Sol-gel method can be used to prepare both film with compact microstructure and powders with low aggregation. I want to know the key factor for achieving these two different microstructure. Can anyone give me some suggestion, or we can disscuse in this section.
1. For thin film preparation, spin coat your solution on substrate. and do the drying and annealing at particular temperature.
2. For powder preparation, do the continuous stirring of solution and make it in gel form and dry.
Drying temperature vary material to material and on your solvent.
Do you mean drying temperature is the key factor for the status (films or particles) of products?
In the first stage, the sol-gel process of the hydrolysis and polycondensation reaction leads to the formation of a colloidal solution-sol-hydroxide particles, whose size does not exceed several tens of nm. An increase in the volume concentration of the dispersed phase or other changes in external conditions (pH, solvent replacement) lead to an intensive formation of contacts between the particles and the formation of a monolithic gel in which the solvent molecules are enclosed in a flexible but sufficiently stable three-dimensional grid formed by hydroxide particles.Therefore, the main factor is the execution of the procedures of the first and second stages with respect to obtaining the desired product.The main factors are many.
@Yuri Mirgorod Thank you for your answer. Particles are firsted nucleared and then grown up from gel. So if I want to obtain a compact film, the particles should be sintered and densitifiction before it grows up?
To get a film, you better distribute the sol in film, and then sinter. Then we get a more homogeneous film. If you are preparing a film of sintered particles, then the film will not be strong. Again, all this depends on the precursors, the temperature, the problem that needs to be solved. We need experience.
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