For GISAXS measurement under full hydration, GMO60HEA5 and GMO55HEA10 films were immersed in excess water for 10 min. The GISAXS patterns show diffraction spots from highly oriented inverse bicontinuous cubic structures. The diffraction spots of the fully hydrated GMO60HEA5 film were simulated in an Ia3d or Pn3m phase, changing the orientation iteratively.