(570c) Bulk Material Dissolution Zeolite Syntheses In The Presence Of Emulsions: Large Zeolite Crystals With Unusual Morphologies

The synthesis of zeolite crystals with controllable size and morphology represents a daunting challenge to the materials chemistry community. However, the rewards will be many as the ability to make such crystals will lead to new applications for zeolites as sensors, containers for nanowire growth, and model materials for studying basic phenomena such as transport in zeolites. Our lab has been actively involved in the synthesis of zeolites in the presence of emulsions to modulate crystal growth. Here we will report on recent work from our lab wherein the goal is to form large (> 50 micron) crystals of zeolites with unusual, and ideally controllable, crystal habits. Initial work has focused on silicalite-1 employing the bulk material dissolution method initially reported by Shimizu in the presence of oil/water/surfactant mixtures. Our results show that not only can one obtain large crystals of silicalite-1, but by manipulating 1) the mixture composition and 2) the surfactant charge it is possible to make conventional coffin-shaped crystals with different spatial orientation (i.e. b, not c is the long axis) as well as different morphologies such as long needles. We will present a summary of how surfactant identity/charge, mixture composition, and fluorine content impact the morphology of the crystals obtained, particularly in the context of how these variables affect the relative rates of nucleation and growth. Ongoing work which will also be presented will extend this work to other zeolite phases including the high-silica phases ZSM-12 and VPI-8, as well as low-silica zeolites including analcime and cancrinite.