The design of block copolymers and the control over their structures for energy storage

Herein we describe a method for controlling the mesoporous nanostructures in block copolymers and their subsequently converted porous carbons. We systematically investigated the self-assembly behavior of polyacrylonitirle-block-polymethyl methacrylate (PAN-b-PMMA) after thermal and solvent annealing, as well as the pore size of mesoporous carbon thin films after pyrolysis. The as-spin-coated PAN-b-PMMA microphase-separated into globular nanostructures, and the globular nanostructures evolved into various morphologies after thermal or solvent annealing. Surprisingly, after thermal annealing and pyrolysis, the pore size and center-to-center spacing of the mesoporous carbon thin films increased significantly with the increasing annealing temperature, which differed from most block copolymers. In addition, the choice of solvent during solvent annealing strongly influenced the block copolymer nanostructures and the pore size of mesoporous carbon thin films. The porous carbon structure was applied as electrodes in supercapacitors and exhibited outstanding surface area-normalized capacitance and gravimetric capacitance.