I have prepared two sols, one with complexing agent and other without complexing agent. Both the sols are stable and transperent, but when deposited films on glass substrate using dip coating, sol with complexing agent is (film) uniform and transparent and other sol without complexing agent is (film) hazy (white colour) and adherence is not good.
sol=precursor+solvent+complexing agent(optional).
Without any information regarding composition of the Complexing agent; it assumes that you change your sol-gel's surface tension by adding complexing agent
Alkoxide(precursor), alcohol(solvent) and ethyl acetoacetate(complexing agent) is the composition of the sol. Prof. Mehri and Dr. Alexandre.
A substance (Ethyl acetoacetat ) that reduces the surface tension of a liquid and affecting the liquid to spreads or more easily penetrates over the surface of a solid. Ethyl acetoacetat works as wetting agent and reduce the surface tension of your liquid.
in this case I assume that the presence of the ethylacetoacetate is there as a complexing agent (slow down the reaction) or as an acid to start the reaction of polycondensation du sol-gel.
You have Alkoxide(precursor with Li or may be Na); how about the reaction between a molecule of ethyl acetoacetate and alkoxide in your solvent (coordination band; ligand)?
Alexander, I am not convincing with your answer regarding a complexing agent (slow down the reaction) if we look back on application of EAA:
EAA as a solvent, a stabilizer or a catalyst (increase the rate ), a promoter or co-promoterd and EAA can be added on related surface coatings or textiles as an accelerant in the cure process.
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