Guest-cooperative templating system for as-synthesis loading of guest molecules into ordered mesoporous silica materials

Abstract

A guest-cooperative templating system utilizing an interdependent micelle assembly of surfactant and guest has been developed to overcome the major disadvantages of as-synthesis loading methods such as low loading capacity and limitation on the type of guests. This system employs unique surfactants which cannot be effective in templating OMMs without suitable guests. Performance of the guest-cooperative templating system was evaluated using a nonionic surfactant, brij 78 [(C₁₈H₃₇ (O–CH₂CH₂)₂₀OH)] with a bulky hydrophilic head and an essential oil, eugenol, as a cooperative hydrophobic guest. High resolution TEM and SEM images reveal that a well-ordered hexagonal mesostructure is crystallized in a form of sphere-like particles. Reliable eugenol loading capacities could be increased nearly up to 10 wt%. It is also found that an elevated loading of eugenol leads to its increased stability within the mesopore. Therefore, this study successfully shows that maximized exploration of effective pore space could be realized through an interdependent micelle assembly of structurally different surfactant and guest.