Mesoscale structure and fractal nature of 1-propanol aqueous solution: A reverse Monte Carlo analysis of small angle neutron scattering intensity

摘要

Mesoscale structures of salt-free and salt-added 1-propanol aqueous solutions have been analyzed by means of a reverse Monte Carlo (RMC) technique combined with small angle neutron scattering data. RMC analysis is carried out by using sub-million molecules and concentration-fluctuation is visualized. Effect of salt on the mesoscale structure is also visualized. Origin of fractal nature of the solutions is attributed to the distribution of [g_pp(r)-g_pw(r)] and [g_ww(r)-g_wp(r)]. 1-propanol-rich regins are surrounded by thin water-layers in the salt-free solutions. The addition of salt shifts the thickness distributions of the water-layer to the larger value. However, the thickness distribution is scaled very well between the self-free solution and the salt-added solution, suggesting a self-similarity of mesoscale structure of both solutions. Formation of concentration-fluctuation and salt-induced phase separation are discussed.