On the Phase B of Comb-Like Poly(α-alkyl-β-L-aspartate)s: A Simulation of the Solubility of Small Penetrants

Abstract

The structure and thermal properties of the phase B of poly(α-alkyl-β-L-aspartate)s, abbreviated PAALA-n (n being the number of carbon atoms in the linear alkyl side chain), with n = 14 and 16 were determined using X-ray diffraction and DSC methods, respectively. These data together with those previously reported by us for the dodecyl derivative were used to perform Monte Carlo simulations of these comb-like polymers. The results allowed to predict the solubility of different gases in the phase B of PAALA-n. The variation of both the unoccupied space and the excess chemical potential with the size of the penetrant were computed. An attractive interaction between the polymer matrix and the penetrants was found when small gases were considered. The results have been compared with those recently obtained for crystalline poly(α-alkyl-β-L-aspartate)s bearing short linear alkyl side chains.