Preparation of polymer films with enhanced ion conductivity via 3-D controlled ionic nanochannels

Poly(styrene-block-4-vinylpyridine) (PS-b-4PVP) with Mw of 58000 and PS/4PVP ratio of 4 was prepared using anionic polymerization. The prepared PS-b-4PVP showed microphase-separated nano-structures of cylinders after casting films. The cylindrical nano-structures were used to construct 3-D ordered ionic nanochannels for the transport of protons by simply attaching sulfonate groups to the pyridine units in PS-b-4PVP. The resulting films show highly asymmetric conductivity (0.015 S/cm to the vertical direction and very low conductivity (<1015S/cm to the lateral direction) at 25 °C with 45% relative humidity.