| 초록 |
Simple and facile method to fabricate SiO2 micro- or nanotubes has been demonstrated, based on room temperature wet chemical oxidation of porous layer of Si pillar templates that have been prepared by metal-assisted chemical etching (MaCE). Under typical conditions, Si pillars produced by the MaCE have been found to be covered with thin nanoporous Si layer. The porous Si skin layer has been chemically oxidized by simple dipping in AgNO3 solution at room temperature, which has led to seamless SiO2 shell layer thanks to the accompanying volume expansion during the wet oxidation. Following wet removal of core Si by KOH yields the SiO2 micro- or nanotubes, either in test tube shape or in open shape at both ends, depending on processing method. The vertical arrays of SiO2 tube on Si substrate, after hydrophobic siloxane oligomer printing, has been found to have very large loading capacity on water, due to extremely high porosity (＞90%) and good enough mechanical stability. The simple and easy way to prepare the SiO2 tube can shed new light in design of novel aquatic devices, other than simple mimicking the leg of water strider. Also, the method may be very helpful in various applications of SiO2 nanotubes, such as drug delivery, enzyme immobilization, bio-separation, etc. |
