Polyvinyl Alcohol Molecules Research Articles

One-step preparation of woven fabric-reinforced hydrogel composite

Cotton-woven fabric-reinforced polyvinyl alcohol-based hydrogel composite was produced by constructing cotton as warp and polyvinyl alcohol/cotton hybrid and polyvinyl alcohol yarns as weft yarns in the fabric structure. As-prepared polyvinyl alcohol/cotton fabrics were treated with different concentrations of aqueous borax and glutaraldehyde crosslinking solutions. Polyvinyl alcohol molecules were transformed to crosslinked gel structure after the treatments. Since cotton yarns kept their yarn structure in the fabrics, woven fabric-reinforced hydrogel composites were obtained. Chemical analysis to investigate crosslinking was conducted by attenuated total reflection–Fourier transform infrared spectroscopy spectra analysis, and the results revealed that a proper crosslinking of polyvinyl alcohol molecules in polyvinyl alcohol yarns occurred by using both borax and glutaraldehyde as crosslinkers. Thermal stabilities of the samples were observed via thermogravimetric analysis measurements. Even though borax crosslinking increased the thermal stability, glutaraldehyde crosslinking did not have a significant effect on the thermal stability of hydrogel composite. Crystalline microstructural analysis was carried out with X-ray diffraction measurement. Tensile properties of the samples by focusing on the crosslinker ratio and water contents in the hydrogel composites were performed. The results revealed that tensile properties of hydrogel composite tremendously increased with fabric reinforcement. Also, breaking force gradually increased when the hydrogel composite structure released the water from its structure at both borax and glutaraldehyde samples. Since the produced fabric-reinforced hydrogel composites have high strength, they are promising candidates as hygroscopic materials for planting and erosion control at inclined terrains.

Microdrop-Assisted Microdomain Hydrophilicization of Superhydrophobic Surfaces for High-Efficiency Nucleation and Self-Removal of Condensate Microdrops.

Superhydrophobic-hydrophilic hybrid surfaces have attracted intensive interest because of their significant academic and commercial values. However, almost all reported microdomain hydrophilicization methods rely on costly micropatterning techniques that need special instruments. Here, we report a microdrop-assisted method for microdomain hydrophilicization of a low-adhesive superhydrophobic surface and demonstrate its utility in high-efficiency nucleation and self-removal of condensate microdrops. Micrometer-sized fogdrops containing polyvinyl alcohol molecules can be selectively captured by breath figures of superhydrophobic surfaces with specific sizes and spatial distributions and can be converted into desired hydrophilic microdomains after thermal evaporation. After exploring the influence of hydrophilic microdomains' distributions and sizes to surface wettability, adhesion, and condensation dynamics, we achieved an optimal hybrid surface, which possesses 240% average microdrop density, 387% microdrop self-removal rate, and 75% average microdrop diameter as compared to the contrast superhydrophobic surface with uniform chemistry nature. This method is dispensed with special equipment, easy to implement, very cheap, and eco-friendly, which would help develop other superhydrophobic-hydrophilic hybrid surfaces with different functions such as water harvesting, dehumidification, and heat exchange.

Molecular dynamics modeling of the structure, dynamics, energetics and mechanical properties of cement-polymer nanocomposite

Efforts to tune the performance of organic/inorganic composites are hindered owing to a lack of knowledge related to the interfacial interaction mechanisms. Here we investigated the interfacial structure, dynamics, energetics and mechanical properties between calcium silicate hydrates (C-S-H) and polymers by molecular dynamics (MD) simulation. In this work, polyethylene glycol (PEG), polyvinyl alcohol (PVA) and polyacrylic acid (PAA) are intercalated into nanometer channel of C-S-H sheets to construct the model of polymer/C-S-H composite. In the interfacial region, the calcium ions near the surface of C-S-H play mediating role in bridging the functional groups in the polymers and oxygen in the silicate chains by forming Os-Ca-Op bond. In addition to ionic bonding, the bridging oxygen (C-O-C) in the PEG, hydroxyl (C-OH) in the PVA and carboxyl groups (-COOH) in the PAA provide plenty oxygen sites to form H-bonds with silicate hydroxyl, interlayer water and calcium hydroxyl in C-S-H substrate. The interfacial binding energy is dependent on polarity of functional groups in the polymers, the stability of the H-bond and Ca-O bond, ranking in the following order: E(PAA)> E(PVA) > E(PEG). The PVA with small number of H-bonds formed between oxygen in PVA and water molecules, resulting in increasing the mobility of confined water in the interlayer region. On the other hand, PAA and PVA, with strong polarity, can provide more number of non-bridging oxygen sites that widely distributed along the polymer chains to associate with more calcium ions and H-bonds. Furthermore, uniaxial tensile test is utilized to study the mechanical behavior of the composites. The incorporation of polymers, strengthening the H-bonds in the interfacial region and healing the defective silicate chains, can inhibit the crack growth during the loading process, which both enhance the cohesive strength and ductility of the C-S-H gel. In particular, the intercalated PAA increases the Young's modulus, tensile strength and fracture strain of C-S-H gel to 22.27%, 19.2% and 66.7%, respectively. The toughening mechanism in this organic/inorganic system can provide useful guidelines for polymer selection, design, and fabrication of C-S-H/polymer nanocomposites, and help eliminate the brittleness of cement-based materials from the genetic level.

Preparation and adsorption mechanism of polyvinyl alcohol/graphene oxide‐sodium alginate nanocomposite hydrogel with high Pb(II) adsorption capacity

ABSTRACTA series of polyvinyl alcohol (PVA)/graphene oxide (GO)‐sodium alginate (SA) nanocomposite hydrogel beads were prepared through in situ crosslinking for Pb2+ removal. It was found that PVA and SA molecules were intercalated into GO layers through hydrogen bonding interactions, leading to the destruction of orderly structure of GO, while GO uniformly distributed in PVA matrix. With increasing PVA solution concentration, the hydrogel beads became more regular, a large number of polygonal pores with thin walls and open pores formed, the average pore size decreased, and the dense network structure formed. Meanwhile, the permeability of the composite hydrogel decreased, leading to the decline of Pb2+ adsorption capacity of the composite hydrogel. With increasing GO content, the ballability of the hydrogel beads was weakened, the pore size increased, and relatively loose network structure formed, resulting in an increase in permeability and Pb2+ adsorption capacity of the hydrogel, reaching up to 279.43 mg g−1. Moreover, the composite hydrogel presented relatively good reusability for Pb2+ removal. The adsorption mechanism was explored and showed that the adsorption system of the composite hydrogel belonged to the second‐order kinetic model and fitted Langmuir adsorption isotherm model for Pb2+ removal, which might be mono‐layer chemical adsorption. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47318.

PVA-PDMS-Stearic acid composite nanofibrous mats with improved mechanical behavior for selective filtering applications

In this work, we report a facile way to fabricate composite nanofibrous mats of polyvinyl alcohol (PVA), polydimethylsiloxane (PDMS), and stearic acid (SA) by employing the electrospinning-technique, with PDMS fraction ranging from 40w% to nearly 80w%. The results show that for a predetermined fraction of PVA and SA, incorporation of an optimal amount of PDMS is necessary for which the mats exhibit the best mechanical behavior. Beyond this optimal PDMS fraction, the mechanical properties of the composite mats deteriorate. This result has been attributed to the ability of the SA molecules to mediate binding between the PVA and PDMS long-chain molecules via van-der-Waals bonding. The morphological, structural, mechanical, and thermal characterizations respectively using SEM, XRD, DMA/tensile test, and DSC lend support to this explanation. By this method, it is possible to control the hydrophilicity/oleophilicity of the mats, and the mats show an excellent selective permeability to oil as compared to water and successfully filter water from a water-in-oil emulsion. Incorporation of SA not only serves to aid in electrospinning of a PDMS-rich nanofibrous mat with good mechanical strength and control over hydrophilicity/oleophilicity, but also has a potential use in fabricating sheets impregnated with phase change materials for thermal energy storage.

Magnetic nanofibrous materials based on CMC/PVA polymeric blends

In this paper, the synthesis of magnetic nanofibrous materials with a soft ferromagnetic response based on magnetite nanoparticles (SMON) loaded to aqueous carboxymethyl-cellulose (CMC)/polyvinyl-alcohol (PVA) polymeric blends is reported. The nanofibrous materials were obtained from the electrospinning of SMON-CMC/PVA blends with different SMON content, applying a constant tension of 15 kV. The synthesized samples were analyzed by transmission electron microscopy, scanning electron microscopy, attenuated total reflectance Fourier transform infrared, Raman and X-Ray photoelectron spectroscopy, as well as static magnetic measuring. Our experimental findings indicate that nanofibers’ diameter decreases as SMON content in the electrospun polymeric blends is increased, since these magnetic nanoparticles diminish the interactions between PVA and CMC molecules, which improves their spinnability. Moreover, the spatial distribution of SMON in the fibers provides to the synthesized nanofibrous materials a novel soft ferromagnetic response at room temperature. This phenomenon is attributed to the formation of nanoparticles’ aggregates that are discretely distributed in the nanofibers.

Synthesis and characterization of chain-extended and branched polyurethane copolymers as form stable phase change materials for solar thermal conversion storage

In this work, polyethylene glycol (PEG) based polyurethane copolymer was synthesized using linear chain extension and branching methods. In linear chain extension, multiple PEG molecules were linked using urethane bonds. In branching, polyvinyl alcohol (PVOH) backbone was grafted with PEG molecules as branches and cross-linked to other PVOH molecules. 4,4′-Diphenylmethane di-isocyanate (MDI) was used as both chain extender and cross-linker. The resulting copolymers were characterized for chemical composition, microscopic morphology, crystalloid structure and thermal properties. Based on the results from characterizations, a detailed discussion on the phase change mechanism in polyurethanes is presented. 1H NMR and FT-IR results confirmed the chain extension and branching. 1H NMR spectra displayed characteristic signal of the urethane. DSC results revealed solid-solid phase change behavior of copolymers with high latent heat. Crystalline nature of spherulite lamellae structures was verified by observing birefringence using POM microscope and XRD peaks. Polyurethane copolymers had maximum latent heat absorption capacity of 144.14 kJ kg−1 at melting temperature of 51 ℃ and had maximum heat release capacity of 117.5 kJ kg−1 at freezing temperature of 33 ℃. Polyurethane copolymers were thermally stable up to 200 ℃. Polyurethane copolymers satisfied all criteria for use as form stable solid-solid phase change material (SSPCM) in solar thermal conversion storage.

Porous electrospun Casein/PVA nanofibrous mat for its potential application as wound dressing material

Caseins are phosphoproteins found in milk. Compared with proteins and amino acids, casein contains not only amino acid residues but also large quantities of phosphate groups, providing more active sites. In this work, uniform nanofibrous mats were obtained from various blend ratios of casein and polyvinyl alcohol (PVA) solutions by electrospinning. With above aqueous solution, when the casein/PVA mass ratios were 50/50–20/80, electrospinning of nanofibres were possible. The effect of blend ratio, viscosity and applied voltage on morphological appearance and fibre size was studied. Scanning electron microscopy showed that the addition of PVA facilitated the formation beadless nanofibres whose diameter increased with casein concentration in the range between 80 and 300 nm. Fourier transform infrared spectroscopy and X-ray diffraction studies demonstrated intermolecular hydrogen bonding and changes in crystallinity between the molecules of casein and PVA. Thermal analysis using thermo gravimetric analyzer revealed thermal degradation temperature of nanofibrous mat. BET specific surface area and pore volume of casein/PVA nanofibrous mat was measured to be 52.0541 m2/gm and 0.090 cc/gm respectively. Electrospun casein/PVA nanofibrous mat mimicked the natural biomineralization of bone, demonstrating that, it can effectively improve the bioactivity and be useful for hydroxyapatite formation. Thrombin–antithrombin complex human in vitro ELISA assay for Hemostatic activity of casein/PVA nanofibrous mat demonstrated acceleration in hemostatic activity through higher level of thrombin generation and stable blood clot. Hemostatic activity, in vitro biodegradation in proteinase enzyme and swelling characteristics shows that casein/PVA electrospun mat can have potential biomedical application in wound dressing material.

Characterization of solution casting derived carbon nanotube reinforced poly(vinyl alcohol) thin films

Carbon nanotube (CNT) reinforced polyvinyl alcohol (PVA) composite thin films have been prepared by a solution casting process at room temperature using gum acacia as a surfactant. CNT contents in the composites were varied from 5 to 10% by weight to increase its electrical conductivity. Electrical properties, such as conductivity, capacitance, dielectric constant and loss tangent, of the composites were investigated. All the electrical properties were found to be improved with the incorporation of CNTs. The absorbance and transmittance of light were determined by UV–visible spectroscopy and from the transmittance data, band gaps were calculated. The smallest band gap, of 1.18 eV, was found for the 10% CNT containing composite while the 0% CNT containing composite had a band gap of 2.4 eV. Thermal properties of the films were characterized by a thermo mechanical analyzer. The experimental results revealed that the blended films exhibited higher stability and improved thermal properties, which suggests the occurrence of an interaction, detected by FTIR, among PVA, CNT and water molecules in the films. The mechanical properties, tensile strength, elongation at break and Young modulus, were found to be improved. Water absorption properties of the composites were found to decrease with the increase of CNT content. The lowest water uptake properties and highest thermal stability were demonstrated by 10% CNT containing film. All of the results indicated that the developed PVA/CNT composite might be promising for use in optoelectronic application.

Solid-state reaction synthesis for mixed-phase Eu3+-doped bismuth molybdate and its luminescence properties

A method for mixed-phase bismuth molybdate doped with Eu[Formula: see text] ions was developed by solid-state reaction assisting with polyvinyl alcohol (PVA). The results of powder X-ray diffraction showed a mixed-phase structure and the microscopical characterization technology revealed the formation process with the addition of PVA. As a structure inducer, the PVA molecules played a vital role in the formation of phase structure. The as-obtained Eu[Formula: see text]-doped bismuth molybdates were also characterized by using different spectroscopic techniques including FTIR and photoluminescence (PL). The results show that doping concentration, PVA addition and calcination temperature affect photoluminescence properties remarkably.

Spectroscopic analysis of CdCl2 doped PVA–PVP blend films

The changes in molecular chemical structure of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), caused by doping PVA–PVP blend with cadmium chloride (CdCl2), have been studied using ultraviolet–visible (UV-Vis) spectroscopy, Fourier transform Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The formation of cadmium nano-structures and microstructures in CdCl2-doped PVA–PVP blend has been visualized using scanning electron microscopy, in the range of doping levels varying from 0.5 up to 10.2 wt% (doping level in weight percentage). The incorporation of dopant in PVA–PVP blend is confirmed using energy dispersive X-ray spectroscopy. The optical absorbance (UV-Vis) spectra of PVA–PVP blend films doped with CdCl2 from 0.5 up to 2.2 wt%, showed a prominent absorption hump with peak at the wavelength 370 nm, in addition to other intermediate energy bands caused by the interactions of CdCl2 with molecules of PVA and PVP. The photo-luminescence (emission and fluorescence) spectra show significant quenching of fluorescence in CdCl2-doped PVA–PVP blend films. Analysis of FTIR and Raman spectra suggest the possible modes of interaction of cadmium ions (Cd2+) and chlorine ions (Cl−) with reactive functional groups (C–N, hydroxyl and carbonyl groups) of polymeric molecules in the blend. A reaction scheme for interaction of CdCl2 with PVA–PVP blend is proposed, on the basis of spectroscopic studies on these films.

A novel fabrication of PVA/Alginate-Bioglass electrospun for biomedical engineering application

Objecttive (s): Polyvinylalcohol (PVA) is among the most natural polymers which have interesting properties such as nontoxic nature, biodegradability and high resistance to bacterial attacks making it applicable for tissue scaffolds, protective clothing, and wound healing.Materials and Methods: In the current work, PVA and Na-Alginate nanocomposite scaffolds were prepared using the electrospinning (ELS) technique in an aqueous solution. Also, (5% and 10%) addition of bioglass (BG) ceramic to the nanocomposite scaffold were investigated. The blended nanofibres are characterized by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), also the bioactivity evaluation of nanocomposite scaffold performed in simulated body fluid (SBF) solutions.Results: The FTIR analysis indicated that PVA and Alginate may have H+ bonding interactions. The results revealed that with a higher amount of BG, a superior degradation as well as a higher chemical and biological stability could be obtained in the nanobiocomposite blend fibres. Furthermore, the blend nanofibre samples of 10% BG powders exhibit a significant improvement during bioactivity and mechanical testing.Conclusion: The increasing water-contact angle on the polymer surface with decreasing PVA and Alginate content indicated that the scaffold were more hydrophobic than were PVA molecules. Also, In addition, the average diameter of fibers in the sample with 10% BG have the highest porosity compared to the other scaffold samples.

Synthesis of cellulose-based double-network hydrogels demonstrating high strength, self-healing, and antibacterial properties

Novel antibacterial double-network (DN) hydrogels with superior mechanical and self-healing properties are developed via the UV-initiated copolymerization of polyacrylic acid (PAA)-grafted quaternized cellulose (QCE) and polyvinyl alcohol (PVA). The QCE functioned as an antibacterial agent, resulting in excellent antibacterial capability (antibacterial rate >93%). The hydrogels are thus protected from microbial attack in natural environments, prolonging their lifetime. The PVA functioned as a physical cross-linker, resulting in superior mechanical properties. At PVA and QCE contents of 8% and 1.5%, respectively, the strain and stress at break of hydrogel were 465.37% and 1.13MPa, respectively. The hydrogel maintained good self-healing properties owing to ionic bonding between the ferric ions and carboxylic groups, and hydrogen bonding between the PVA molecules. The hydrogel was responsive to pH; its water-holding ability could be controlled by changing the pH. The material is simply prepared and used. Hydrogels with such excellent properties could be applied in various biomedical fields.

Sol‐immobilized vs deposited‐precipitated Au nanoparticles supported on CeO2 for furfural oxidative esterification

AbstractBACKGROUNDThe non‐edible nature of lignocellulose makes this an important raw material for future biorefineries. This work concerns the oxidative esterification of furfural (a C5 compound) to alkyl furoates, which find applications in the fine chemical industry.RESULTSVery efficient Au/CeO2 catalysts for furfural oxidative esterification were prepared by deposition of gold colloids using polyvinyl alcohol as protective agent. The catalysts provided complete conversion and selectivity without the presence of a base. Sol‐immobilized catalysts displayed better catalytic performances than Au/CeO2 prepared by deposition–precipitation (74% conversion). It was proposed that polyvinyl alcohol molecules act not only as gold stabilizer, but they leave ceria support uncovered and available for catalysis. The reaction is extremely sensitive to temperature, but can be carried out at very low pressures. Sol‐immobilized catalysts do not require any preliminary calcination to be activated and can be recovered by simple filtration: no oxidation of the exhausted catalyst is required for at least six catalytic runs.CONCLUSIONThe new catalyst is active, selective, recyclable and suitable for an industrial chemistry application based on renewable resources. Furoate ester can be obtained with optimal yields by a greener process than is presently used. © 2017 Society of Chemical Industry

Microstructure evolution of polyvinyl alcohol aqueous solution solidated in two-dimensional direction

Porous polymers have received much attention in recent years because of their light quality,high strength,good permeability and easy-revisable.Various fabrication methods of porous polymers have been used in which ice templating is a process which can prepare porous materials with complex structures and fine microstructures.This method has been widely used to prepare porous polymers but it still has many problems,such as poor homogeneity of pore distribution and pore connectivity.To solve these problems,it is necessary to understand the morphology of ice crystal growth in the solidification process of polymer solution.In situ observation of directional solidification is adopted in this paper to study the morphology evolution during directional solidification of polyvinyl alcohol (PVA) aqueous solution with different concentrations and molecular weights under different pulling speeds.The experimental results show that the primary dendrite spacing of PVA aqueous solution decreases with the increase of pulling speed at low concentration (1 wt%,2.5 wt%).However,increasing PVA concentration does not result in significant change in primary dendrite spacing.The primary dendrite spacing varies with pulling speed whereas the dendritic primary arm tends to shrink with increasing velocity.The effects of PVA concentration and pulling speed on morphology are partly because of diffusion instability from the classical solidification theory.When the concentration of solution is 5 wt%,there is little change of primary dendrite spacing with the velocity,which is due to the suppressed diffusion instability by high concentration of the polymer solution and large viscosity.When the concentration of solution increases to 10 wt%,ice crystal morphology is seaweed-like,where the PVA molecules are enriched and crosslinked ahead the ice crystal,leading to the continuous bifurcation of the dendrites.For the solidification morphologies of the aqueous solutions with different PVA molecular weights,the primary dendrite spacing of PVA aqueous solution decreases with the increase of pulling speed at low molecular weight (Mw=24000).Increasing PVA molecular weight does not result in significant change in primary dendrite spacing.At the low PVA molecular weight,the interface shows cell morphology.With the increase of PVA molecular weight,the large chain length leads to the stronger interaction among them and suppressing their diffusion. The corresponding constitutional undercooling is strengthened,thereby promoting the interfacial instability and dendrite formation.From the classical solidification morphology formation mechanism it may be concluded that the solidification morphology of PVA aqueous solution is determined by the competition between the two different mechanisms,i.e., interface instability induced by diffusion of PVA molecule and the local phase separation from the crosslinking of PVA polymer chains.

Application of mesoscale simulation to explore the aggregate morphology of pH-sensitive nanoparticles used as the oral drug delivery carriers under different conditions

The pH-sensitive nanoparticles are selected as the potentially promising oral protein and peptide drug carriers due to their excellent performance. With the poly (lactic-co-glycolic acid)/hydroxypropyl methylcellulose phthalate (PLGA/HP55) nanoparticle as a model nanoparticle, the structure-property relationship of nanoparticles with different conditions is investigated by dissipative particle dynamics (DPD) simulations in our work. In the oral drug delivery system, the poly (lactic-co-glycolic acid) (PLGA) is hydrophobic polymer, hydroxypropyl methylcellulose phthalate (HP55) is pH-sensitive enteric polymer which used to protect the nanoparticles through the stomach and polyvinyl alcohol (PVA) is hydrophilic polymer as the stabilizer. It can be seen from DPD simulations that all polymer molecules form spherical core-shell nanoparticles with stabilizer PVA molecules adsorbed on the outer surface of the PLGA/HP55 matrix at certain compositions. The DPD simulation study can provide microscopic insight into the formation and morphological changes of pH-sensitive nanoparticles which is useful for the design of new materials for high-efficacy oral drug delivery.

Molecular interactions in solutions of poly vinyl alcohol : an ultrasonic study

Ultrasonic velocity, density, viscosity have been measured experimentally in the binary and ternary mixtures of Poly Vinyl Alcohol (PVA), water and borax with various concentration at 301.32 K. As the acoustical parameters like adiabatic compressibility, intermolecular free length, relaxation time, acoustic impedance, surface tension, Rao’s and Wada’s constant, ultrasonic attenuation and free volume would be more useful to predict and confirm the molecular interaction, these have been determined by using ultrasonic velocity, density and viscosity of the prepared solution. It has been identified that the molecular interactions in binary mixture were stronger than that of in ternary mixtures. And also there is a strong solute – solvent interaction occurring in both binary and ternary solutions. This may be due to the greater possibility of hydrogen bonding between PVA and Water molecules. When the borax is added, the molecular interaction is getting weaker due to greater affinity of borate ion towards the hydrogen in hydroxyl group of PVA.

Fabrication and Characterization of Poly(Vinyl Alcohol)/Chitosan Blend Electrospun Nanofibrous Membrane

In this study, poly (vinyl alcohol) / chitosan blend nanofibers were synthesized by electrospinning process in different polyvinyl alcohol and chitosan weight ratios. The nanofibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). SEM images showed that, 50:50 poly vinyl alcohol/chitosan blend was the ideal ratio for producing beadless nanofiber. The average diameter of the beadless nanofiber was found to be 123 nm. FTIR and XRD results demonstrated the presence of intermolecular hydrogen bonding between the molecules of poly vinyl alcohol and chitosan.

Effect of surface-active agent on morphology and properties of electrospun PVA nanofibres

After the addition of a surface-active agent, sodium dodecyl benzene sulfonate (SDBS), electrospun polyvinyl alcohol (PVA) nanofibres showed a significant enhancement in the mechanical properties, such as improved tensile strength and elongation at break. The improved crystallinity and strong intermolecular hydrogen bonds between the molecules of SDBS and PVA were the two main factors that improved the mechanical properties. In addition, a sharp decrease in surface tension of PVA solution with the addition of SDBS was observed, and the protruding droplet at the tip of needle diminished in the electrospinning process.

Fabrication and Characteristics of Chelidonium majus Extracts Embedded Electrospun PVA Nanofiber

The purpose of this study was to determine whether addition of polyvinyl alcohol (PVA) to Chelidonium majus distilled water and ethanol extract could produce hybrid nanofiber through electrospinning process. The electrospinning process used PVA concentration at 12 wt%, voltage of 10 kV, and a tip to collector distance of 15 ㎝. Total polyphenol and total flavonoid contents were measured in order to verify the antioxidant activity of Chelidonium majus extract. The morphology of Chelidonium majus/PVA nanofibers produced through electrospinning was confirmed through scanning electron microscope (SEM). Coupling between Chelidonium majus extract and PVA molecule was identified via fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) analysis. Total polyphenol contents of distilled water extract and ethanol extract were 38.4 ㎎/g and 60.58 ㎎/g, respectively. Total flavonoid contents of distilled water extract and ethanol extract were 14.88 ㎎/g and 52.82 ㎎/g, respectively. The diameter of the PVA nanofiber was about 250 ㎚. After Chelidonium majus extract was added, the diameter of nanofiber was increased to be over 400 ㎚. As the concentration of Chelidonium majus extract was increased, the diameter of Chelidonium majus/PVA nanofiberalso was also increased. Without beads and incomplete spinning forms, the nanofibers were evenly spun. Hydrogen bond between Chelidonium majus extract and PVA and subsequent reduction in the degree of crystallization, melting point, and thermal capacity were confirmed by FT-IR, XRD, and DSC analysis. These results demonstrated that nanofiber could be produced after molecular binding is completed.