Fabrication of honeycomb membranes from soluble polyimides

Three kinds of soluble polyimides were synthesized by two -step method. The ordered honeycomb soluble polyimide membranes were prepared by casting the polymer solution on a solid substrate in a high humid environment. The mechanism of the formation of polyimides honeycomb membranes was proposed. Moreover, the deformation of the pore shapes by stretching and blowing was also tested. At last, the thermal stability of honeycomb-patterned films was investigated. It is shown that the honeycomb structures are stable at 350 °C.