Molecular Simulation of Amine-PIM-1: Comparison of experimental and theoretical Sorption Isotherms of molecular gases in a modified Polymer of Intrinsic Microporosity

Atomistic molecular modelling techniques have confirmed to be a very useful tool for the investigation of the structure and dynamics of dense amorphous membrane polymers and of transport processes in these materials [1]. In recent years, polymers of intrinsic microporosity (PIMs) are emerging materials characterized by high free volume above 20% [2] and they will be promising materials for making organic membranes suitable for gas separation. In this paper, we study polymer of intrinsic microporosity (PIMs), in particular, the Amine-PIM-1 that contains four nitrile groups randomly spaced (functionalization percentage of 85%). In adsorption experiments, the novel amine-PIM-1 showed higher CO2 uptake and higher CO2/N2 sorption selectivity than the parent polymer, with very evident dual-mode sorption behaviour [3]. Simulation of polymeric models is not trivial due to the difficulty in packing the polymeric chains in the correct configurations in order to obtain realistic results from the simulation. Here we will explain the polymeric matrix construction and the results obtained for the CO2/N2 separation [4]. We focus on the comparison between experimental and theoretical single gas-adsorption isotherms of several small molecular gases such N2, CO2 and CH4 by using Grand Canonical Mont Carlo (GCMC) method. Acknowledgements The work leading to these results has received funding from the European Union's Seventh Framework Program (FP7/2007-2013) under grant agreement n° 608490, project M4CO2. This work was further supported by the CNR/FCT Italian/Portuguese bilateral project 2015-2016 "Advanced studies of the transport properties and gas separation by Polymers of Intrinsic Microporosity (PIMs) and Ionic Liquid Gel Membranes via novel methods" [1]D. Hofmann, L. Fritz et al.; Macromol. Theory Simul., 2000, 9, 293-327. [2]D. Fritsch, P.M. Budd et al.; Macromolecules 2010, 43, 6075-6084. [3]C. R. Mason, J. C. Jansen et al.; Macromolecules 2014, 47, 1021-1029. [4]E. Tocci, P. Pullumbi; Molecular Simulation 2006, 32,145-154.