Ammonia → Tetraethoxysilane

Participants

Reaction Steps

The mixture of 10 mg of each fluorescent dye compound of “FITC”-silane, “Rhodamine 6G”-silane and “Rhodamine B”-silane as described above is dissolved in 150 ml of ethanol (96% Merck) and the solution is added to a mixture of 200 ml of ethanol (96%, Merck), 30 g of 25% of ammonia and 100 ml of water under vigorous stirring. The modified “Stöber Process” is carried out during 24 h at room temperature under protection from light. After forming the seed particles (derivatives of R6G/FITC/Rhd B), 25 g of tetraethoxysilane (TEOS) dissolved in 100 ml of ethanol are added to form the silica shell. The mixture is stirred for additional 24 h and the core-shell particles are centrifuged. The residue is dispersed in ethanol, precipitated by addition of ethyl acetate, washed and centrifuged thrice until no starting material or unreacted compounds are found in supernatant. The residue is re-dispersed in ethanol until further use.

Provenance & Evidence