Oxygenator, microchannel membrane

Fig. 7.22 Schematic of a microchannel membrane oxygenator form vitro testing [2811.

Another way to use silicon wafers as DLs was presented by Meyers and Maynard [77]. They developed a micro-PEMFC based on a bilayer design in which both the anode and the cathode current collectors were made out of conductive silicon wafers. Each of fhese componenfs had a series of microchannels formed on one of their surfaces, allowing fhe hydrogen and oxygen to flow through them. Before the charmels were machined, a layer of porous silicon was formed on top of the Si wafers and fhen fhe silicon material beneath the porous layer was electropolished away to form fhe channels. After the wafers were machined, the CEs were added to the surfaces. In this cell, the actual diffusion layers were the porous silicon layers located on top of the channels because they let the gases diffuse fhrough fhem toward the active sites near the membrane. 

In conjunction with membrane-based blood oxygenators for example, microchannels offer improved gas exchange efficiency and reduce the volume of blood required for initial priming. A device developed by Himg et al. [281] involves a stack of 16 plate units incorporating 110 pm deep by 230 pm wide microchannels sandwiched with oxygen permeable membranes (Fig. 7.22). Experimental results not only show improved gas exchange efficiency over both macrochannels and theoretical predictions, but also a reduction in apparent blood viscosity. 

---