Tuning the Molecular Weights, Chain Packing, and Gas-Transport Properties of CANAL Ladder Polymers by Short Alkyl Substitutions

We used catalytic arene–norbornene annulation (CANAL) polymerization to synthesize high-molecular-weight (degree of polymerization 500–800 based on Mn) rigid ladder polymers with methyl, ethyl, and isopropyl substituents that can form self-standing films. The short alkyl substitution on CANAL ladder polymers significantly impacted gas-transport properties and their chain packing as revealed by variable-temperature pure-gas permeation and...