Ultrathin polymer membranes for high throughput CO₂ capture

Robust ultrathin polymer membranes offer significant technical and economic advantage over conventional carbon capture methods due to their potential for high throughput, high selectivity, and relative ease of implementation. We have been developing a simple, ultrathin, polymer membrane system to capture CO ₂ from post-combustion industrial exhaust streams. The approach involves nano-engineered membrane fabrication using an LLNL-developed solvent-less vapor deposition followed by in-situ polymerization (SLIP) process. The SLIP process vapor deposits ultrathin polymer films onto high throughput substrates to fabricate composite membranes. Single component gas permeation tests for PMDA-ODA films with thicknesses between 100-1000 nm were conducted. Permeability was found to be in the 30-100 Barrer range while maintaining CO₂/N₂ selectivity of ∼20:1. Membrane performance may be enhanced via improved film quality, reduced thickness, the development of new materials which are compatible with the SLIP process, and a modeling effort to understand the underlying transport phenomena within the membrane material.