Multicore Capsules: Thermo‐Stimulable Wax@Water@SiO2 Multicore‐Shell Capsules (Part. Part. Syst. Charact. 2/2013)

Complex wax@water@SiO₂ multicore capsules are synthesized by combining sol‐gel process and formulation of wax‐in‐water‐in‐oil double emulsions. The inner direct wax‐in‐water emulsion is stabilized with modified silica nanoparticles using limited coalescence occurring in Pickering emulsions. In a second step, this obtained liquid dispersion is emulsified in poly‐dimethylsiloxane (PDMS) using a non ionic surfactant to stabilize the second water/oil interface. Finally, a sol‐gel process is employed to mineralize the as‐generated double emulsions giving rise to wax@water@SiO₂ multicore capsules. Due to the wax volume expansion through melting, the as‐synthesized multicore capsules offer thermally stimulated release that is enhanced when surfactant is added in the surrounding continuous oil phase. In addition, the melted wax release can be tuned from a one‐step process to a more sequential dropping mode by varying the mineral precursor tetraethoxy‐orthosilane (TEOS) concentration in the oily phase during mineralization.