Magnetic induced orientation of mesochannels

International Center for Materials Nanoarchitectonics
Yusuke Yamauchi
Center for Materials Nanoarchitectonics, Nano Ceramics Center
Yoshio Sakka, Noriyuki Hirota

Mission

Mesoporous silica, which contains mesoscale pores (from 2 nm to 50 nm), is a porous ceramic consisting of silicon dioxide (silica). In particular, mesoporous films have extremely high transparency, and are expected to be applied to optical materials and electronic materials. However, in general mesoporous films with tube-shaped mesopores, the direction of the mesochannels is parallel to the substrate, which has hindered advanced applications of the mesoporous films. To overcome it, we have newly proposed an ultrahigh magnetic field (> 30 Tesla) process.
Utilizing the force of the magnetic field, we manipulated the arrangement of the surfactant molecules which function as the template for the mesopores. Under an ultra-high field of 30T class, the surfactant behaves like a magnetic material and can be simply oriented in the direction of the magnetic field. Therefore, a high field was applied during the process of self-assembly of the surfactant molecules, thereby aligning the surfactant template perpendicular to the substrate in advance, and the periphery of the surfactant was then fixed with silica.

Orientation model of the assembly of the surfactant assemblies (template) in high magnetic field.	Cross-sectional TEM image of a slice of the substrate in the normal direction.

Technical characteristic

・Because this technique can be applied to various surfactants with different sizes, precise control of the pore diameter is possible.
・It would be possible to produce a next-generation ultra-high density magnetic recording medium by embedding magnetic particles into the perpendicularly oriented mesochannels.
・This structure would provide easy access into the thin film for a variety of substances, opening the way to other applications such as high activity catalysts and high sensitivity sensors, among others.