scholarly journals Permeability of Electrospun Superhydrophobic Nanofiber Mats

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Sarfaraz U. Patel ◽  
Gabriel M. Manzo ◽  
Shagufta U. Patel ◽  
Prashant S. Kulkarni ◽  
George G. Chase
Keyword(s):  
Fiber Diameter ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Diameter Distribution ◽  
Fibrous Media ◽  
Water Contact ◽  
Fiber Mats ◽  
Nonwoven Fiber ◽  
Nanofiber Mats

This paper discusses the fabrication and characterization of electrospun nanofiber mats made up of poly(4-methyl-1-pentene) polymer. The polymer was electrospun in different weight concentrations. The mats were characterized by their basis weight, fiber diameter distribution, contact angles, contact angle hysteresis, and air permeability. All of the electrospun nonwoven fiber mats had water contact angles greater than 150 degrees making them superhydrophobic. The permeabilities of the mats were empirically fitted to the mat basis weight by a linear relation. The experimentally measured air permeabilities were significantly larger than the permeabilities predicted by the Kuwabara model for fibrous media.

scholarly journals A Sulfur Copolymers (SDIB)/Polybenzoxazines (PBz) Polymer Blend for Electrospinning of Nanofibers

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1526 ◽  
Author(s):  
Ronaldo P. Parreño ◽  
Ying-Ling Liu ◽  
Arnel B. Beltran
Keyword(s):  
Polymer Blend ◽  
Single Phase ◽  
Fiber Diameter ◽  
Electrospinning Process ◽  
Diameter Distribution ◽  
Sem Images ◽  
Water Contact ◽  
Fixed Concentration ◽  
New Material ◽  
Nanofiber Mats

This study demonstrated the processability of sulfur copolymers (SDIB) into polymer blend with polybenzoxazines (PBz) and their compatibility with the electrospinning process. Synthesis of SDIB was conducted via inverse vulcanization using elemental sulfur (S8). Polymer blends produced by simply mixing with varying concentration of SDIB (5 and 10 wt%) and fixed concentration of PBz (10 wt%) exhibited homogeneity and a single-phase structure capable of forming nanofibers. Nanofiber mats were characterized to determine the blending effect on the microstructure and final properties. Fiber diameter increased and exhibited non-uniform, broader fiber diameter distribution with increased SDIB. Microstructures of mats based on SEM images showed the occurrence of partial aggregation and conglutination with each fiber. Incorporation of SDIB were confirmed from EDX which was in agreement with the amount of SDIB relative to the sulfur peak in the spectra. Spectroscopy further confirmed that SDIB did not affect the chemistry of PBz but the presence of special interaction benefited miscibility. Two distinct glass transition temperatures of 97 °C and 280 °C indicated that new material was produced from the blend while the water contact angle of the fibers was reduced from 130° to 82° which became quite hydrophilic. Blending of SDIB with component polymer proved that its processability can be further explored for optimal spinnability of nanofibers for desired applications.

PREPARATION AND CHARACTERIZATION OF SUPER-HYDROPHOBIC SURFACES ON ALUMINUM AND STAINLESS STEEL SUBSTRATES

2010 ◽  
Vol 17 (03) ◽  
pp. 375-381 ◽  
Author(s):  
ZHIJIA YU ◽  
YUEFEI YU ◽  
YANFENG LI ◽  
SHANPENG SONG ◽  
SUBIN HUO ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Steel Substrate ◽  
Contact Angle Hysteresis ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Water Contact ◽  
New Feature ◽  
Steel Substrates ◽  
Aluminum Surfaces

Hierarchical alveolate structures in nano- to microscale were fabricated on both aluminum and stainless steel substrates via a chemical etching. On aluminum surfaces, sharp edged caves and plateaus were found. On stainless steel substrate, fine papillae stand on protuberances. These surfaces exhibit super-hydrophobic properties after the fluorination treatment, their water contact angles are 158° and 160°, respectively, with the contact angle hysteresis of about 5°. The roll off angle is about 5°. Ice melting behaviors on a plate of aluminum super-hydrophobic surface were compared with those on a hydrophilic one, their difference shows that the new feature of super-hydrophobic surface could be expected.

Fabrication and Characterization of Ultra Water Repellent Surfaces on Aluminum Alloy Substrate

2016 ◽  
Vol 705 ◽  
pp. 278-282
Author(s):  
Ri Han Chi ◽  
Yue Fei Yu ◽  
Zhi Jia Yu ◽  
Guo Zhu Kuang
Keyword(s):  
Aluminum Alloy ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Water Repellent ◽  
Water Contact ◽  
Hierarchical Roughness ◽  
Silane Coating ◽  
Coating Method ◽  
Sinusoidal Flow

The fabrication of metallic ultra water repellent surfaces is of great significance to many industrial and scientific areas. Ultra water repellent surfaces on aluminum alloy substrates were fabricated with acidic etching and fluoroalkyl silane coating method. The prepared surfaces exhibit good water repellent behaviors with water contact angles (WCA) larger than 150° and contact angle hysteresis (CAH) about 5°. The resultant surfaces were examined using scanning electron microscope (SEM). The results show that a kind of hierarchical roughness in micro-nanoscale is formed, which plays a key role for the fabrication of ultra water repellent surfaces. Fancy phenomena such as "chair-shaped flow", "flow orientation" and "sinusoidal flow" were observed when water flowed in a rectangular conduit constructed with one ultra water repellent wall and one super hydrophilic wall on the opposite side. The observations reveal some characteristics of water flow in ultra water repellent conduits.

scholarly journals Wetting behaviors of fluoroterpolymer fiber films

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 393-410
Author(s):  
Salim Ok ◽  
Julia Sheets ◽  
Susan Welch ◽  
Tingting Liu ◽  
Savas Kaya ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Vinylidene Fluoride ◽  
Fiber Diameter ◽  
Contact Angles ◽  
Diameter Distribution ◽  
Electrospun Fibers ◽  
Fiber Morphology ◽  
Water Contact ◽  
Fiber Diameter Distribution ◽  
Wetting Behaviors

AbstractVarious aspects of electrospun fibers prepared from terpolymer of tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (VDF) (THV)/acetone solutions at two applied voltages, THV/acetone solutions having Texas montmorillonite with two ratios, and THV/ethyl acetate solutions using two needle sizes are described. Fibers from THV/acetone and THV/ethyl acetate solutions showed shallow indentations and pores, respectively. The clay, functioning as electrospinning agent, did not influence the fiber morphology, but yielded narrower fiber diameter distribution and the thinnest fibers. Heterogeneous fiber diameter distribution and increase in the fiber diameters were observed by lowering the voltage for fibers of THV/acetone solutions. Fibers from THV/ethyl acetate solutions had the largest diameter and the broadest diameter distribution. Electrospun THV fibers having both hydrophobic characteristics with nearly 140° water contact angles and oleophilic properties with oil contact angles less than 45° might have applications in areas such as water/oil separation.

Development of superamphiphobic alumina nanofiber mats using trimethoxysilane with a short perfluoroalkyl chain

2017 ◽  
Vol 88 (16) ◽  
pp. 1803-1811 ◽  
Author(s):  
Shuya Gao ◽  
Koji Nakane ◽  
Akiyoshi Ohgoshi ◽  
Tadayuki Isaji ◽  
Masaaki Ozawa
Keyword(s):  
Contact Angle ◽  
Fiber Diameter ◽  
Contact Angle Hysteresis ◽  
Average Fiber Diameter ◽  
Water Contact ◽  
Alumina Nanofibers ◽  
Fiber Spacing ◽  
High Roughness ◽  
Nanofiber Mats ◽  
Long Chain

To avoid the generation of hazardous, long-chain perfluoroalkyl carboxylic acids (C nF2 n+1COOH, n ≥ 7), we develop relatively safer superamphiphobic alumina nanofiber mats. Our fabrication process focuses on two principles: lowering the surface energy using trimethoxy(1H, 1H, 2H, 2H-nonafluorohexyl)silane (C4F9CH2CH2Si(OCH3)3), which has short-chain perfluoroalkyls that are relatively safer than long-chain ones; and creating a high-roughness surface from electrospun alumina nanofibers with an average fiber diameter of 155 nm and inter-fiber spacing of 451 nm. Such mats exhibit super-repellency for water (contact angle [Formula: see text] = 157°, contact angle hysteresis [Formula: see text], advancing angle [Formula: see text] 158°, receding angle [Formula: see text] 156°), and n-hexadecane ([Formula: see text] = 151°, [Formula: see text]9°, [Formula: see text] 152°, [Formula: see text] 143°). Furthermore, superamphiphobicity is maintained up to 350℃.

scholarly journals Fabrication and Characterization of Lignin/Dendrimer Electrospun Blended Fiber Mats

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 518
Author(s):  
Somaye Akbari ◽  
Addie Bahi ◽  
Ali Farahani ◽  
Abbas S. Milani ◽  
Frank Ko
Keyword(s):  
Thermal Characteristics ◽  
Dendritic Polymers ◽  
Amino Groups ◽  
Fiber Mats ◽  
Potential Applications ◽  
Solution Electrospinning ◽  
Nanofiber Mats ◽  
Softwood Kraft Lignin ◽  
First Time

Blending lignin as the second most abundant polymer in Nature with nanostructured compounds such as dendritic polymers can not only add value to lignin, but also increase its application in various fields. In this study, softwood Kraft lignin/polyamidoamine dendritic polymer (PAMAM) blends were fabricated by the solution electrospinning to produce bead-free nanofiber mats for the first time. The mats were characterized through scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, zeta potential, and thermogravimetry analyses. The chemical intermolecular interactions between the lignin functional groups and abundant amino groups in the PAMAM were verified by FTIR and viscosity measurements. These interactions proved to enhance the mechanical and thermal characteristics of the lignin/PAMAM mats, suggesting their potential applications e.g. in membranes, filtration, controlled release drug delivery, among others.

scholarly journals AACVD Synthesis and Characterization of Iron and Copper Oxides Modified ZnO Structured Films

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 471 ◽  
Author(s):  
Martha Claros ◽  
Milena Setka ◽  
Yecid P. Jimenez ◽  
Stella Vallejos
Keyword(s):  
Contact Angle ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Contact Angles ◽  
Copper Oxides ◽  
Water Contact ◽  
X Ray ◽  
Hydrophobic Behavior

Non-modified (ZnO) and modified (Fe2O3@ZnO and CuO@ZnO) structured films are deposited via aerosol assisted chemical vapor deposition. The surface modification of ZnO with iron or copper oxides is achieved in a second aerosol assisted chemical vapor deposition step and the characterization of morphology, structure, and surface of these new structured films is discussed. X-ray photoelectron spectrometry and X-ray diffraction corroborate the formation of ZnO, Fe2O3, and CuO and the electron microscopy images show the morphological and crystalline characteristics of these structured films. Static water contact angle measurements for these structured films indicate hydrophobic behavior with the modified structures showing higher contact angles compared to the non-modified films. Overall, results show that the modification of ZnO with iron or copper oxides enhances the hydrophobic behavior of the surface, increasing the contact angle of the water drops at the non-modified ZnO structures from 122° to 135° and 145° for Fe2O3@ZnO and CuO@ZnO, respectively. This is attributed to the different surface properties of the films including the morphology and chemical composition.

Synthesis and characterization of novel polysiloxane-grafted fluoropolymers

2005 ◽  
Vol 83 (6-7) ◽  
pp. 553-558 ◽  
Author(s):  
Bilal Baradie ◽  
Patricia HM Lai ◽  
Molly S Shoichet
Keyword(s):  
Carbon Dioxide ◽  
Thermal Stability ◽  
Supercritical Carbon Dioxide ◽  
Vinyl Acetate ◽  
Vinyl Alcohol ◽  
Contact Angles ◽  
Synthesis And Characterization ◽  
Water Contact ◽  
Degradation Temperature

Fluorosilicone polymers combine the properties of both fluorocarbons and siloxanes, yielding materials with unique properties. Novel crosslinked fluorosilicone polymers were synthesized by grafting diisocyanate-terminated polydimethylsiloxane (PDMS) to hydroxyl-functionalized fluoropolymers of poly(tetrafluoroethylene-co-vinyl acetate-co-vinyl alcohol) (PTFE-VAc-VA), as confirmed by elemental bulk and surface analysis. The fluorosilicone polymers containing 34 mol% of TFE were thermally stable with a degradation temperature of 267 °C. Fluorosilicone films were found to be more hydrophobic than the parent, non-grafted fluoropolymers; dynamic advancing and receding water contact angles for PTFE-co-VAc-co-VA-g-PDMS were 104° ± 1° and 61° ± 1°, respectively, whereas for PTFE-co-VAc they were 90° ± 2° and 59° ± 2°. The combined properties of thermal stability and hydrophobicity suggest that these fluorosilicones may be useful for coating and paint applications.Key words: fluoropolymers, fluorosilicone, polydimethylsiloxane, supercritical carbon dioxide.

scholarly journals Characterization of Rough PTFE Surfaces by the Modified Wilhelmy Balance Technique

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1528
Author(s):  
Christian W. Karl ◽  
Andrey E. Krauklis ◽  
Andrej Lang ◽  
Ulrich Giese
Keyword(s):  
Fractal Dimension ◽  
Sessile Drop ◽  
Contact Angle Hysteresis ◽  
Contact Angles ◽  
Polymer Surfaces ◽  
Counting Method ◽  
Balance Technique ◽  
Receding Contact ◽  
The Mean

The wetting of rough polymer surfaces is of great importance for many technical applications. In this paper, we demonstrate the relationship between the mean roughness values and the fractal dimension of rough and self-affine PTFE surfaces. We have used white light interferometry measurements to obtain information about the complex topography of the technical surfaces having different height distributions. Two different methods for the calculation of the fractal dimension were used: The height difference correlation function (HDC) and the cube counting method. It was demonstrated that the mean roughness value (Ra) correlates better with the fractal dimension Df determined by the cube counting method than with the Df values obtained from HDC calculations. However, the HDC values show a stronger dependency by changing the surface roughness. The advancing and receding contact angles as well as the contact angle hysteresis of PTFE samples of different roughness were studied by the modified Wilhelmy balance technique using deionized water as a liquid. The modified Wilhelmy balance technique enables the possibility for future analysis of very rough PTFE surfaces which are difficult to investigate with the sessile drop method.

Preparation and characterization of phenolphthalein polyethersulfone/silica nanofibrous membranes by solution blowing

2018 ◽  
Vol 32 (6) ◽  
pp. 746-760 ◽  
Author(s):  
Guocheng Song ◽  
Yang Chen ◽  
Jing Zhu ◽  
Junrong Yu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Pure Water ◽  
Composite Membranes ◽  
Contact Angles ◽  
Attenuated Total Reflectance ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Water Contact ◽  
Solution Blowing ◽  
Nanofibrous Membranes

Phenolphthalein polyethersulfone (PES-C)/silica (SiO2) composite nanofibrous membranes were prepared via solution blowing. The spinning solutions were prepared by mixing a solution of PES-C in dimethylacetamide with different amounts of colloidal SiO2 in ethylene glycol. Attenuated total reflectance–Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, and water contact angles were conducted to characterize the properties of composite nanofibrous membranes. The results showed that the thermal properties and surface wettability were improved by the addition of appropriate amount of nano-SiO2. Furthermore, permeation fluxes of pure water and the filtration of starch suspension were measured to evaluate the antifouling property of the PES-C/SiO2 composite membranes.

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