Polyacrylonitrile vapor separation

Porous membranes can be made of polymers (polysulfones, polyacrylonitrile, polypropylene, silicones, perfluoropolymers, polyimides, polyamides, etc.), ceramics (alumina, silica, titania, zirconia, zeolites, etc.) or microporous carbons. Dense organic membranes are commonly used for molecular-scale separations involving gas and vapor mixtures, whereas the mean pore sizes of porous membranes is chosen considering the size of the species to be separated. Current membrane processes include microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), gas and vapor separation (GS), and pervaporation (PV). Figure 1 indicates the types and sizes of species typically separated by these different separation processes. 

The first major application of microfiltration membranes was for biological testing of water. This remains an important laboratory application in microbiology and biotechnology. For these applications the early cellulose acetate/cellulose nitrate phase separation membranes made by vapor-phase precipitation with water are still widely used. In the early 1960s and 1970s, a number of other membrane materials with improved mechanical properties and chemical stability were developed. These include polyacrylonitrile-poly(vinyl chloride) copolymers, poly(vinylidene fluoride), polysulfone, cellulose triacetate, and various nylons. Most cartridge filters use these membranes. More recently poly(tetrafluo-roethylene) membranes have come into use. 

Flexible supercapacitors were made from PEDOT nanolibers as electrodes and polyacrylonitrile (PAN) nanolibers as separator by Larfogue et al. [19]. The PEDOT nanolibers were produced by combination of electrospinning and vapor-phase polymerization to form a conductive mat, and were used as the active material (electrodes), separated by a sheet of PAN nanolibers. Carbon-based clothes were used as the current collectors. The material layers were stacked together and embedded in a solid electrolyte containing an ionic liquid and polyvinylidene lluoride-co-hexa-fluoro-propylene (PVDF-co-HFP) as the host polymer. 

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