It is doubtful that temperature causes restoration of coherent compact of graphite structure in aqueous graphene dispersion. You can adopt XRD,AFM and SEM to study the effect of temperature on inter-layers distances , number of layers and thickness.

It is pretty difficult to disperse graphene in water, if not additionally stabilised. What type is your stabiliser of the suspension?

It is doubtful that temperature causes restoration of coherent compact of graphite structure in aqueous graphene dispersion. You can adopt XRD,AFM and SEM to study the effect of temperature on inter-layers distances , number of layers and thickness.

@Dimitar sir, there is a ketonic stabiliser. The dispersion is quite stable.

Then you lose your stabiliser upon heating, and your suspension agglomerates. This is very likely interconnected with the stabiliser concentration and the average size of the suspended particles (higher to for fine suspensions), so you should get the point experimentally for your conditions.