Qualitative and quantitative analysis of intercalated and exfoliated silicate layers in asymmetric polyethersulfone/cloisite15A® mixed matrix membrane for CO2/CH4 separation by Ismail, Nabawia M., Ismail, Ahmad F., Mustafa, Azeman, Matsuura, Takeshi, Soga, T., Nagata, Kenji, Asaka, T.