Method to produce nanoporous polymeric membranes

摘要

A method for making a flat polymer foam having a core layer of nano-sized open, interconnected cells that includes saturating a solid-state polymer with a supercritical fluid, allowing the gas to desorb for at least 35 minutes, and then heating the gas-saturated solid polymer for at least 3 minutes while constraining the foam in the thickness dimension. Any skin layer formed on the exterior may be removed via polishing, thus creating a foam with an open structure from side to side. The foam can be used as a battery separator.

主权项

1. A method for making a flat, blister-free foam with an open, interconnected cellular structure, comprising:
saturating a polymer with a gas in a vessel at conditions wherein the gas is supercritical and producing a gas-saturated polymer; desorbing gas from the gas-saturated polymer; placing the gas-saturated polymer in a press; in the press, heating the gas-saturated polymer at a temperature to allow cell growth while the press applies a clamping force to maintain flatness and produces a flat blister-free foam; and removing a solid skin layer from the foam to expose an open, interconnected cellular structure.