For higher performances of anion exchange membrane (AEM) fuel cells, understanding the phase separated structures inside AEMs is essential, as well as those at the catalyst layer/membrane interfaces. The AEMs based on quaternized aromatic semi-block copolymers with different ion exchange capacities (IECs) were systematically investigated. With IECs of 1.23 and 1.95 mequiv g(-1), the water uptakes at room temperature were 37% and 98%, and the anion conductivities 23.6 and 71.4 mS cm(-1), respectively. The increases were not proportional to the IEC. Images obtained by transmission electron microscopy in vacuum were similar with both IEC values, but the development of a clear phase separation in humidified nitrogen was observed in the profiles only with 1.95 mequiv g(-1) obtained by small angle X-ray scattering. At the temperature of 40 degrees C and the relative humidity (RH) of 30%, the average currents observed at the tip apex by current-sensing atomic force microscopy were <0.5 and 10 pA with 1.23 and 1.95 mequiv g(-1), respectively, and those at 70% RH were 10 and 15 pA, respectively. The humidity gave a larger influence on the bulk structure with 1.95 mequiv g(-1), whereas a larger influence on the surface conductivity with 1.23 mequiv g-1. (C) 2017 Elsevier B.V. All rights reserved.