100


 =C 90






 o~ b2



 0 2 4 6 8
 Nanocapsule concentration (w%/)

Figure 6-10. Plot of normalized aqueous concentration of ferrocene methanol after uptake in 0.07
 wt % TMOS nanocapsule solution (bl, total concentration: 5.9 wt %; b2, total
 concentration: 6.2 wt %), in 0.28 wt % TMOS nanocapsule solution (c, total
 concentration: 1.9 wt %), in 0.44 wt % TMOS nanocapsule solution (d, total
 concentration: 1.9 wt %), and in 0.88 wt % TMOS nanocapsule solution (e, total
 concentration: 4.9 wt %). (a) Control experiment in the absence of nanocapsules.

 While further quantitative analysis is somewhat difficult to make, support from this

interpretation comes from the fact that the only cases where appreciable slower kinetics are seen

in Figure 6-9 are the two cases where the largest amount of TMOS was introduced in the

synthesis solution (curves d and e that respectively correspond to nanocapsule samples with 0.44

and 0.88 wt % TMOS), and therefore where thicker shells were obtained. For these two samples,

it takes approximately 200-300 s before the aqueous concentration of ferrocene methanol levels

off, whereas the thermodynamic equilibrium is reached almost instantaneously for the other three

samples with thinner silica shells (curves c and b that respectively correspond to nanocapsule

samples with 0.28 and 0.07 wt % TMOS).

 To further investigate silica shell/alcohol interactions, we carried out similar experiments

with ferrocene dimethanol. This substance displays a similar electroactivity with a slight shift in