scholarly journals Polarization of Electrospun PVDF Fiber Mats and Fiber Yarns

2021 ◽  
Author(s):  
Harshal Gade ◽  
Sreevalli Bokka ◽  
George G. Chase
Keyword(s):  
Polyvinylidene Fluoride ◽  
External Surface ◽  
Electrospinning Process ◽  
Electrospun Fibers ◽  
Fiber Mats ◽  
Surface Areas ◽  
Piezoelectric Polymers ◽  
Custom Made ◽  
Mass Ratios

Electrospun fibers are of interest in a number of applications due to their small size, simplicity of fabrication, and ease of modification of properties. Piezoelectric polymers such as Polyvinylidene Fluoride (PVDF) can be charged when formed in the electrospinning process. This chapter discusses fabrication of PVDF fiber mats and fiber yarns and the measurement of their charge using a custom-made Faraday bucket. The results show the measured charge per mass of fiber mats was greater than the values measured for the yarns of the same mass. The measured charges may be related to both mass and external surface areas of the mats and yarn samples. It was observed the area/mass ratios of the fiber yarns were more than 30% less than the fiber mats.

Poly(Lactic Acid) (PLA) Electrospun Fibers Containing Rice Extract: Release Characteristics and their Antioxidant Activity

2017 ◽  
Vol 757 ◽  
pp. 83-87 ◽  
Author(s):  
Piyachat Chuysinuan ◽  
Nitirat Chimnoi ◽  
Lalita Pattani ◽  
Panita Khlaychan ◽  
Patcharakamon Nooeaid ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Lactic Acid ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Fiber Surface ◽  
Electrospinning Process ◽  
Poly Lactic Acid ◽  
Electrospun Fibers ◽  
Fiber Mats ◽  
Negative Effect

This study aimed to fabricate electrospun poly(lactic acid) (PLA) fiber mats containing 3 kinds of rice extract (rice bran, riceberry and LeumPhum rice extracts) by using electrospinning. The rice extract has been reported to exhibit antioxidant activities. The neat and rice extract-loaded PLA fiber mats were smooth and no beads formed on the fiber surface with diameters ranging from 450-656 nm. Release characteristics of the rice extract-loaded electrospun PLA fiber mats were investigated using total immersion methods. The scavenging ability of LeumPhum rice extract-loaded electrospun fibers showed superior scavenging activity as determined using the DPPH radical scavenging method. The results suggested that rice extract incorporated in PLA nanofibers had no negative effect on antioxidant activity when using an electrospinning process.

ELECTROSPINNING OF BIOMATERIALS AND THEIR APPLICATIONS IN TISSUE ENGINEERING

Nano LIFE ◽  
2012 ◽  
Vol 02 (04) ◽  
pp. 1230010 ◽  
Author(s):  
JEN-CHIEH WU ◽  
H. PETER LORENZ
Keyword(s):  
Tissue Engineering ◽  
Electrospinning Process ◽  
Polymer Fibers ◽  
Nanometer Scale ◽  
High Porosity ◽  
Electrospinning Technique ◽  
Engineering Research ◽  
Fibrous Scaffolds ◽  
Surface Areas ◽  
Tissue Engineering Research

Electrospinning is a process for generating micrometer or nanometer scale polymer fibers with large surface areas and high porosity. For tissue engineering research, the electrospinning technique provides a quick way to fabricate fibrous scaffolds with dimensions comparable to the extracellular matrix (ECM). A variety of materials can be used in the electrospinning process, including natural biomaterials as well as synthetic polymers. The natural biomaterials have advantages such as excellent biocompatibility and biodegradability, which can be more suitable for making biomimic scaffolds. In the last two decades, there have been growing numbers of studies of biomaterial fibrous scaffolds using the electrospinning process. In this review, we will discuss biomaterials in the electrospinning process and their applications in tissue engineering.

scholarly journals Characterization of Tar Deposits, Extraction and Sorption Properties

2016 ◽  
Vol 62 (2) ◽  
pp. 1-4
Author(s):  
Adrian Pryszcz ◽  
Barbora Grycová ◽  
Ivan Koutník ◽  
Veronika Blahůšková
Keyword(s):  
Storage Tank ◽  
Potassium Hydroxide ◽  
Surface Characterization ◽  
External Surface ◽  
Single Point ◽  
Experimental Part ◽  
Surface Areas ◽  
Plot Analysis ◽  
Bet Method

Abstract The main goal of this paper was to characterize and find a useful solution for the decomposition of tar deposits. For the experimental part, tar deposits, formed by polymerization and condensation reactions, were chosen from a storage tank for tars. At first the initial analyses of tar deposits (elemental, thermogravimetric, and calorimetric analyses) were performed. After the characterization, the tar deposits were extracted in the Soxhlet extractor by acetone, toluene, and quinolone and activated with potassium hydroxide. As the final step of this work, the sorption characterization on the 3Flex Surface Characterization Analyzer (Micromeritics) was performed. The specific surface area of the samples was evaluated using two methods - a single point measurement at p/p0=0.2 and BET method. Micropore and external surface areas were calculated based on a t-plot analysis (carbon black model).

scholarly journals Electrospun Polyvinylidene Fluoride-Based Fibrous Scaffolds with Piezoelectric Characteristics for Bone and Neural Tissue Engineering

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 952 ◽  
Author(s):  
Li ◽  
Liao ◽  
Tjong
Keyword(s):  
Tissue Engineering ◽  
Polyvinylidene Fluoride ◽  
Neural Tissue ◽  
Electrospinning Process ◽  
Neural Cells ◽  
Neural Tissue Engineering ◽  
Engineering Applications ◽  
Pore Sizes ◽  
Β Phase ◽  
Small Pore

Polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE) with excellent piezoelectricity and good biocompatibility are attractive materials for making functional scaffolds for bone and neural tissue engineering applications. Electrospun PVDF and P(VDF-TrFE) scaffolds can produce electrical charges during mechanical deformation, which can provide necessary stimulation for repairing bone defects and damaged nerve cells. As such, these fibrous mats promote the adhesion, proliferation and differentiation of bone and neural cells on their surfaces. Furthermore, aligned PVDF and P(VDF-TrFE) fibrous mats can enhance neurite growth along the fiber orientation direction. These beneficial effects derive from the formation of electroactive, polar β-phase having piezoelectric properties. Polar β-phase can be induced in the PVDF fibers as a result of the polymer jet stretching and electrical poling during electrospinning. Moreover, the incorporation of TrFE monomer into PVDF can stabilize the β-phase without mechanical stretching or electrical poling. The main drawbacks of electrospinning process for making piezoelectric PVDF-based scaffolds are their small pore sizes and the use of highly toxic organic solvents. The small pore sizes prevent the infiltration of bone and neuronal cells into the scaffolds, leading to the formation of a single cell layer on the scaffold surfaces. Accordingly, modified electrospinning methods such as melt-electrospinning and near-field electrospinning have been explored by the researchers to tackle this issue. This article reviews recent development strategies, achievements and major challenges of electrospun PVDF and P(VDF-TrFE) scaffolds for tissue engineering applications.

Atterberg Limits as Indices of External Surface Areas of Soils

1983 ◽  
Vol 47 (5) ◽  
pp. 1054-1056 ◽  
Author(s):  
J. E. Hammel ◽  
M. E. Sumner ◽  
J. Burema
Keyword(s):  
External Surface ◽  
Atterberg Limits ◽  
Surface Areas

scholarly journals A Study of the Micropore Structure of Carbonized Rayon Yarn by Nitrogen Adsorption and Nonane Pre-Adsorption

1985 ◽  
Vol 2 (2) ◽  
pp. 89-95 ◽  
Author(s):  
J. N. Bohra ◽  
K. S. W. Sing
Keyword(s):  
External Surface ◽  
Nitrogen Adsorption ◽  
The Other ◽  
Adsorption Method ◽  
Micropore Structure ◽  
Surface Areas ◽  
Three Samples ◽  
Two Samples ◽  
Before And After ◽  
Gain Access

Adsorption isotherms of nitrogen have been determined at 77 K on three samples of carbonized rayon yarn, both before and after the pre-adsorption of n-nonane. In their original state the three samples were all highly microporous. Application of the αs-method of isotherm analysis reveals that their micropore volumes were 0·17–0·19 cm3g−1 and their external surface areas 20–27 m2g−1 (the corresponding BET areas being 427–483 m2g−1). Nonane pre-adsorption resulted in blockage of the entire micropore structure only in the case of one sample: micropore volumes ∼0·1 cm3g−1 were still available for nitrogen adsorption in the other two samples. It appears that nitrogen molecules were able to gain access to some parts of these micropore structures through wider pore entrances which were not completely blocked by the pre-adsorbed nonane. The work has shown that the nonane pre-adsorption method requires further investigation before it can be used with confidence for the assessment of microporosity.

scholarly journals Core-Shell Nanofibers of Polyvinylidene Fluoride-based Nanocomposites as Piezoelectric Nanogenerators

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2344
Author(s):  
Deepalekshmi Ponnamma ◽  
Mariem Mohammed Chamakh ◽  
Abdulrhman Mohmmed Alahzm ◽  
Nisa Salim ◽  
Nishar Hameed ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Wearable Electronics ◽  
Hybrid Nanocomposite ◽  
Mechanical Vibrations ◽  
Electrospinning Technique ◽  
Fiber Mats ◽  
Semiconducting Metal Oxides ◽  
Soft Electronics ◽  
Human Motions ◽  
Piezoelectric Nanogenerators

Flexible piezoelectric nanogenerators (PENG) are widely applied to harvest sustainable energy from multiple energy sources. The rational and simple design of PENG have great potential in soft electronics. Here we design a highly flexible PENG using the polyvinylidene fluoride (PVDF) and its copolymer, polyvinylidene hexafluoropropylene (PVDF-HFP) with two nanoarchitectures of semiconducting metal oxides, TiO2 and ZnO. The nanotubes of TiO2 and nanoflowers of ZnO are embedded in these different polymeric media by solvent mixing, and new fiber mats are generated by coaxial electrospinning technique. This process aligns the dipoles of polymers and nanomaterials, which is normally a pre-requisite for higher piezo potential. With excellent mechanical strength and flexibility, the tailored lightweight fiber mats are capable of producing good output voltage (a maximum of 14 V) during different mechanical vibrations at various frequencies and in response to human motions. The hybrid nanocomposite PENG is durable and inexpensive and has possible applications in wearable electronics.

Active Vibration Control of a Centrally Clamped Disc by Means of a Piezoelectric Polymer

1990 ◽  
Vol 204 (1) ◽  
pp. 43-51 ◽  
Author(s):  
J Irons ◽  
W Kennedy
Keyword(s):  
Vibration Control ◽  
Polyvinylidene Fluoride ◽  
Active Vibration Control ◽  
Flexible Structures ◽  
Bonding Layer ◽  
Piezoelectric Polymers ◽  
Piezoelectric Polymer ◽  
Steel Disc ◽  
Active Vibration ◽  
Theoretical Results

With the advent of piezoelectric polymers, it is now possible to implement distributed control of flexible structures. Previous investigations of piezoelectric active vibration control have been mainly concerned with beams and beam-like structures; here a thin, centrally clamped steel disc is considered with polyvinylidene fluoride (PVDF) acting as the control actuator. Assuming that the PVDF imparts a controlled moment, and having ascertained the coupling and bonding layer effects, theoretical results are obtained. These results are compared with experimental results.

Improvement of Morphology, Structure, and Thermal Properties of Electrospun PVA/RSF Fiber Mats by SiO2

2012 ◽  
Vol 184-185 ◽  
pp. 1017-1020 ◽  
Author(s):  
Yan Hua Liu ◽  
Li Xing Dai
Keyword(s):  
Thermal Properties ◽  
Silicon Dioxide ◽  
Solution Viscosity ◽  
Electrospun Fibers ◽  
Fiber Morphology ◽  
Fiber Mats ◽  
Hydrogen Bonding Interactions ◽  
Regenerated Silk Fibroin ◽  
Solution Conductivity ◽  
Scanning Electron

Poly(viny1 alcohol) (PVA)/regenerated silk fibroin (RSF)/silicon dioxide (SiO2) fiber mats were prepared by electrospinning of composite solutions. Fiber morphology was observed under a scanning electron microscope and effects addition of SiO2 was evaluated. Results showed that the obtained fibers exhibited a smooth outer surface, and the continuity was improved because of the different solution conductivity, solution viscosity and compatibility of PVA and RSF by the addition of 1.0 wt. % SiO2. It was found that both Si-O-C linkage and hydrogen bonding interactions were existed among SiO2, PVA, and RSF by FTIR spectroscopy. The addition of SiO2 also resulted in the decrease of crystallinity and increase of thermal properties of electrospun fibers, which were suggested as a result of enhanced compatibility and physical properties of PVA and RSF composite.

Enhanced magnetoelectric coupling and dielectric constant in flexible ternary composite electrospun fibers of PVDF-HFP loaded with nanoclay and NiFe2O4 nanoparticles

2020 ◽  
Vol 44 (26) ◽  
pp. 11356-11364
Author(s):  
Sobi K. Chacko ◽  
M. T. Rahul ◽  
B. Raneesh ◽  
Nandakumar Kalarikkal
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
Composite Fiber ◽  
Magnetoelectric Coupling ◽  
Electrospun Fibers ◽  
Fiber Mats ◽  
Ternary Composite ◽  
Magnetoelectric Properties ◽  
Nife2o4 Nanoparticles

Magnetoelectric flexible composite fiber mats with superior room temperature magnetoelectric properties.

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