2. Experimental procedures
2.1. Reagents
Pluronic P123 triblock copolymer (Aldrich), tetraethylorthosilicate
TEOS (Merck) and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane
(Merck)were used. All organic solvents (HPLC grade)were fromMerck
chemical company. All acids used were of the highest purity available
from Merck. Analytical grade nitrate salts of elements (all from Merck)
were of the highest purity available and used without any further
purification. Doubly distilled deionized water was used throughout.