2005-728 Ordered Vertically Oriented Porous Inorganic Films Produced through Solution Processing

Summary

UCLA Researchers in the Department of Chemistry and Biochemistry have developed a novel technique for fabricating vertically oriented porous films. Background There exists a wide range of applications for vertically oriented porous films, which can be used for the separation and filtration of solutions and electrical or magnetic contacts. Currently, these films can be produced using such methods as optical lithography and e-beam serial lithography, ion track etching, anodic alumina, aligned diblock copolymers, and various surfactant or polymer template materials. However, these techniques possess drawbacks including: scaling limitations, reduced throughput, and substrate restrictions. A technique for developing porous films free of the disadvantages found in the state of the art would be highly desirable.

Innovation

Researchers at UCLA have created a technique for producing vertically oriented inorganic pore systems via solution processing. Using this novel procedure, a hexagonal honeycomb structured surfactant or polymer templated inorganic-organic composite is grown on a cubic self-assembled patterned surface to form the vertically aligned pores. Unlike many traditional methods, this innovative procedure can utilize a variety of materials to form the film structure, which enhances substrate versatility. Additionally, the use of a cubic self-assembled liquid crystal system for a substrate to align a hexagonal self-assembled liquid crystal system allows the realization of superior feature size and material control.

Applications

• Separation or ultrafiltration in which solutions containing molecules or colloids are passed through a membrane made of templated vertical pores.
• Can be used for electromagnetic purposes.
• The properties of the inorganic framework can be modified according the characteristics of the material filling the pores: it can be insulating, semiconducting, or conducting.

Advantages

• Permits features between 2 and 20nm in size and definable pitch.
• Self-assembled systems offer unparalleled control over material composition and physical properties.

State of Development

Prototype silica films with 15nm pitch and 10nm diameter pores oriented vertically can be produced using cubic titania as a substrate.