Superhydrophobic Mats of Polymer-Derived Ceramic Fibers (original) (raw)
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Engineering Ceramic Fiber Nanostructures Through Polymer-Mediated Electrospinning
Polymer-Engineered Nanostructures for Advanced Energy Applications, 2017
Electrospinning is increasingly used as a simple and straightforward technique to fabricate one-dimensional fibers from both organic and inorganic materials. These one-dimensional fibers with controlled sizes possess some unique features such as large surface area to volume ratio, high porosity, and low density. Compared to other conventional materials, these features make them attractive for applications such as energy harvesting, energy storage, super-hydrophobic membranes, and sensors. This chapter provides an overview on the synthesis of inorganic fibers through polymer-mediated electrospinning. Some of the common techniques employed by many researchers, such as solgel combined with electrospinning, emulsion electrospinning, and electrospinning combined with solid-gas reaction, to fabricate metal oxide fibers are discussed. In addition, techniques to fabricate ceramic and metal oxide fibers having different morphologies and hierarchical structures are described. Recent applications of electrospun metal oxide fibers are finally highlighted with a focus on filtration, sensors, photocatalysis, and energy.
Materials Letters, 2021
Silicon oxycarbide (SiOC) fibers with different sub-micron-scaled sizes were fabricated through a spinning-aid-free electrospinning/sol-gel method. By controlling the acidity of the sol-gel system, precursor solutions with different viscosities were prepared and directly used for electrospinning. The effects of pH value on the molecular configuration of sol-gel derived precursors have been analyzed by solid-state nuclear magnetic resonances (SSNMR) test. The influence of precursors' configuration on the morphology of resulted fibers has also been investigated. Polysiloxane (PSO) precursors derived from a mild acidity (pH = 4) presented the optimal crosslinked configuration and yielded the finest bead-free SiOC fibers with an average diameter of 257 ± 3 nm. This spinning-aid-free electrospinning/sol-gel method could be potentially adapted to other metal alkoxide systems to fabricate a broader range of ceramic fibers.
Electrospun Proficient Polymer Based Nano Fibers with Ceramic Particles
Journal of Superconductivity and Novel Magnetism, 2012
Cobaltite of magnesium, embedded in polyvinylpyrrolidone (PVP) polymeric fibers forming nanocomposite were synthesized by combining conventional sol-gel method with electrospinning method. Ultrathin diameter polymer fibers containing nanoregime ceramic particles were obtained by varying various process parameters like voltage, concentration, feed rate, distance between nozzle tip and base plate on an indigenously assembled electrospinning unit. Polyvinylpyrrolidone (PVP) and polyvinylalcohol (PVA) polymeric fibers in nanoregime were also synthesized separately and the effect of the process parameters was observed on the fiber thickness and continuity. Characterization was done to verify the synthesis parameter effect on structural morphology of polymer based nanofiber composite. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were used as tools for study of structural morphology and its correlation with process parameters.
Near superhydrophobic-fluorinated THV fiber-like structures and fibers prepared by electrospinning
High Performance Polymers, 2015
In the fluoropolymers family, one of the newest members is the terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride (THV). There are scarce data on THV, and therefore it is necessary to study different properties of THV. In the current research, the detailed surface morphology and water wettability of electrospun microfibers prepared from THV/ethyl acetate solutions in the pure state and with the addition of Wyoming-type low-magnesium montmorillonite are discussed. The morphology of the terpolymer microfibers changes as a function of the polymer solution concentration. For the same polymer concentration, changing the applied voltage in microfiber formation does not alter the morphology. The addition of hydrophilic montmorillonite into the THV solution does not modify the rougher hydrophobic nature and morphology of the final electrospun fiber surfaces. Water contact angle measurements show that both in the pure state and in the mixture of montmorillonite, THV electrospun microfibers exhibit ''near superhydrophobic'' characteristics with contact angles as high as 145 .
Synthesis of the Novel Type of Bimodal Ceramic Nanowires from Polymer and Composite Fibrous Mats
Nanomaterials, 2018
The purpose of this paper was to produce SiO 2 and TiO 2 nanowires via the electrospinning process from a polyvinylpyrrolidone (PVP)/Tetraethyl orthosilicate (TEOS)/Titanium (IV) butoxide (TNBT)/dimethylformamide (DMF) and ethanol (EtOH) solution. The as-obtained nanofibers were calcined at temperatures ranging from 400 • C to 600 • C in order to remove the organic phase. The one-dimensional ceramic nanostructures were studied using a scanning electron microscope (SEM) and a transmission electron microscope (TEM) to analyze the influence of the used temperature on the morphology and structures of the obtained ceramic nanomaterials. In order to examine the chemical structure of the nanowires, energy dispersive spectrometry (EDX) and Fourier-Transform Infrared spectroscopy (FTIR) were used. The optical property analysis was performed on the basis of UV-Vis spectra of absorbance as a function of the wavelength. Using the modified Swanepoel method, which the authors proposed and the recorded absorbance spectra allowed to determine the banded refractive index n, real n and imaginary k part of the refractive index as a function of the wavelength, complex dielectric permeability ε, and real and imaginary part ε r and ε i of the dielectric permeability as a function of the radiation energy of the produced ceramic nanowires.
Structure and Properties of Ceramic Fibers Prepared From Polymeric Precursors [1]
MRS Proceedings, 1986
Ceramics can be prepared by pyrolysis of organosilicon polymers. Advantages of this method of ceramics preparation are; the ability to prepare shapes difficult to achieve by other methods such as fibers and films; the ability to achieve high purity because reagents used to prepare the polymer can be purified by well established chemical methods; processing at lower temperature than conventional methods [211. This approach is being used to prepare ceramic fibers, which may be used for reinforcement of ceramic, metal and plastic matrices. The primary goal is development of a family of Si-C, Si-C-N and SiN fibers which can be used to fabricate ceramic composites with high fracture toughness, high temperature performance and ease of formation of complex shapes. Attainment of this goal would overcome the poor design reliability of existing ceramics due largely to catastrophic brittle failure. An integrated, multistep process scheme is used to prepare ceramic fibers. An organosilicon, thermoplastic polymer is synthesized, converted to a fiber by melt-spinning, crosslinked in the solid state to cured fiber, and pyrolyzed to 1100-1400 C in an inert atmosphere. This paper characterizes the chemical structure, microstructure, morphology and some properties of such ceramic fibers. Ceramic fibers which were characterized include a standard grade of
Polymer International, 2008
Superhydrophobic materials are currently used for their water‐repelling, self‐cleaning and anti‐fouling properties but are also potentially attractive to prevent snow or ice accumulation on exposed structures. Using the electrospinning technique, polymer mats made of polystyrene and poly[tetrafluoroethylene‐co‐(vinylidene fluoride)‐co‐propylene] (PTVFP) were prepared. They were found to show highly hydrophobic properties, water contact angle (CA) between 130 and 150°, when a dual fiber–bead microstructure was observed. Superhydrophobicity, CA > 150°, was reached when PTVFP mats were electrospun from a polymer solution containing dispersed polytetrafluoroethylene (PTFE) nanoparticles. Using atomic force microscopy imaging, protruding nanosized asperities on fiber and bead surfaces were observed and this structure led to superhydrophobic properties. Materials prepared from a high‐viscosity PTVFP/ethyl acetate solution with PTFE particles, 200 nm diameter and 8% (w/w), showed an 11....
ACS Sustainable Chemistry & Engineering, 2014
Solution blends of poly(L-lactic acid) (PLLA) and poly(3hyroxybutyrate-co-3-hydroxyvalerate) (PHBV) in chloroform/DMF were electrospun at room temperature on a stationary collection plate. Polymer blend ratio, PHBV hydroxyvalerate content, solvent ratio, polymer concentration, and electrospinning process parameters were varied to determine optimal electrospinning conditions. The success of each formulation at producing nonwoven mats of continuous submicron diameter fibers was evaluated by optical and scanning electron microscopy. The diameter of the blend fibers was larger than electrospun fibers of either neat electrospun polymer, with a higher PLLA ratio favoring a porous surface morphology and higher PHBV ratios favoring beaded fiber morphology. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to analyze the thermal properties of the fibrous mats. The glass transition temperatures of the fibers from blends decreased as the PHBV weight ratio increased. The crystallinity of the PHBV fraction decreased as the ratio of the polymer in the blend decreased, whereas the crystallinity of PLLA was unaffected by the blend ratio. Dynamic mechanical analysis (DMA) indicated that the tensile strength of electrospun PHBV was improved by blending. Porous PLLA/PHBV electrospun fibers have potential for applications that need a high surface to volume ratio such as filtration, biomedical, energy storage devices, etc.
MRS Proceedings, 2012
Considerable research has focused on the formation of superhydrophobic surfaces utilizing both the chemical composition of surfaces and geometric effects. In this study, a superhydrophobic polycarbonate (PC) network surface was produced from hydrophilic polycarbonate through electrospinning process. Complex surface geometries often related to material roughness is used to evaluate the wetting behavior of electrospun polycarbonate fiber network. The surface properties of electrospun polycarbonate fibers are therefore examined with the potential to exploit the fibers through enhancing hydrophobic behavior. Characterization and analysis of PC electrospun fiber and PC film surfaces were carried out to compare surface roughness with wetting contact angle. Analytical models are used to describe hydrophobicity in terms of roughness.
Fabrication of ceramic nanofibers using polydimethylsiloxane and polyacrylonitrile polymer blends
Journal of Applied Polymer Science, 2017
ABSTRACTNanofibers with several hundred of nanometers were successfully fabricated using electrospinning process and a mixture of two types of polymers which are: polydimethylsiloxane and polyacrylonitrile as precursors. After stabilization and carbonization at 1000 °C, three phases which are: silicon carbide (SiC), carbon, and oxy‐SiC were presented. Spectroscopic and microscopic techniques had confirmed the presence of nanocrystalline SiC and turbostratic carbons. These phases formed an intertwined network at the nanometric scale. In addition, the resulted fibers showed a core‐skin effect with skin richer in carbon and a core mainly dominated by silicon‐based phases in the form SiC or SiOC ceramics. A significant improvement was observed in both tensile strength and elastic modulus in these hybrid fibers. In term of crystallography, these nanofibers seem to exhibit similar microstructure that was observed in Nicalon fiber. However, it was difficult to determine the ratio of thes...