solution with 0.5 mL of nanocapsule solution in 2.0 mL of water, 1 drop of Tween-80 in 2.5 mL

of water, and 2.5 mL of acidic water, respectively. For the fluorescence spectrum of Nile Red in

ethyl butyrate, 3 mL of ethyl butyrate was mixed with 0.5 mL of the Nile Red stock solution.

The ethyl butyrate layer was then pipetted into a glass cuvette, and the fluorescence spectrum of

the Nile Red in ethyl butyrate was recorded. For the silica gel experiments, a saturated solution

of Nile Red in ethanol was mixed with 2 g of silica gel and the excess solvent was evaporated to

adsorb Nile Red onto the silica gel. Finally, the Xerogel was prepared by allowing the drying of

a mixture of 12.5 mL of Nile-Red-saturated ethanol, 5.6 mL of tetraethoxysilane (Aldrich

Chemical Co.), and 0.9 mL of water with pH 3.4. The resulting gel was subsequently crushed

and placed in acidic water.

6.4.5 Electrochemistry Experiments

 The electrochemical studies were performed using an EG&G PAR 273 potentiostat,

interfaced to a PC computer. Cyclic voltammetry experiments were carried out in a three-

electrode 10 mL electrochemical cell. The working electrode used was a 1 mm diameter disk

vitreous carbon electrode polished on a diamond paste covered rotating disk (Presi) prior to each

experiment. The auxiliary electrode was a platinum wire, and the reference electrode (Ag /Ag

electrode filled with 0.01 M AgNO3) WAS checked versus ferrocene as recommended by IUPAC.

In our case, Ea(Fc /Fc) = 0.045 V in acetonitrile with 0.1 M tetraethylammonium perchlorate.

Ferrocene methanol and ferrocene dimethanol were purchased from Aldrich Chemical Co., and

lithium perchlorate was purchased from Fluka (puriss).

 The ferrocene methanol and ferrocene dimethanol aqueous solutions used contained 2x10-4

mol/L of either electroactive molecule and 10-1 mol/L lithium perchlorate used as the electrolyte.

A typical uptake experiment was carried out as follows: an initial cyclic voltammogram is

recorded for 5 mL of ferrocene methanol or ferrocene dimethanol solution in the electrochemical