The unique proprties of polymers of intrinsic microporosity (PIMs) such as solution-processability and microporosity, organic materials appropriate for the building of membranes that make efficient molecular sieving. Molecular dynamics (MD) simulation was used to evaluate the diffusion coefficients of CO2, and N2 gas molecules in amorphous PIMs in the different temperature (453 and 493 K). The calculated diffusion coefficients of CO2 and N2 showed that N2 has the highest diffusion coefficient (9.65×10-5 cm2/s) at 493 K. Moreover, the diffusion coefficients of all two penetrant molecules increase with increasing temperature and a clear linear behaviour.
