Confocal membrane characterization

Zeolite membranes are commonly characterized by SEM, XRD. TEM, EPMA, SEM-EDX, TEM-EOS, and Nitrogen adsorption are also used to study the morphology, microstructure and composition of zeolite membranes. Usually single gas permeation, mixed gas separation, pervaporation and vapor permeation are performed to evaluate the properties of zeolite membranes. Recently, some novel characterization techniques have been applied. Infrared reflectance measurement was used to characterize membrane thickness [19]. Fluorescence confocal optical microscopy was used to image the grain boundary structure of zeolite membranes [20]. FTIR-ATR method was used to characterize the T-O vibration of zeolite membranes [21],... 

Various planar membrane models have been developed, either for fundamental studies or for translational applications monolayers at the air-water interface, freestanding films in solution, solid supported membranes, and membranes on a porous solid support. Planar biomimetic membranes based on amphiphilic block copolymers are important artificial systems often used to mimic natural membranes. Their advantages, compared to artificial lipid membranes, are their improved stability and the possibility of chemically tailoring their structures. The simplest model of such a planar membrane is a monolayer at the air-water interface, formed when amphiphilic molecules are spread on water. As cell membrane models, it is more common to use free-standing membranes in which both sides of the membrane are accessible to water or buffer, and thus a bilayer is formed. The disadvantage of these two membrane models is the lack of stability, which can be overcome by the development of a solid supported membrane model. Characterization of such planar membranes can be challenging and several techniques, such as AFM, quartz crystal microbalance (QCM), infrared (IR) spectroscopy, confocal laser scan microscopy (CLSM), electrophoretic mobility, surface plasmon resonance (SPR), contact angle, ellipsometry, electrochemical impedance spectroscopy (EIS), patch clamp, or X-ray electron spectroscopy (XPS) have been used to characterize their... 

There are other modern spectroscopic methods such as X-ray photoelectron spectroscopy (XPS), small angle neutron scattering (SANS), Raman spectroscopy (RS), electron spinning resonance (ESR) and nuclear magnetic resonance (NMR). These techniques are well known in the membrane field. Static secondary ion mass spectrometry (SSIMS), energy dispersive X-ray spectroscopy (EDS), laser confocal scanning microscopy (FCSM) and environmental scanning electron microscopy (ESEM) can also be added to new microscopic methods to characterize the membranes [84]. 

Confocal Scanning Laser Microscopy Fundamentals and Uses on Membrane Fouling Characterization and Opportunities for Online Monitoring... 

Thanks to all the enhancements developed in the past decades, confocal Raman spectroscopy is now a technique of choice for the characterization of synthetics membranes [17-19] and chemical heterogeneous systems [20]. 

Sundhohn s research was well summarized in a review article [ 129], including the description and characterization of novel polymer electrolyte membranes for low-temperature fuel cells. Membranes made of PVDF-g-PSS A graft copolymers, cross-linked by divinylbenzene (and/or bis(vinylphenyl)ethane) [131,134,135], were compared with noncross-hnked membranes. The authors observed that the ion conductivity of the cross-hnked membranes was lower than that of noncross-hnked ones (induced by the inefficient sulfonation of the cross-linked materials and also by low water uptake at a low degree of grafting). Confocal Raman spectroscopy was used to characterize the PVDF-g-PSS A membranes in fuel cell conditions [136], finding that the cross-hnked membranes did not undergo the degradation noted with the noncross-hnked films. 

Charcosset, C., Cherfi, A., and Bemengo, J.-C. (2000). Characterization of microporous membrane morphology using confocal scanning laser microscopy. Chem. Eng. Sci. 55, 5351. 

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