Substrate hydrophylic

We have initiated a series of investigations to study the catalytic effects of a class of cationic polyelectrolytes ranging in solution behavior from "normal" polyions to polysoaps upon the alkaline hydrolysis of neutral and anionic phenyl esters of varying chain lengths. Employing these catalysts of varying hydrophylic-hydrophobic character in reactions of neutral and anionic substrates of varied hydrophilic-hydrophobic character, it should be possible to elucidate the contributions of both the hydrophobic interactions and electrostatic interactions on the rate of reaction. 

As discussed in Chapter 5, the pore size and hydrophobicity control the capillary pressure in the liquid. In a hydrophylic media, the smaller pore sizes have a liquid suction pressure, drawing liquid in. In the PAFC, the SiC matrix has uniformly small pores and is more hydrophilic than the catalyst layer or substrate reservoir, so that losses in electrolyte are readily replaced by suction from stored electrolyte these locations. The pressure and pore size distribution set up the electrolyte-catalyst-reactant interface area and thus are critical factors to control the performance of the electrode. The uniformity and control of the pore size in the matrix are extremely important to prevent local drainage spots with severe crossover. Control of the pore size distribution and hydrophobicity of the catalyst layer, substrate, and storage matrix are critical to ensure long life and maximized triple-phase boundary area for reaction in the catalyst layer. 

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