Novel Fabrication of Three-Dimensional Homogeneous Microporous Polyimide Membrane

Abstract

A polyimide porous membrane was fabricated using a relatively simple novel process. The process involves making a coating from a polyamic acid solution in which silica fine particles were dispersed, baking it for imidization, etching it with HF for silica removal, and controlling pore size with alkaline solution. In order to construct a porous structure, removal of silica fine particles by HF and control of pore diameter by an alkali solution were effective. Surface and cross section observation of the porous membrane by SEM and pore size measurement by a perm-porometer revealed that the membrane had a three-dimensional homogeneous microporous structure. Thermal analysis and organic solvent immersion testing confirmed the high heat resistance and chemical resistance of the porous membrane. The unique features revealed in this testing suggest that this porous membrane has various potential applications.

Application of Polyimide Porous Membrane to Photopolymer Filter

“…In order to clarify the adsorption mechanism of the porous polyimide membrane, the filtration test of T001 was carried out with three types of membranes having the same porosity and film thickness but different pore size. As in our previous report, membranes with different pore sizes were prepared by dispersing silica fine particles in polyamic acid and removing silica after imidization [7]. Porous membranes were fabricated with silica whose diameters were 100 nm, 300 nm, and 2500 nm.…”

“…We focused on polyimide which has high purity and excellent chemical resistance as a filter membrane for semiconductors. In our previous paper, we reported on polyimide porous membranes with fine pores and high specific surface area prepared by dispersing micro silica in polyamic acid and removing silica after imidization [7].…”

In-Situ Observation of Permeation Behavior and Structural Analysis of Polyimide Membrane with Electrical Properties

“…Porous polyimide is clean and excellent in heat resistance and chemical resistance, so it is suitable for semiconductor filter membrane. In the previous paper, we reported on a process for fabrication a polyimide porous membrane with a pore size of nano order suitable for semiconductor filter membranes [1].…”