported so far, of producing branched nanofibers of different materials. The material types, formation mechanisms, characterizations, and applications of the branched nanofibers generated through different techniques will be discussed in detail in this study. We believe this work can be served as an important reference for the preparations, strategies, and applications of the branched nanofibers.

Anticancer efficacy of lupeol incorporated electrospun Polycaprolactone/gelatin nanocomposite nanofibrous mats

Despite the anticancer effect of lupeol (Lup), low aqueous solubility can make its therapeutic usage difficult. However, polycaprolactone/Gelatin (PCL-GEL) nanofibers scaffold eliminates this problem. This study has been conducted to recognize PCL-GEL-Lup nanofibers effect on cancer cell lines. PCL-GEL solution was prepared at different ratios (8 wt% and 4 wt%) for achieving optimal nanofibers. PCL-GEL-Lup nanofibers were provided via electrospinning technique. The surface morphology of nanofibers was examined using FESEM. Functional groups were investigated by a Fourier Transform Infrared spectroscopy. Lupeol released from nanofibers was detected by a UV–Visible spectroscopy. The drug release profile confirmed the sustained release of about 80% achieved within 40 h. IC50 of lupeol against ACHN and HSC-3 cell lines are 52.57 and 66.10 μg ml−1 respectively. The study results from aid an understanding of the fabrication of a scaffold with an optimum dose of bioactive lupeol in 6 wt% with bead free uniform diameter that is capable of binding the drug efficiently. The enhanced cytotoxicity activity by effective diffusion and elution to the target achieved in this study help to develop a nanofiber in the ongoing battle against cancer.

Physicochemical studies of iron/vanadate doped hydroxyapatite/polycaprolactone nanofibers scaffolds

Altering nanofibrous structures to be used for wound healing applications is crucially needed to improve quality of life. Co-substituted hydroxyapatite (HAP) with different iron (Fe)/vanadate (VO43−) ions contributions are involved in polycaprolactone (PCL), where the electrospinning method is used to fabricate PCL polymer. XRD explains both powder and nanofibrous scaffold structural features. The surface morphology for powdered Fe/V-HAP@PCL shows changes in grains size from 1.59–6.26 µm to 2.0–3.76 for the minimum and maximum Fe composition. The roughness average increased by increasing Fe substitution from 37.0 to 56.5 nm, while (Rq) rises from 49.8 to 73.7 nm. The surface morphology of nanofibers shows a diameter range from around 0.97–3.19 µm to 0.44–1.91 µm. Further, the roughness parameter of Ra rose from 34.96 to 59.49 nm. TEM micrographs revealed the diameters of nanofibrous scaffolds are around 200–360 nm. Mechanical parameters vary upon increasing dopant ions in HAP; tensile strength rises from 1.61 ± 0.8 to 4.93 ± 0.8 MPa. Moreover, the contact angle decreased by increasing Fe ion, in which values declined from 101.2 ± 2.5 to 85 ± 4.3°. Enhancing cell viability from 90.3 ± 3.1% to 97.5 ± 2.8% for the minimum and maximum Fe ions composition., The porosity of the nanofibrous surface improved, which illustrated increasing cell growth upon increasing dopant ion. Hence, modulating the nanofibrous scaffold by controlling the composition of doped metal ions could be advantageous for biomedical applications.

Facile synthesis of Veitchia merilli coir-based porous carbon using combined chemical and physical activation routes as electrode material for energy storage

This study aimed to prepare Veitchia merilli coir (VMC) through pre-carbonisation process, followed by chemical activation using potassium hydroxide as an activating agent. The experiment was conducted under different pyrolytic physical activation temperatures of 650, 700, and 750 °C with the code VMS-650, VMS-700, and VMS-750 for each sample. Physical activation methods develop or modify the pore structure, specific surface area, and microstructure of activated carbon. Furthermore, the prepared VMCs were characterised using X-ray diffraction, Fourier transform infrared, scanning electron microscope, energy dispersive X-ray, and cyclic voltammetry with a symmetrical two-electrode system in 1 M H2SO4 solution. The microstructure analysis showed that the VMC carbon electrode has an amorphous structure with two broad peaks at 2θ angles around 26° and 44° corresponding to the (002) and (100) planes, with the L c VMS-700 having a value of 16.007 nm. The VMC electrode has a C≡C carbon bond as a functional group, which extends in bands from 2311.79 to 2373.51 cm−1. Meanwhile, the VMS-700 electrode shows a combined surface morphology of nanofibers as well as mesopores, and the energy dispersive X-ray results showed carbon content of 92.83%. The electrochemical properties of supercapacitor cells indicated this electrode had the highest specific capacitance value of 264.2 F g−1. From the obtained results, the respective physical and electrochemical properties of the carbon electrodes and supercapacitor cells showed that the activated VMC-700 at 700 °C is the optimum temperature to produce the best performance compared to 650 and 750 °C.

A feasibility study on production and optimization of PVDF/PU polyblend nanofiber layers using expert design analysis

Different polymer blends are electrospun to produce nanofibers with novel combined features. In this study, the feasibility of combining polyurethane (PU) and polyvinilidine floride (PVDF) polymer was evaluated to produce an adequate nanoscale layer. This scale would increase the β-phase in PVDF; the lowest beads in the nanolayers, to achieve a smooth layer with more uniform strength. To manufacture PVDF/PU, the PVDF was combined with PU components for elastic behavior. Eighteen experimental design points were performed using Design-Expert software, based on electrospinning variables, including solution concentration, applied voltage, and the needle to collector distance. SEM study was carried out to assess the fiber diameter and the bead numbers to characterize the surface morphology of nanofibers. Chemical reactions between the two polymer components and the fibers inner structure were investigated through FTIR and XRD. According to the experiment design, 14% (wt) solution concentration, 18 kV voltage, and 24 cm distance between the needle tip and the collector were considered as the optimum conditions during electrospinning. FTIR test revealed that there was no chemical reaction between the TPU and PVDF components. Also, several β-phases were formed during the electrostatic drafting of a polyblend solution. Moreover, the XRD results showed that the PVDF/TPU composite had low crystallinity compared to pure TPU and PVDF. Finally, it was concluded that providing uniform nanofiber mats by applying the optimum condition during electrospinning would result in PVDF/TPU polyblend higher piezoelectric features nanofibers.

Mechanistic aspects for the enhanced adsorption of bromophenol blue and atrazine over cyclodextrin modified polyacrylonitrile nanofiber membranes

The present work describes a unique modification process for electrospun polyacrylonitrile (PAN) nanofiber membranes modified with β-cyclodextrin (β-CD) monomers and their application in the adsorption of bromophenol blue and atrazine from aqueous systems. PAN and β-CD were successfully crosslinked using citric acid followed by electrospinning of PAN-CD nanofiber membranes. XRD and FTIR spectroscopy demonstrated successful crosslinking of PAN, β-CD, and citric acid to form PAN-CD nanofiber membranes. The microstructure and surface morphology of nanofibers were investigated using SEM and AFM and our data show that the nanofibers are uniform, have an average diameter range of 497–557nm and possess rougher surfaces. UV-Vis spectroscopic technique was used to determine the nanofiber membranes’ adsorption efficiency and to evaluate their adsorption capacity. Batch adsorption studies at optimized conditions revealed that the removal of 66% and 89% was achieved for bromophenol blue using PAN and PAN-CD nanofibers with adsorption capacity of 0.886 and 1.197mg/g, respectively. PAN and PAN-CD nanofibers removed 67% and 91% atrazine with adsorption capacity of 0.603 and 0.817mg/g, respectively. The adsorptive removal of these pollutants followed the pseudo-second order kinetics and best fitted the Freundlich isotherm model. The increased removal is therefore credited to the increased surface area per volume ratio obtained from reduced diameters, intermolecular interactions, and inclusion complexation after the incorporation of β-CD monomers. Thus, it is shown that the addition of CDs improved the adsorption capacity of the hybrid materials via distinctive adsorption mechanisms. Thus, the uniqueness of this work lies on the mechanistic adsorption of bromophenol blue and atrazine through modified PAN-CD nanofiber matrix induced by the grafting of citric acid crosslinked β-CD.

Argon and Argon-Oxygen Plasma Surface Modification of Gelatin Nanofibers for Tissue Engineering Applications.

In the present study, we developed a novel approach for functionalization of gelatin nanofibers using the plasma method for tissue engineering applications. For this purpose, tannic acid-crosslinked gelatin nanofibers were fabricated with electrospinning, followed by treatment with argon and argon–oxygen plasmas in a vacuum chamber. Samples were evaluated by using scanning electron microscopy (SEM), atomic force microscopy (AFM), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, contact angle (CA) and X-ray diffraction (XRD). The biological activity of plasma treated gelatin nanofibers were further investigated by using fibroblasts as cell models. SEM studies showed that the average diameter and the surface morphology of nanofibers did not change after plasma treatment. However, the mean surface roughness (RMS) of samples were increased due to plasma activation. ATR-FTIR spectroscopy demonstrated several new bands on plasma treated fibers related to the plasma ionization of nanofibers. The CA test results stated that the surface of nanofibers became completely hydrophilic after argon–oxygen plasma treatment. Finally, increasing the polarity of crosslinked gelatin after plasma treatment resulted in an increase of the number of fibroblast cells. Overall, results expressed that our developed method could open new insights into the application of the plasma process for functionalization of biomedical scaffolds. Moreover, the cooperative interplay between gelatin biomaterials and argon/argon–oxygen plasmas discovered a key composition showing promising biocompatibility towards biological cells. Therefore, we strongly recommend plasma surface modification of nanofiber scaffolds as a pretreatment process for tissue engineering applications.

Fabrication and characterization of TiO2 and MWCNT coated electrospinning nanofibers for UV protection properties

This paper aimed to fabricate UV protective nanofibers by the use of specific nanoparticles. The DMF/TiO2 (Titanium dioxide), DMF/MWCNT (Multi-Walled Carbon Nano Tubes), and DMF/MWCNT+TiO2 (MWCNT: TiO2 mass ratio= 1:1) solutions were transferred into a syringe with a stainless steel needle with gauge 21. The electrospinning process was performed for 3 h at the optimized conditions. The surface morphology of nanofibers was characterized by field emission scanning electron microscopy (FESEM). Fourier transform infrared spectroscopy (FTIR) was utilized to characterize functional groups of oxidized MWCNTs and investigate the successful load of nanoparticles at the fiber surface. The UV protection property of nanofibers was investigated by measuring UV rays' transmittance through the composite web. The data of Spectroscopy was used to compute the UV protection factor (UPF).(1) The effect of CNT,TiO2, and CNT+TiO2 nanoparticles on ultraviolet protection property was analyzed separately and simultaneously.(2) The different concentrations of nanoparticles, including 1,5,10, & 15 wt%, were used to fabricate UV protective nanocomposites.(3) The electrospinning condition was optimized as a 15 cm distance between the needle tip and collector, 20 KV voltage, 250 RPM drum rotation, and 1.2 ml/h feeding rate to access the best nanofibers.

Overcoming the potential drop in conducting polymer artificial muscles through metallization of electrospun nanofibers by electroplating process

Electrochemical actuators made of conducting polymers are one of the major types of artificial muscles that have attracted much attention in recent years. However, these artificial muscles suffer from potential drop along the length, which undermines their performance in applications requiring longer muscles. This study is aimed at enhancing the performance of this type of artificial muscles through overcoming the potential drop along the length. This is implemented using copper electroplating and creating a full-length highly conductive nanofibrous layer. Polyurethane/copper/polypyrrole (PU/Cu/PPy) nanofibrous artificial muscles were fabricated by combining electrospinning, electroplating and electrochemical polymerization. The copper electroplating affected many features of the PU nanofibrous layer including surface morphology of nanofibers, thermal, mechanical and electrical properties. Average diameter of the PU nanofibers was measured as 306 ± 48 nm, which increased significantly by increasing the duration of copper electroplating. By copper electroplating for 20 s, the onset temperature of nanofibers thermal decomposition was increased from 249 to 302 °C. Additionally, using this process, the sample Young’s modulus was increased from 2.20 ± 0.21 to 62.32 ± 5.42 MPa while its elongation at break was decreased from 173.84 ± 14.22 to 94.81 ± 10.96. After copper electroplating for duration as low as 20 s, the electrical conductivity of nanofibers was increased by more than 200 times from 48.90 ± 1.10 to 10 103.06 ± 14.28 S cm−1. Electrochemical polymerization of pyrrole on the surface of metalized nanofibers increased the average diameter of produced nanofibers to 1030 ± 102 nm. Providing an electrical connection along the entire length of artificial muscle resulted in enhanced electroactive property and hence final bending actuation of 88° for a cycle potential between −0.8 V and 0.5 V at a scan rate of 5 mV s−1 was observed. The nanofibrous artificial muscle fabricated by the proposed method has immense potential for use in practical applications.

Polymeric nanocomposite via electrospinning: Assessment of morphology, physical properties and applications

Polymeric nanofibers have appeared as unique one-dimensional nanomaterials. Nanofibers possess exceptionally high specific surface area and essential properties. Various polymeric nanofibers and nanocomposite nanofibers have been developed using thermoplastic and thermosetting matrices and organic and inorganic nanoparticles. This review documents the worth of nanofiber technology regarding the synthesis, morphology, physical properties, and applications of the nanostructures. The nanofiber surface morphology and diameter directly influence the physical characteristics such as electrical conductivity, mechanical properties, and thermal stability. Fiber processing techniques and related parameters also affect their texture and properties. In this regard, electrospinning is frequently used to form polymeric nanofibers and nanocomposite nanofibers. Electrospun nanofibers having large surface area and excellent fiber orientation, alignment, and morphology. The polymer nanocomposites with different nanofillers (carbon nanotube, graphene, carbon nanofibers, and other nanoparticles) have been processed into high performance electrospun nanofibers. Electrospun nanomaterials have been applied in engineered structures, nanofibrous membranes, electronic devices, tissue engineering, drug delivery, antibacterial materials and other biomedical applications. Henceforth, this is a comprehensive review on physical characteristics, morphology, processing aspects, and application areas for polymeric and nanocomposite nanofibers.

Synthesis of magnetic gold coated poly (ε-caprolactonediol) based polyurethane/poly(N-isopropylacrylamide)-grafted-chitosan core-shell nanofibers for controlled release of paclitaxel and 5-FU

The poly (ε-caprolactonediol) based polyurethane (PCL-Diol-b-PU)/poly(N-isopropylacrylamide)-grafted-chitosan (PNIPAAm-g-chitosan) core-shell nanofibers were synthesized via coaxial electrospinning process. Paclitaxel and 5-FU anticancer drugs were incorporated into the core of nanofibers. The nanofibers surface was coated using magnetic gold nanoparticles and the potential of synthesized nanofibers was investigated for the sustained release of paclitaxel and 5-FU toward 4T1 breast cancer cells death in vitro and in vivo. The synthesized magnetic nanoparticles were characterized using SEM, TEM, XRD and DLS analysis. The surface morphology of nanofibers was studied under various applied voltage and different shell flow rates. The paclitaxel and 5-FU release profiles from nanofibers were examined under acidic and physiological pH. The maximum 4T1 cell killing was found to be 78% using magnetic gold coated-nanofibers in the presence of external magnetic field. The SEM images after incubation of nanofibers in 4T1 breast cancer cells indicated the well adhesion of cells on the nanofibers surface. The in vivo studies showed that the tumor volume did not change during 10 days. The minimum increase in tumor volume was obtained using paclitaxel and 5-FU loaded-nanofibers coated by the magnetic gold nanoparticles. The obtained results demonstrated the high therapeutic efficiency of synthesized nanofibrous carrier toward breast cancer treatment.

A highly sensitive safrole sensor based on polyvinyl acetate (PVAc) nanofiber-coated QCM

A novel, highly sensitive and selective safrole sensor has been developed using quartz crystal microbalance (QCM) coated with polyvinyl acetate (PVAc) nanofibers. The nanofibers were collected on the QCM sensing surface using an electrospinning method with an average diameter ranging from 612 nm to 698 nm and relatively high Q–factors (rigid coating). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the PVAc nanofiber surface morphology, confirming its high surface area and roughness, which are beneficial in improving the sensor sensitivity compared to its thin-film counterpart. The as-spun PVAc nanofiber sensor could demonstrate a safrole limit of detection (LOD) of down to 0.7 ppm with a response time of 171 s and a sensitivity of 1.866 Hz/ppm. It also showed good reproducibility, rapid response time, and excellent recovery. Moreover, cross-interference of the QCM sensor response to non-target gases was investigated, yielding very low cross-sensitivity and high selectivity of the safrole sensor. Owing to its high robustness and low fabrication cost, this proposed sensing device is expected to be a promising alternative to classical instrumental analytical methods for monitoring safrole-based drug precursors.

Preparation and modification of forcespun polypropylene nanofibers for adsorption of uranium (VI) from simulated seawater

In this paper, polypropylene (PP) nanofibers were prepared using the melt forcespinning technology by a handmade device. Then, the surface of PP nanofibers was grafted through the high energy electron beams (EB) pre-irradiation method by acrylonitrile and methacrylic acid monomers with grafting percentage of 145.55%. The 92% of grafted cyano functional groups on nanofibers were converted to amidoxime groups, then modified by an alkaline solution. Characterization and surface morphology of nanofibers were investigated by Fourier Transform Infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The produced adsorbent was used to adsorb U(VI) ions from simulated seawater. The maximum adsorption was 83.24 mg/g in the optimal time of 60 min and optimal pH of 4. The optimum desorption efficiency was 80% in HCl 0.5 M. The kinetic data in optimum conditions showed that the adsorption followed an S-shaped kinetic model. The Adsorption equilibrium studies presented S-shape isotherm model that confirmed the adsorption occurs both on the adsorbent surface and in its pores The thermodynamic studies indicated spontaneous adsorption of uranyl ions and the higher efficiency adsorption at higher temperatures. The selectivity of adsorbent for metal ions followed the order V(V)>U(VI)>CO(II)>Ni(II)>Fe(II). These results shows that the prepared and modified nanofibers in this work can be considered as an effective and promising adsorbents for removal of uranium ions from seawater with high efficiency.

ELECTROSPUN CHITOSAN/PVA NANOFIBERS FOR DRUG DELIVERY

Electrospinning technique is a versatile method to fabricate continuous fibers with diameters ranging from a few micrometers to a few nanometers. In this study, chitosan/ poly (vinyl alcohol) (PVA) nanofibers were fabricated by an electrospinning method. The effects of chitosan molecular weights and ratio of chitosan/PVA were studied. The characteristics and surface morphologies of nanofibers were observed by the Scanning Electron Microscope (SEM). The diameters of nanofibers were in the range of 100 nm to 250 nm. The chitosan/PVA nanofibers with different molecular weights were applied for curcumin delivery. Curcumin was loaded in the chitosan/PVA nanofibers. Then, release profile of curcumin was investigated. In the results, the encapsulation efficiency and the release rate demonstrate that chitosan/PVA nanofibers would be potential carriers for curcumin and promise to create a prospective drug delivery in the field of medicine.

Effects of Dopant Types and Contents on Morphology and Strength Properties of PANI/PAN Electrospun Nanofibers

In this paper, the electrospinning of polyaniline under different dopant conditions were studied, the experimental phenomena was introduced, analyzed the relationship between the nanofiber surface morphology of DBSA-PANI/PAN, HCl-PANI/PAN and PTSA-PANI/PAN membranes and dopant type and content. The average diameter of DBSA-PANI/PAN electrospinning fiber membrane showed a decreasing trend when the content of doped polyaniline increased 1%-4%, and reached a minimum value of 780nm when the concentration was 4%. The strength of DBSA-PANI/PAN fiber membrane was the highest when the concentration of doped polyaniline was 1%, and the maximum intensity was 1.8×10 5 Pa. The average diameter of HCl/PANI/PAN fiber membranes decreases with the increase of doped polyaniline concentration, and it fluctuates up and down within a small range. When the content of doped polyaniline was increased to 4%, the average fiber diameter reached a minimum of 420 nm. The strength of the HCl-PANI/PAN fiber membrane was the highest when the concentration of doped polyaniline was 4%, and the maximum intensity was 1.08×10 5 Pa. The average diameter of the PTSA-PANI/PAN electrospun fiber membrane was the smallest at 2% doped polyaniline content and was 430 nm, the strength of PTSA-PANI/PAN fiber membrane is the highest when the content of doped polyaniline is 2%, and the maximum intensity is 3.9×10 4 Pa. In this paper, the basic research of doped polyaniline electrospinning nanofibers has made a useful supplement to the existing research of polyaniline nanofibers, and has a reference value for the application of polyaniline.

Effect of carbon nanofiber surface morphology on convective heat transfer from cylindrical surface: Synthesis, characterization and heat transfer measurement

In this work, heat transfer surface modification is made by layers of carbon nanofiber (CNF) on a 50 μm nickel wire using Thermal chemical vapor deposition process (TCVD). Three different CNF layer morphologies are made, at 500 °C, 600 °C and 700 °C, to investigate the influence of morphology on heat transfer performance characteristics. Experimental results show that a CNF layer made at 500 °C behaves like an additional heat resistance, which is attributed to the dense structure of the layer of fibers. This results in 25% lower heat transfer compared to the heat transfer performance of the bare wire. However, samples made at 600 °C, exhibit a relatively porous layer of CNFs with relatively lower thermal conductivity compared to samples made 500 °C, resulting in an enhancement of 24%. This is because the relative porous structure leads to relatively better flow permeability which reduces the thermal resistance of the layer. Samples made at 700 °C are partly covered with a dense CNFs layer and partly with an amorphous layer of carbon. Heat transfer enhancement of 34% is achieved which is attributed to the combined effect of the highly conductive layer, high effective heat transfer surface area and rough surface morphology.

Ultrasonic dyeing of cellulose nanofibers

Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

Development of PEO nanofibers having novel morphologies via distance positioning apparatus

In this study, PEO nanofibers with novel architectures were developed via newly designed distance positioning apparatus in order to feed polymer solution in a different way. The surface morphology and alignment of nanofibers were observed using a scanning electron microscope (SEM). SEM micrographs revealed that different morphologies could be obtained by changing feeding position. For the first time in the nanofibers literature; nanofibers were simultaneously collected on three different positions (collector plate, X-axis, and Y-axis) and surface morphology of these nanofibers was found to be different which is promising in terms of their potential regarding utilization of same nanofibrous mat for functional applications.