Molecular Crystallization Controlled by pH Regulates Mesoscopic Membrane Morphology

ACS Nano ◽  
2012 ◽  
Vol 6 (12) ◽  
pp. 10901-10909 ◽  
Author(s):  
Cheuk-Yui Leung ◽  
Liam C. Palmer ◽  
Bao Fu Qiao ◽  
Sumit Kewalramani ◽  
Rastko Sknepnek ◽  
...  
Keyword(s):  
Membrane Morphology ◽  
Molecular Crystallization

scholarly journals Phenolphthalein Anilide Based Poly(Ether Sulfone) Block Copolymers Containing Quaternary Ammonium and Imidazolium Cations: Anion Exchange Membrane Materials for Microbial Fuel Cell

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 454
Author(s):  
Aruna Kumar Mohanty ◽  
Young-eun Song ◽  
Jung-rae Kim ◽  
Nowon Kim ◽  
Hyun-jong Paik
Keyword(s):  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Anion Exchange ◽  
Quaternary Ammonium ◽  
Anion Exchange Membrane ◽  
Anion Exchange Membranes ◽  
Good Thermal Stability ◽  
Imidazolium Cations ◽  
Membrane Morphology ◽  
Exchange Membrane

A class of phenolphthalein anilide (PA)-based poly(ether sulfone) multiblock copolymers containing pendant quaternary ammonium (QA) and imidazolium (IM) groups were synthesized and evaluated as anion exchange membrane (AEM) materials. The AEMs were flexible and mechanically strong with good thermal stability. The ionomeric multiblock copolymer AEMs exhibited well-defined hydrophobic/hydrophilic phase-separated morphology in small-angle X-ray scattering and atomic force microscopy. The distinct nanophase separated membrane morphology in the AEMs resulted in higher conductivity (IECw = 1.3–1.5 mequiv./g, σ(OH−) = 30–38 mS/cm at 20 °C), lower water uptake and swelling. Finally, the membranes were compared in terms of microbial fuel cell performances with the commercial cation and anion exchange membranes. The membranes showed a maximum power density of ~310 mW/m2 (at 0.82 A/m2); 1.7 and 2.8 times higher than the Nafion 117 and FAB-PK-130 membranes, respectively. These results demonstrated that the synthesized AEMs were superior to Nafion 117 and FAB-PK-130 membranes.

scholarly journals Effects of an Acetic Acid and Acetone Mixture on the Characteristics and Scaffold–Cell Interaction of Electrospun Polycaprolactone Membranes

2019 ◽  
Vol 9 (20) ◽  
pp. 4350 ◽  
Author(s):  
Minh Hieu Ho ◽  
Thien Bui-Thuan Do ◽  
Nhi Ngoc-Thao Dang ◽  
An Nguyen-My Le ◽  
Hanh Thi-Kieu Ta ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Cell Interaction ◽  
Fibrous Materials ◽  
Cell Adherence ◽  
Physical Strength ◽  
Membrane Morphology ◽  
Cell Scaffold ◽  
Different Types ◽  
Proliferation Assays ◽  
Cell Adhesion And Proliferation

Green electrospinning has attracted great interest since non-toxic solvents were shown to be applicable in the fabrication of fibrous materials while ensuring health safety and environmental protection. Less harmful reagents such as acetone (AC) and acetic acid (AA) have been employed in this field in recent years. However, research in this area is still rare, yielding only preliminary results. In this study, two different types of solvents (pure AC and an AA/AC mixture) were used to fabricate electrospun polycaprolactone (PCL) membranes. Sample morphology, wettability, tensile strength, and chemical composition were compared between two types of membranes. Cell–scaffold interaction was also examined by cell adhesion and proliferation assays. The results demonstrate that the two types of solvents had significant effects on membrane morphology, physical strength, and cell adherence behaviors, which should be considered for different application purposes.

An electron microscope study of kidney basement membrane changes in the mouse by lipoteichoic acid from Streptococcus pyogenes

1987 ◽  
Vol 33 (8) ◽  
pp. 709-717 ◽  
Author(s):  
Ofra Leon ◽  
Charles Panos
Keyword(s):  
Basement Membrane ◽  
Streptococcus Pyogenes ◽  
Membrane Damage ◽  
Lipoteichoic Acid ◽  
Poststreptococcal Glomerulonephritis ◽  
Membrane Morphology ◽  
Proximal Tubular ◽  
Weight Analysis ◽  
Membrane Changes ◽  
Almost All

Mice injected repeatedly, intraperitoneally or intravenously, for approximately 1 month with a total of 1.04 mg lipoteichoic acid from a nephritogenic strain of Streptococcus pyogenes lost weight. Analysis by electron microscopy revealed that they also exhibited extensive kidney changes in basement membrane morphology which resembled, in part, those observed in human poststreptococcal glomerulonephritis. For example, the glomerular basement membrane became electron dense and exhibited at least a twofold increase in width sporadically within the same preparation after exposure to lipoteichoic acid. Also, whereas appreciable loss or reduction in epithelial foot processes as a result of fusion was clearly evident, epithelial slits and slit membranes or diaphragms between normal foot processes were not selectively affected. In addition, another mostly thickened, highly coiled or serpentinelike basement membrane with amorphous nodules appeared in these preparations. This type membrane was not observed surrounding the capillary lumina and was the most pronounced abnormality apparent in almost all preparations from mice exposed to lipoteichoic acid. Likewise, the proximal tubular basement membrane became variable in width and increased in electron density in mice given lipoteichoic acid as compared with controls. In addition, this membrane was often punctuated with various morphological protrusions originating from only its thickened areas and which extended away from, and not into, the capillary space. This change was only associated with the basement membrane of the proximal tubular capillaries. All membrane changes persisted but gradually subsided, with normal kidney membrane morphology reappearing on the 4th day following the last injection of lipoteichoic acid. The use of mice and minute amounts of lipoteichoic acid to study membrane damage or change in the fine structure of the glomerular or proximal tubular areas at the immediate presymptomatic, and very early symptomatic, phase of streptococcal glomerulonephritis is noted.

Highly gas permselective polyetherketone hollow fibre membranes using aqueous sulfuric acid solution as coagulant

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Jiping Yang ◽  
Philip J Brown
Keyword(s):  
Mechanical Properties ◽  
Sulfuric Acid ◽  
Acid Solution ◽  
Gas Separation ◽  
Sulfuric Acid Solution ◽  
Hollow Fibre ◽  
Injection Rate ◽  
Fluid Injection ◽  
Aqueous Sulfuric Acid ◽  
Membrane Morphology

AbstractHollow fibre membranes with more sponge-like morphology and improved gas permeation performance were spun from 20% polyetherketone (PEK) /sulfuric acid (H2SO4) dope solution with aqueous sulfuric acid solution as coagulant using dry-jet wet spinning process. The membrane morphology, mechanical properties and gas separation performance (hydrogen, methane and carbon dioxide) of as-spun PEK hollow fibres have been measured using SEM, Instron and gas test rig. Better cross section structures and mechanical properties in as-spun PEK hollow fibres were observed when aqueous sulfuric acid solution replaced water as coagulant (internal and external). The hydrogen/methane selectivity of up to 40 and hydrogen permeation rate of 3.65 GPU obtained in PEK hollow fibre membranes using 30% sulfuric acid solution as internal and external coagulant simultaneously at the bore fluid injection rate of 30 ml/h are higher than those reported in literatures. Furthermore the effects of bore fluid injection rate and various coagulants on the membrane morphology, mechanical properties and gas separation properties were investigated, as well.

An association between ear and tail morphologies of bats and their foraging style

2011 ◽  
Vol 89 (2) ◽  
pp. 90-99 ◽  
Author(s):  
James D. Gardiner ◽  
Jonathan R. Codd ◽  
Robert L. Nudds
Keyword(s):  
Body Size ◽  
Foraging Strategy ◽  
Aerodynamic Performance ◽  
Variance Analysis ◽  
Flight Performance ◽  
Wing Membrane ◽  
Trade Off ◽  
Scaling Relationships ◽  
Membrane Morphology ◽  
Foraging Flight

Most studies relating bat morphology to flight ecology have concentrated on the wing membrane. Here, canonical variance analysis showed that the ear and tail morphologies of bats also strongly relate to foraging strategy, which in turn is correlated with flight style. Variations in tail membrane morphology are likely to be a trade-off between increases in the mechanical cost of flight and improvements in foraging and flight performance. Flying with large ears is also potentially energetically expensive, particularly at high flight speeds. Large ears, therefore, are only likely to be affordable for slow foraging gleaning bat species. Bats with faster foraging flight styles tend to have smaller ears, possibly to cut the overall drag produced and reduce the power required for flight. Variations in the size of ears and tail membranes appear to be driven primarily by foraging strategy and not by body size, because the scaling relationships found are either weak or not significant. Ear size in bats may be a result of a trade-off between acoustic and aerodynamic performance.

scholarly journals An Experimental Investigation: Effect of Phase Inversion Methods on Membrane Structure and Its Performance on PEG Filtration

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Masooma Irfan ◽  
Hatijah Basri ◽  
M. Irfan
Keyword(s):  
Phase Separation ◽  
Phase Inversion ◽  
Multiwall Carbon Nanotubes ◽  
Polymeric Membranes ◽  
Inversion Method ◽  
Inversion Process ◽  
Membrane Morphology ◽  
And Performance ◽  
Phase Inversion Method ◽  
Multiwall Carbon

In this work, the effect of different phase inversion process on membrane morphology and performance was studied. Polyethersulfone (PES) based polymeric membranes was fabricated containing polyvinylpyrrolidone (PVP) and carboxylic functionalized multiwall carbon nanotubes (MWCNT) as additives and polyethylene glycol (PEG) having a molecular weight 1K, 10K and 35K (Dalton) were used as a model solution for observing the rejection/filteration ability of fabricated membranes. Non-solvent induce phase separation (NIP) and dry-wet phase separation (DWP) method was adopted for membrane synthesis. The FTIR spectra showed that PVP/MWCNT was effectively blended with PES polymer and different phase inversion method led to different internal morphologies of membranes as confirmed by FESEM images. The PEG rejection results suggested that membranes formed by DWP method had approximately double rejection ability than membranes formed by NIP process.

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