The assemblies and application of silica and iron oxide nanostructures
Chong, Wen Han
Date of Issue2014
School of Physical and Mathematical Sciences
My work has been largely focused on the synthesis of magnetically controlled multifunctional nanostructures for applications, through the assembly of iron oxide nanostructures with subsequent structure preservation using silica via simple Stöber process. Several novel structures has been discovered and prepared. For example, silica encapsulation of hydrophobic liquid droplet consists of iron oxide for storing and releasing large amount of hydrophobic molecules. Due to the stable and porous shell, no rupturing or leakage of the hydrophobic liquid can be observed even after the release. Nanometer size magnetic stirring bars were prepared. They can be easily inserted into extremely small water droplets (4 pL) for parallel stirring and mixing. For those with thick silica coating, a contracted structure can be observed and the mechanism was investigated. Lastly, fluorescent silica shell was synthesized onto the nano stir bars using cheap dye molecules. The mechanism of formation was studied and the method was modified to prevent the massive aggregations.