Growing Nanoballoons and Nanotubes of Pure Polymer from a Microcapsule

Abundant nanoballoons and nanotubes (less than 100 nm) of pure polymer have been grown from a hybrid microcapsule by programed heating. The hybrid microcapsule, comprising an organosilica shell and styrene core, was synthesized by a sol-gel reaction. Electronic microscopy confirmed that most of the growing nanostructures were nanoballoons of less than 100 nm with a thickness of 15 nm, while a few nanostructures were nanotubes with outer diameters around 20 nm. Infrared spectroscopy and thermogravimetric measurements were employed to analyze the composition of the hybrid spheres both qualitatively and quantitively. Based on the pore distribution on the microcapsule surface, the formation mechanism of these nanostructures was proposed in a schematic way. These interesting results encouraged us to develop a microdevice 'nano-extruder' from existing porous templates.