Figure 7: Absolute value of zeta potential measurements derived from current monitoring experiments during a period of six weeks. Each data point is the average of 3-4 measurements, with the error bars representing the standard deviation. As expected, the uncoated channels are the most stable. Both zwitterionic coatings show large variations, with ZP’s ζ-potential approaching the value of an uncoated channel after 6 weeks. Both PEG and 3-MPS appear to be stable during the duration of the six week study.