Christophe Castel

Tuning the morphology and the structure of hierarchical meso–macroporous silica by dual templating with micelles and solid lipid nanoparticles (SLN)

Solid lipid nanoparticles (SLN) stabilized by nonionic polysorbate or block copolymer surfactants were used for the preparation of hierarchical meso–macroporous silica through a co-templated approach combining a cooperative templating mechanism (CTM) with micelles and spherical soft matter particles imprinting. Depending on the reaction conditions, the morphology of the final material can be tuned to capsules or to block matter. The size of the mesopores is strongly dependent on the nature of the surfactant in excess: 3 nm (Tween 20), 5 nm (Tween 40) or 9 nm (Pluronic® P123), whereas the size of the macropores depends only on the size of SLN (250 ± 150 nm). The macroporous texture was clearly evidenced by TEM. The organization degree of the silica wall depends on the surfactant: only wormlike mesoporous capsules were obtained with Tween 20, and hexagonally ordered microdomains embedded in wormlike mesoporous silica capsules were obtained with Tween 40. Hexagonally ordered silica with circularly ordered mesoporosity could be achieved with Pluronic block copolymer P123. Combining mesoporous silica with solid lipid nanoparticles is a straightforward approach for the design of advanced formulations in drug delivery or food chemistry.