Polymer membrane ISEs, fabrication

Wang, L. S., Chow, P. Y, Phan, T. T., Lim, I. J., Yang, Y. Y. (2006). Fabrication and characterization of nanostructured and thermosensitive polymer membranes for wound healing and cell grafting. Advanced Functional Materials, 16, 1171-1178. 

Cho, Y. H., Yoo, S. J., Cho, Y. H., Park, H. S., Park, I. S., Lee, J. K., and Sung, Y. E. Enhanced performance and improved interfacial properties of polymer electrolyte membrane fuel cells fabricated using sputter-deposited Pt thin layers. Electrochimica Acta 2008 53 6111-6116. 

Gel polymer lithium-ion batteries replace the conventional liquid electrolytes with an advanced polymer electrolyte membrane. These cells can be packed in lightweight plastic packages as they do not have any free electrolytes and they can be fabricated in any desired shape and size. They are now increasingly becoming an alternative to liquid-electrolyte lithium-ion batteries, and several battery manufacturers. such as Sanyo. Sony, and Panasonic have started commercial production.Song et al. have recently reviewed the present state of gel-type polymer electrolyte technology for lithium-ion batteries. They focused on four plasticized systems, which have received particular attention from a practical viewpoint, i.e.. poly(ethylene oxide) (PEO). poly (acrylonitrile) (PAN). ° poly (methyl methacrylate) (PMMA). - and poly(vinylidene fluoride) (PVdF) based electrolytes. ... 

Nondegradable polymers are also useful as matrices for ocular implants. This application requires the polymer to be hydrophilic, to minimize local tissue irritation. Need for ocular implants stems from the challenges posed to conventional ocular medicines (i.e., eye drops) such as rapid dilution, tear washout, poor patient compliance, and limited bioavailability. Ocular implants from hydrophilic polymer matrices that provide localized sustained release may overcome the above limitations. The first polymeric sustained release product to reach the market was Ocusert , a pilocarpin sustained release ocular implant developed by Alza. Ocusert has the drug reservoir as a thin disc of pilocarpine-alginate complex sandwiched between two transparent discs of microporous membrane fabricated from ethylene-vinyl acetate copolymer. The microporous membranes permit the tear fluid to penetrate into the drug reservoir compartment to dissolve pilocarpine from the complex. Pilocarpine molecules are then released at a constant rate of 20 or 40 pg/hr for a four- to seven-day management of glaucoma. 

In this investigation, a sample of Nafion NX-90209 chlor-alkali membrane was used (E.I. du Pont de Nemours and Co., Polymer Products Department, Wilmington, DE). This membrane has sulfonate and carboxylate polymer layers and is reinforced with an open weave fabric. 

The development of solid polymer electrolyte cells is being actively conducted at General Electric Co. (13) and at Brown Boveri Research Center, Baden, Switzerland (14). As the name implies, the solid polymer electrolyte technology uses a solid polymer sheet as the sole electrolyte in the cells. It also acts as the cell separator. The majority of the present applications use Nafion with a thickness of 10-12 mils (13). Selected physical and chemical properties of Nafion 120 membranes are given in Table I. The membrane is equilibrated in water to approximately 30% water content prior to fabrication into a cell assembly. The hydrated membrane is highly conductive to hydrogen ions. It has excellent mechanical strength, and it is very stable in many corrosive cell environments. 

Furthermore, the FT-IR analytical technique was ap>plied in analysis of surface of membranes interacted with other materials. For instance, Luo et. al., fabricated the SPES/Nano-Ti02 composite ultrafiltration membrane. In their studies, the Ti02 nanoparticle self-assembly on the SPES membrane surface was confirmed by X-ray photoelectron spectroscopy (XPS) and FT-IR spectrometer. When the nano-TiCb was self-assembled on the SPES membrane the absorption peak at 1243 cm-i attributes to the stretching vibration of the ether C-O-C bond in the SPES polymer shifted to 1239 cmri. The result of FT-IR spiectrometer effectively verified the self-assembly process of nano-Ti02 on the SPES membrane.P ... 

Carbon constitutes the most abundant element of the different FC components. Setting aside the membrane, which is a polymer with a carbon backbone, all the other components, i.e. the CL, GDL and current collector plates (bipolar plates) are made almost entirely of graphitic carbon. The electrocatalyst support of the CL is commonly carbon black in the form of fine powder. GDLs are thin porous layers formed by carbon fibers interconnected as a web or fabric, while current collector plates are carbon monoliths with low bulk porosity. As explained above each of these components has a particular function within the fuel cell and in particular in the triple phase boundary. The structure and properties of the carbon in each of the different FC components will determine the whole performance of the cell. 

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