scholarly journals The Role of the Fiber/Bead Hierarchical Microstructure on the Properties of PVDF Coatings Deposited by Electrospinning

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 464
Author(s):  
Adrián Vicente ◽  
Pedro J. Rivero ◽  
José F. Palacio ◽  
Rafael Rodríguez
Keyword(s):  
Corrosion Resistance ◽  
Vinylidene Fluoride ◽  
Fiber Composite ◽  
Electrospun Fiber ◽  
Operational Parameters ◽  
Experimental Conditions ◽  
Electrospinning Technique ◽  
Water Contact ◽  
Good Thermal Stability ◽  
Vis Spectroscopy

Among the various polymeric options employed for the deposition of electrospun coatings, poly(vinylidene fluoride) (PVDF) has been widely investigated thanks to its excellent mechanical properties, high chemical resistance, and good thermal stability. In this work, the electrospinning technique is used for the fabrication of functional PVDF fibers in order to identify and evaluate the influence of the experimental conditions on the nanofiber properties in terms of optical transmittance, wettability, corrosion resistance, and surface morphology. Some of these properties can play a relevant role in the prevention of ice formation in aircrafts. According to this, a matrix of 4 × 4 samples of aluminum alloy AA 6061T6 was successfully coated by controlling two operational input parameters such as the resultant applied voltage (from 10 up to 17.5 KV) and the flow rate (from 800 up to 1400 µL/h) for a fixed polymeric precursor concentration (15 wt.%). The experimental results have shown a multilevel fiber-bead structure where the formation of a fiber mesh directly depends on the selected operational parameters. Several microscopy and surface analysis techniques such as confocal microscopy (CM), field emission scanning electron microscopy (FE-SEM), UV/vis spectroscopy, and water contact angle (WCA) were carried out in order to corroborate the morphology, transmittance, and hydrophobicity of the electrospun fiber composite. Finally, the corrosion behavior was also evaluated by electrochemical tests (Tafel curves measurement), showing that the presence of electrospun PVDF fibers produces a relevant improvement in the resultant corrosion resistance of the coated aluminum alloys.

scholarly journals Modeling Experimental Parameters for the Fabrication of Multifunctional Surfaces Composed of Electrospun PCL/ZnO-NPs Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4312
Author(s):  
Pedro J. Rivero ◽  
Juan P. Fuertes ◽  
Adrián Vicente ◽  
Álvaro Mata ◽  
José F. Palacio ◽  
...  
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Surface Morphology ◽  
Water Contact Angle ◽  
Solution Concentration ◽  
Electrospun Fibers ◽  
Operational Parameters ◽  
Zno Nps ◽  
Electrospinning Technique ◽  
Water Contact

In this work, a one-step electrospinning technique has been implemented for the design and development of functional surfaces with a desired morphology in terms of wettability and corrosion resistance by using polycaprolactone (PCL) and zinc oxide nanoparticles (ZnO NPs). The surface morphology has been characterized by confocal microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (WCA), whereas the corrosion resistance has been evaluated by Tafel polarization curves. Strict control over the input operational parameters (applied voltage, feeding rate, distance tip to collector), PCL solution concentration and amount of ZnO NPs have been analyzed in depth by showing their key role in the final surface properties. With this goal in mind, a design of experiment (DoE) has been performed in order to evaluate the optimal coating morphology in terms of fiber diameter, surface roughness (Ra), water contact angle (WCA) and corrosion rate. It has been demonstrated that the solution concentration has a significant effect on the resultant electrospun structure obtained on the collector with the formation of beaded fibers with a higher WCA value in comparison with uniform bead-free fibers (dry polymer deposition or fiber-merging aspect). In addition, the presence of ZnO NPs distributed within the electrospun fibers also plays a key role in corrosion resistance, although it also leads to a decrease in the WCA. Finally, this is the first time that an exhaustive analysis by using DoE has been evaluated for PCL/ZnO electrospun fibers with the aim to optimize the surface morphology with the better performance in terms of corrosion resistance and wettability.

Novel Membrane Suitable for Membrane Distillation: Effect of Mixed Nanofillers on the Membrane Performance

2019 ◽  
Vol 801 ◽  
pp. 325-330 ◽  
Author(s):  
Mohamed R. El-Marghany ◽  
Ahmed H. El-Shazly ◽  
Mohamed Sameh Abdalghany Salem ◽  
Mohamed Nabil Sabry ◽  
Norhan Nady
Keyword(s):  
Sodium Chloride ◽  
Vinylidene Fluoride ◽  
Chloride Concentration ◽  
Membrane Distillation ◽  
Polymeric Membrane ◽  
Sodium Chloride Concentration ◽  
Electrospinning Technique ◽  
Average Pore ◽  
Water Contact ◽  
Membrane Performance

The aim of the present work is to investigate the performance of a newly fabricated membrane used for the membrane distillation process. Both titanium dioxide nanorods and multi-walled carbon nanotubes together were dispersed inside Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membrane. Both pure PVDF-HFP and its composite membrane with the two fillers together PVDF-HFP/TiO2-CNTs were fabricated using electrospinning technique and were imaged by using SEM. Both the fiber diameter and the average pore diameter were calculated by using ImageJ software. Static water contact angle, membrane porosity, liquid enter pressure were determined. Moreover, the membrane performance was determined by using membrane distillation (MD) system for desalination. The effect of the feed conditions such as feed temperature, flow rate, and salt concentration, were studied. The obtained results confirm the improvement in the membrane productivity up to 46% at 9000 ppm sodium chloride concentration and by about 13.7% than the pure polymeric membrane at the highest used feed sodium chloride concentration (36000 ppm).

scholarly journals Functionalized Electrospun Fibers for the Design of Novel Hydrophobic and Anticorrosive Surfaces

Coatings ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 300 ◽  
Author(s):  
Pedro Rivero ◽  
David Yurrita ◽  
Carlos Berlanga ◽  
José Palacio ◽  
Rafael Rodríguez
Keyword(s):  
Corrosion Resistance ◽  
Metal Oxide Nanoparticles ◽  
Chemical Vapor ◽  
Electrospinning Process ◽  
Electrospun Fibers ◽  
Electrospinning Technique ◽  
Water Contact ◽  
Force Microscopy ◽  
Hydrophobic Molecule ◽  
High Degree

In this work, a novel coating was deposited on aluminum alloy samples by using a combination of electrospinning and chemical vapor deposition (CVD-silanization) techniques in order to create a functionalized film with an enhancement of both corrosion resistance and hydrophobicity. The electrospinning technique makes the fabrication of highly crosslinked electrospun fibers possible by the combination of both poly(acrylic acid) and β-cyclodextrin, respectively, which can be easily functionalized in a further step by using the CVD-silanization process due to the evaporation of a hydrophobic molecule such as 1H,1H,2H,2H-Perflurodecyltriethoxysilane. In addition, the resultant electrospun fibers with a high degree of insolubility have been successfully fabricated and metal oxide nanoparticles (TiO2NPs) have been incorporated into the electrospun polymeric solution in order to improve the corrosion protection. The surface morphology has been determined by using light optical microscopy, atomic force microscopy, scanning electron microscopy, and water contact angle (WCA) measurements. The corrosion resistance has been evaluated by using both potentiodynamic polarization and pitting corrosion tests. Finally, the results related to WCA measurements after CVD-silanization corroborate that the surfaces have been successfully functionalized with a hydrophobic behavior in comparison with the electrospinning process, showing a considerable difference in the roughness.

scholarly journals DEVELOPMENT OF POLY (LACTIC-CO-GLYCOLIC ACID)/ BIOGLASS FIBERS USING AN ELECTROSPINNING TECHNIQUE

2018 ◽  
Vol 48 (2) ◽  
pp. 131-138 ◽  
Author(s):  
N. BRIZUELA GUERRA ◽  
D. CORREA FERRÁN ◽  
V. CALDAS DE SOUSA ◽  
J. A. DELGADO GARCÍA-MENOCAL ◽  
M. GARCÍA VALLÉS ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Glycolic Acid ◽  
Average Diameter ◽  
Sem Analysis ◽  
Operational Parameters ◽  
Fiber Morphology ◽  
Polymeric Fibers ◽  
Experimental Conditions ◽  
Electrospinning Technique ◽  
Calcium Phosphate Particles

This work establishes experimental conditions for the synthesis of polymeric fibers using the electrospinning technique, modifying some operational parameters such as drum collector rotation speed and applied voltage were modified. The samples were obtained from a copolymer of poly(lacticco-glycolic acid) (PLGA), with a molecular weight of approximately 220,000 g/mol, dissolved in a dimethyl sulfoxide/dichloromethane (3:1 v/v) solution. With the aim of developing scaffolds for bone tissue engineering, we added a calcium phosphate glass based on 44.5CaO-44.5P2O5-11Na2O to the fibrous PLGA structures. The preliminary characterization of these PLGA structures with and without the addition of biodegradable glass was performed using SEM analysis. We found the formation of aligned and homogeneous fibers with an average diameter of 5.2 ± 2.1 µm when using the 800 rpm - 8cm - 9 kV parameters. In addition, the incorporation of 1 wt.% of previously silanized calcium phosphate particles substantially altered the fiber morphology and porosity. However, a substantial increase in the bioactivity of the composite was observed in contrast with the unmodified PLGA.

scholarly journals Synthesis, Fabrication, and Characterization of Functionalized Polydiacetylene Containing Cellulose Nanofibrous Composites for Colorimetric Sensing of Organophosphate Compounds

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1869
Author(s):  
A K M Mashud Alam ◽  
Donovan Jenks ◽  
George A. Kraus ◽  
Chunhui Xiang
Keyword(s):  
Solid State ◽  
Hydroxyl Groups ◽  
Colorimetric Sensing ◽  
Electrospinning Technique ◽  
Hazardous Chemical ◽  
Tensile Tester ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Landmark Study

Organophosphate (OP) compounds, a family of highly hazardous chemical compounds included in nerve agents and pesticides, have been linked to more than 250,000 annual deaths connected to various chronic diseases. However, a solid-state sensing system that is able to be integrated into a clothing system is rare in the literature. This study aims to develop a nanofiber-based solid-state polymeric material as a soft sensor to detect OP compounds present in the environment. Esters of polydiacetylene were synthesized and incorporated into a cellulose acetate nanocomposite fibrous assembly developed with an electrospinning technique, which was then hydrolyzed to generate more hydroxyl groups for OP binding. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), Instron® tensile tester, contact angle analyzer, and UV–Vis spectroscopy were employed for characterizations. Upon hydrolysis, polydiacetylene esters in the cellulosic fiber matrix were found unaffected by hydrolysis treatment, which made the composites suitable for OP sensing. Furthermore, the nanofibrous (NF) composites exhibited tensile properties suitable to be used as a textile material. Finally, the NF composites exhibited colorimetric sensing of OP, which is visible to the naked eye. This research is a landmark study toward the development of OP sensing in a protective clothing system.

scholarly journals Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection Molding

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1039 ◽  
Author(s):  
Luciano Pisanu ◽  
Leonardo Costa Santiago ◽  
Josiane Dantas Viana Barbosa ◽  
Valter Estevão Beal ◽  
Marcio Luis Ferreira Nascimento
Keyword(s):  
Adhesive Strength ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Pure Shear ◽  
Central Area ◽  
Dissimilar Materials ◽  
Type I ◽  
Coconut Fiber ◽  
Adhesive Properties ◽  
Experimental Conditions

The growing demand in the consumer market for products with sustainable technologies has motivated new applications using overmolded natural fiber composites. Therefore, studies have been conducted mainly to understand the adhesive properties of overmolded parts. In the present study, a polypropylene (PP) composite with 30% coconut fibers without additives was developed with the aid of a corotating twin screw extruder. Subsequently, a multicomponent injection mold was developed based on the geometry of the ISO 527 type I specimen, in which samples overmolded with PP and PP–coconut-fiber composite, with the overlap in the central area, were obtained to evaluate the adhesive strength of dissimilar materials. The objective of this study was to evaluate the bond between PP and PP–coconut-fiber composite under different processing conditions using an adhesive strength testing device to perform a pure shear analysis. The experimental conditions followed a statistical design considering four factors in two levels and a significance level of 5%. The results indicated that adhesive strength increased significantly as the overlap area increased. It was observed that temperature and injection flow rate were the factors that most contributed to strengthening the bonds of dissimilar materials.

scholarly journals Investigations of ternary complexes of Co(II) and Ni(II) with thiodiacetate anion and 1,10-phenanthroline or 2,2’-bipyridine in aqueous solutions

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Dariusz Wyrzykowski ◽  
Joanna Pranczk ◽  
Dagmara Jacewicz ◽  
Aleksandra Tesmar ◽  
Bogusław Pilarski ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Substitution Reactions ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Hydroxo Complexes ◽  
Binary Complexes ◽  
Vis Spectroscopy ◽  
Potentiometric Titration Method ◽  
The Stability ◽  
Ph Range

AbstractA potentiometric titration method (PT) and a stopped-flow kinetic technique monitored by a UV−Vis spectroscopy have been used to characterize the stability of series of Co(II)- and Ni(II)-thiodiacetato complexes, M(TDA), in the presence of 1,10-phenanthroline (phen) or 2,2’-bipyridine (bipy) in aqueous solutions. The stability constants of the binary (1:1), ternary (1:1:1) as well as the resulting hydroxo complexes were evaluated and compared to the corresponding oxydiacetate complexes. Based on the species distribution as a function of pH the relative predominance of the species in the system over a pH range was discussed. Furthermore, the kinetic measurements of the substitution reactions of the aqua ligands to phen or bipy in the coordination sphere of the binary complexes M(TDA) were performed in the 288–303 K temperature range, at a constant concentration of phen or bipy and at seven different concentrations of the binary complexes (0.2–0.5 mM). The kinetic stability of the M(TDA) complexes was discussed in relation to the experimental conditions and the kind of the auxiliary ligands (phen/bipy). Moreover, the influence of the type of primary ligand (thiodiacetate/oxydiacetate) on the substitution rate of the auxiliary ligands was also compared.

Structure and Resistance to Electrochemical Corrosion of NiTi Alloy

2013 ◽  
Vol 203-204 ◽  
pp. 335-338 ◽  
Author(s):  
Bożena Łosiewicz ◽  
Magdalena Popczyk ◽  
Tomasz Goryczka ◽  
Józef Lelątko ◽  
Agnieszka Smołka ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Niti Alloy ◽  
Electrochemical Corrosion ◽  
High Resolution Electron Microscopy ◽  
Potential Method ◽  
Passive Layer ◽  
Open Circuit ◽  
Experimental Conditions ◽  
Electrochemical Tests ◽  
Reflectivity Method

The NiTi alloy (50.6 at.% Ni) passivated for 30 min at 130°C by autoclaving has been studied towards corrosion resistance in aqueous solutions of 3% NaCl, 0.1 M H2SO4, 1 M H2SO4 and HBSS. Structure and thickness of the passive layer (TiO2, rutile) were examined by X-ray reflectivity method and high resolution electron microscopy. Corrosion behavior of this oxide layer was investigated by open circuit potential method and polarization curves. It was found that the corrosion resistance of the passivated NiTi alloy is strongly dependent on the type of corrosive environment. The higher corrosion resistance of the tested samples was revealed in sulfate solutions as compared to chloride ones. The highest resistance to electrochemical corrosion of the NiTi alloy was observed in 0.1 M H2SO4 solution. Susceptibility to pitting corrosion of the tested samples was observed which increased with the concentration rise of chlorine anions in solution. Electrochemical tests for 316L stainless steel carried out under the same experimental conditions revealed a weaker corrosion resistance in all solutions as compared to the highly corrosion resistant NiTi alloy.

Degradation of Amaranth azo dye in water by heterogeneous photo-Fenton process using FeWO4 catalyst prepared by microwave irradiation

2015 ◽  
Vol 73 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Eric da Cruz Severo ◽  
Chayene Gonçalves Anchieta ◽  
Vitória Segabinazzi Foletto ◽  
Raquel Cristine Kuhn ◽  
Gabriela Carvalho Collazzo ◽  
...  
Keyword(s):  
Azo Dye ◽  
Fenton Reaction ◽  
Catalytic Properties ◽  
Interactive Effects ◽  
Fenton Process ◽  
Operational Parameters ◽  
Treatment Efficiency ◽  
Experimental Conditions ◽  
Decolorization Efficiency ◽  
Central Composite

FeWO4 particles were synthesized by a simple, rapid and facile microwave technique and their catalytic properties in heterogeneous photo-Fenton reaction were evaluated. This material was employed in the degradation of Amaranth azo dye. Individual and interactive effects of operational parameters such as pH, dye concentration and H2O2 dosage on the decolorization efficiency of Amaranth dye were evaluated by 23 central composite design. According to characterization techniques, a porous material and a well-crystallized phase of FeWO4 oxide were obtained. Regarding the photo-Fenton reaction assays, up to 97% color and 58% organic carbon removal were achieved in the best experimental conditions. In addition, the photo-Fenton process maintained treatment efficiency over five catalyst reuse cycles to indicate the durability of the FeWO4 catalyst. In summary, the results reveal that the synthesized FeWO4 material is a promising catalyst for wastewater treatment by heterogeneous photo-Fenton process.

scholarly journals PLA-Based Hybrid and Composite Electrospun Fibrous Scaffolds as Potential Materials for Tissue Engineering

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Anna Magiera ◽  
Jarosław Markowski ◽  
Elzbieta Menaszek ◽  
Jan Pilch ◽  
Stanislaw Blazewicz
Keyword(s):  
Tissue Engineering ◽  
Mechanical Tests ◽  
Hybrid Structures ◽  
Poly Lactic Acid ◽  
Electrospinning Technique ◽  
Water Contact ◽  
Human Osteoblasts ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Normal Human

The aim of the study was to manufacture poly(lactic acid)- (PLA-) based nanofibrous nonwovens that were modified using two types of modifiers, namely, gelatin- (GEL-) based nanofibres and carbon nanotubes (CNT). Hybrid nonwovens consisting of PLA and GEL nanofibres (PLA/GEL), as well as CNT-modified PLA nanofibres with GEL nanofibres (PLA + CNT/GEL), in the form of mats, were manufactured using concurrent-electrospinning technique (co-ES). The ability of such hybrid structures as potential scaffolds for tissue engineering was studied. Both types of hybrid samples and one-component PLA and CNTs-modified PLA mats were investigated using scanning electron microscopy (SEM), water contact angle measurements, and biological and mechanical tests. The morphology, microstructure, and selected properties of the materials were analyzed. Biocompatibility and bioactivity in contact with normal human osteoblasts (NHOst) were studied. The coelectrospun PLA and GEL nanofibres retained their structures in hybrid samples. Both types of hybrid nonwovens were not cytotoxic and showed better osteoinductivity in comparison to scaffolds made from pure PLA. These samples also showed significantly reduced hydrophobicity compared to one-component PLA nonwovens. The CNT-contained PLA nanofibres improved mechanical properties of hybrid samples and such a 3D system appears to be interesting for potential application as a tissue engineering scaffold.

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