P. Lemoine et al., Swelling and delamination of multi-electrode sensor arrays studied by variable-pressure scanning electron microscopy, J BIOMED MR, 50(3), 2000, pp. 313-321
Multi-electrode sensor arrays are made of soft and wet materials not easily
examined by most microscopic techniques. in this paper, we have demonstrat
ed that low-vacuum scanning electron microscopy (LVSEM) and energy-dispersi
ve X-ray analysis (EDX) are adequate for studying the hydration, swelling,
and possible delamination of multi-electrode sensor arrays. We found that t
he LVSEM environment had no detectable effect on the morphology of Na+, K+,
and Ca++ sensors, and EDX analysis indicated that all three membranes have
similar compositions. However, once hydrated, the sensors exhibited differ
ent behaviors. The K+ and Ca++ sensors swelled more than the Na+ sensor did
. This swelling is due principally to water sorption in the membrane. We be
lieve that the larger thickness of the K+ and Ca++ membrane is partly respo
nsible for the observed swelling effect. A simple Griffith analysis of the
interface rupture confirms the experimental evidence that these thicker mem
branes also are more prone to delamination failure. (C) 2000 John Wiley & S
ons, Inc.