Quantum effects of hydrogen storage in e and d semicrystalline phases of syndiotactic polystyrene through adsorption

Syndiotactic polystyrene (sPS) is a stereoregular semicrystalline polymer which presents complex polymorphic behaviour and has been explored as an alternative for hydrogen storage using adsorp-tion. The methodology of gas retention using a light and cheap porous material offers many advantages. To establish the adsorption capacity of a specific material, adsorption isotherms are generally measured. However, to gain a better understanding of the underlying phenomena occur-ring at a nanoscale level (e.g. confined interactions of H-2 in sPS) and, moreover, as a predictive tool, alternative methods such as molecular simulations are required. In this work, we present Grand Canonical Monte Carlo simulation results for hydrogen (H-2) adsorption isotherms of (5 and e phases of sPS. H-2 molecule was described as a 1-site model with Lennard-Jones and Exp-6 potentials, within the Wigner-Kirkwood mean-field approximation to introduce quantum corrections. Both polymer phases were modelled using an atomistic force field and the initial configurations were relaxed using molecular dynamics for temperatures T = 45 K, 60 K and 77 K. Adsorption isotherms for each system were obtained for both classical and semiclassical potentials. Additionally, adsorption isotherms for both phases were compared with experimental adsorption data at 77 K from previous work.