Preparation of flexible and ultralow dielectric polyimide porous films by a low-cost and environmentally friendly non-solvent phase separation

Polyimide (PI) porous films were prepared by non-solvent induced phase separation with low-cost and simple method. A low-cost and environmentally friendly solution of water and ethanol was selected as non-solvent coagulation bath and effects of water and ethanol content on microstructure and properties was studied. The prepared films showed high mechanical property at high temperature, excellent dielectric property and thermal stability. Thus there are excellent application prospects in fields of flexible electronics and microelectronics industry.