Influence of Super Hydrophobic Modification on Protective Performance of PTFE Micropore Membrane

2012 ◽  
Vol 627 ◽  
pp. 726-729
Author(s):  
Xin Min Hao ◽  
Yuan Yang ◽  
Xin Xing Feng ◽  
Fei Wang
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Surface Modification ◽  
Protective Property ◽  
Membrane Surface ◽  
Mustard Gas ◽  
Hydrophobic Modification ◽  
Protective Material ◽  
Surface Expansion ◽  
Protective Performance

Using self - prepared fluorochemical surfactant, PTFE micropore membrane was modified to improve its hydrophobicity. The surface morphology of the membrane was observed by SEM and its Contact angle was determined by. The protective property of the membranes against mustard gas was evaluated using the break-through test. The result shows that, the thesis put forward a novel BC protection idea that through membrane surface modification the poisonous agent can be rolled into liquid spheres and slided away from the membrane surface automatically because of the low surface tension of the membrane, which stands out from the traditional methodology by quick poisonous agent surface expansion and evaporation on the surface of the BC protective material.

scholarly journals Surface Modification To Alleviate PVDF Membrane Fouling During Milk Protein Microfiltration

2021 ◽  
Author(s):  
Diba Mirriahi
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Mechanical Strength ◽  
Membrane Fouling ◽  
Polyvinylidene Fluoride ◽  
High Efficiency ◽  
Serum Proteins ◽  
Membrane Surface ◽  
Pvdf Membrane ◽  
Aqueous Treatment

The interest in using polyvinylidene fluoride (PVDF) membrane in order to separate casein and serum proteins has been raised due to its significant stability. However, the high hydrophobicity of PVDF membrane causes severe fouling during filtration processes. Ozonation, a surface modification process in which polar groups would be formed on the membrane surface, is widely known for its high efficiency. In the present study, the main objective was to optimize the ozonation parameters to reach the minimum fouling while the maximum mechanical strength could be retained. The contact angle of a water droplet on the membrane surface decreased from 73.5° to 50.4° after the treatment of the membrane at the optimal gaseous phase ozonation. This indicates an increase in the hydrophilicity of the treated membrane. Also, filtration performance demonstrated a lower fouling occurrence on the treated membrane as compared to the untreated one. Although gaseous ozonation yielded a slightly better performance in comparison to the aqueous treatment, the membrane treated with aqueous phase ozonation was benefited from conserving its mechanical strength. Activated carbon helped decreasing the contact angle and fouling as compared to the non-catalytic aqueous treatment while the tensile strength was not affected

Study of the Hydrophobic Modification of Chromium Sesquioxide with Lauric Acid

2012 ◽  
Vol 535-537 ◽  
pp. 1586-1590
Author(s):  
Shuang Luo ◽  
Ji Chuan Huo ◽  
Hong Lei ◽  
Jun Deng
Keyword(s):  
Crystal Structure ◽  
Contact Angle ◽  
Particle Size ◽  
Surface Modification ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Lauric Acid ◽  
Technical Condition ◽  
Hydrophobic Modification ◽  
Ft Ir

The surface modification of chromium sesquioxide with lauric acid was investigated, and the optimum technical condition was obtained according to the activation indexes of products, i.e. 1% of modifier in weight，70°C in temperature and 40 minutes in time. Contact angle, FT-IR, XRD and particle size distribution were conducted on both unmodified and modified chromium sesquioxide. The results indicate that lauric acid molecules are adsorbed on the surface of chromium sesquioxide chemically and new bonds formed. The surface modification does not destroy the crystal structure of chromium sesquioxide even though the particle size of chromium sesquioxide is reduced from 4.01μm to 2.71μm. The contact angle of the modified chromium sesquioxide with water is 143 °, which indicates that the surface of the chromium sesquioxide changes from hydrophilic to hydrophobic.

scholarly journals Surface Modification To Alleviate PVDF Membrane Fouling During Milk Protein Microfiltration

2021 ◽  
Author(s):  
Diba Mirriahi
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Mechanical Strength ◽  
Membrane Fouling ◽  
Polyvinylidene Fluoride ◽  
High Efficiency ◽  
Serum Proteins ◽  
Membrane Surface ◽  
Pvdf Membrane ◽  
Aqueous Treatment

The interest in using polyvinylidene fluoride (PVDF) membrane in order to separate casein and serum proteins has been raised due to its significant stability. However, the high hydrophobicity of PVDF membrane causes severe fouling during filtration processes. Ozonation, a surface modification process in which polar groups would be formed on the membrane surface, is widely known for its high efficiency. In the present study, the main objective was to optimize the ozonation parameters to reach the minimum fouling while the maximum mechanical strength could be retained. The contact angle of a water droplet on the membrane surface decreased from 73.5° to 50.4° after the treatment of the membrane at the optimal gaseous phase ozonation. This indicates an increase in the hydrophilicity of the treated membrane. Also, filtration performance demonstrated a lower fouling occurrence on the treated membrane as compared to the untreated one. Although gaseous ozonation yielded a slightly better performance in comparison to the aqueous treatment, the membrane treated with aqueous phase ozonation was benefited from conserving its mechanical strength. Activated carbon helped decreasing the contact angle and fouling as compared to the non-catalytic aqueous treatment while the tensile strength was not affected

Retention of Liquids Above Microporous Membranes

2003 ◽  
Vol 790 ◽  
Author(s):  
John Charkoudian ◽  
Volkmar Thom
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Surface Modification ◽  
High Throughput ◽  
Liquid Surface ◽  
Polymer Surface ◽  
Microporous Membranes ◽  
Droplet Spreading ◽  
Liquid Surface Tension ◽  
Multiwell Plates

ABSTRACTThe ability of membranes to retain fluids without leaking in devices such as high throughput multiwell plates was examined as a function of membrane polymer, surface modification, and liquid surface tension. Microporous membranes (200–800nm) act as arrays of millions of imperfect microcapillaries. Extrusion and leaking requires pressure plus coalescence of microdroplets. For unmodified membranes, the liquid hold up height (pressure) is critically dependent on liquid surface tension, rising rapidly when the contact angle prevents droplet spreading and coalescence. Topography, as measured by AFM, also plays a role in ease of coalescence. Surface modification has a large impact on hold up pressure and its dependence on liquid surface tension.

scholarly journals Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrzej Sikora ◽  
Dariusz Czylkowski ◽  
Bartosz Hrycak ◽  
Magdalena Moczała-Dusanowska ◽  
Marcin Łapiński ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Chemical Composition ◽  
Water Contact Angle ◽  
Plasma Sheet ◽  
Atmospheric Pressure ◽  
Argon Plasma ◽  
Fullerene Derivative ◽  
Water Contact ◽  
Pmma Polymer

AbstractThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number of plasma scans (up to 3) and, the kind of treated material. In order to assess the plasma effect, the possible changes in the wettability, roughness, chemical composition, and mechanical properties of the plasma-treated samples’ surfaces were evaluated by water contact angle goniometry (WCA), atomic force microscopy (AFM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The best result concerning the water contact angle reduction was from 83° to 29.7° for the PMMA material. The ageing studies of the PMMA plasma-modified surface showed long term (100 h) improved wettability. As a result of plasma treating, changes in the samples surface roughness parameters were observed, however their dependence on the number of plasma scans is irregular. The ATR-FTIR spectra of the PMMA plasma-treated surfaces showed only slight changes in comparison with the spectra of an untreated sample. The more significant differences were demonstrated by XPS measurements indicating the surface chemical composition changes after plasma treatment and revealing the oxygen to carbon ratio increase from 0.1 to 0.4.

scholarly journals Influence of moisture content on the contact angle and surface tension measured on birch wood surfaces

2021 ◽  
Author(s):  
Rami Benkreif ◽  
Fatima Zohra Brahmia ◽  
Csilla Csiha
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Moisture Content ◽  
Solid Wood ◽  
Contact Angles ◽  
Surface Moisture ◽  
Wood Coatings ◽  
The Relationship ◽  
Wood Surfaces

AbstractSurface tension of solid wood surfaces affects the wettability and thus the adhesion of various adhesives and wood coatings. By measuring the contact angle of the wood, the surface tension can be calculated based on the Young-Dupré equation. Several publications have reported on contact angle measured with different test liquids, under different conditions. Results can only be compared if the test conditions are similar. While the roles of the drop volume, image shooting time etc., are widely recognized, the role of the wood surface moisture content (MC) is not evaluated in detail. In this study, the effect of wood moisture content on contact angle values, measured with distilled water and diiodomethane, on sanded birch (Betula pendula) surfaces was investigated, in order to find the relationship between them. With increasing MC from approximately 6% to 30%, increasing contact angle (decreasing surface tension) values were measured according to a logarithmic function. The function makes possible the calculation of contact angles that correspond to different MCs.

scholarly journals Water uptake of various electrospun nonwovens

2020 ◽  
Vol 6 (3) ◽  
pp. 155-158
Author(s):  
Katharina Wulf ◽  
Volkmar Senz ◽  
Thomas Eickner ◽  
Sabine Illner
Keyword(s):  
Contact Angle ◽  
Surface Modification ◽  
Water Absorption ◽  
Water Uptake ◽  
Biomedical Applications ◽  
High Surface ◽  
Volume Ratio ◽  
Polymer Composition ◽  
Water Wetting ◽  
Morphology Changes

AbstractIn recent years, nanofiber based materials have emerged as especially interesting for several biomedical applications, regarding their high surface to volume ratio. Due to the superficial nano- and microstructuring and the different wettability compared to nonstructured surfaces, the water absorption is an important parameter with respect to the degradation stability, thermomechanic properties and drug release properties, depending on the type of polymer [1]. In this investigation, the water absorption of different non- and plasma modified biostable nanofiber nonwovens based on polyurethane, polyester and polyamide were analysed and compared. Also, the water absorption by specified water wetting, the contact angle and morphology changes were examined. The results show that the water uptake is highly dependent on the surface modification and the polymer composition itself and can therefore be partially changed.

scholarly journals New Synthetic Methods of Novel Nanoporous Polycondensates and Excellent Oxygen Permselectivity of Their Composite Membranes

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 859
Author(s):  
Yu Zang ◽  
Toshiki Aoki ◽  
Masahiro Teraguchi ◽  
Takashi Kaneko ◽  
Hongge Jia ◽  
...  
Keyword(s):  
Contact Angle ◽  
Upper Bound ◽  
Oxygen Permeability ◽  
Membrane Surface ◽  
Composite Membranes ◽  
Synthetic Methods ◽  
Preparation Methods ◽  
First Time

Two kinds of novel nanoporous polycondensates (sc(Rf)) have been synthesized by two new preparation methods consisting of polycondensation and highly selective photocyclicaromataization of 1/3 helical cis-cis polyphenylacetylenes with polymerizable groups. By the original methods, new well-defined sheet polymers having nanopores or nanospaces have been synthesized for the first time. Their composite membranes, containing small amounts (1.0 wt%) of sc(Rf), had ultrahigh oxygen permeability (Po2 > 1000 barrer), and their plots were beyond the Robeson’s upper bound line in the graph of oxygen permselectivity (α = Po2/PN2) versus Po2. Both α and Po2 values were enhanced by adding only small amounts (1.0 wt%) of sc(Rf). One of the sc(Rf)s synthesized on the base membrane surface showed the best performance, i.e., Po2 = 5300 barrer and α = 2.5. The membrane surface was effectively covered by sc(Rf), judging from the contact angle values. It is thought that nanopores and nanospaces created in and between sc(Rf) molecules played an important role for the enhancement of both α and Po2/PN2.

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