Influence of processing induced textural effect on aggregation level in CuPc–SiO2 sonogel composites

Abstract Aggregation effects in metallophthalocyanine/SiO 2 composites play an important role in the optical properties of these materials. With the aim to decrease phthalocyanine self-association induced in aqueous solution into the network pores, alternative processing methods for trapping the organic in the matrices have been carried out. Monolithic xerogels have been obtained by three chemically different processing routes, preserving their homogeneity and transparency, even under extremely acid conditions. Micro, meso and non-porous silica xerogels have been obtained, depending on processing method. However, the organic doping highly modifies the textural features of the final composite, increasing the pore volume of composites even in more than 50%. Phthalocyanine aggregation degree has been tested by UV–VIS absorption spectroscopy and correlated to the textural parameters and pore size distribution of the composites. The effect of the textural features on molecular self-association level is evaluated.