Mesoporous carbon thin films have broad applications in filters, catalyst supports, electronics, gas separators and adsorbents, and energy conversion and storage devices. One of the most important features of mesoporous carbon thin films is their tunable pore size that determine the performance of mesoporous carbon. As a result, a technique that enables precise control of the pore size of mesoporous carbon thin films, is highly desirable. In this work, we have conducted a series of experiments to control the pore size of mesoporous carbon thin films through thermal and solvent annealing. A well-defined poly(acrylonitrile-b-methyl methacrylate) (PAN-b-PMMA) block copolymer was synthesized using RAFT polymerization and spin-coated into thin films with uniformly spaced globular nanostructures. These globular nanostructures evolved into various morphologies after thermal or solvent annealing. During pyrolysis, when PAN serves as a carbon precursor and can be directly carbonized into mesoporous carbon, PMMA behaves as a sacrificial phase and can be removed easily to create pores. Our research has successfully demonstrated that through thermal annealing and subsequent pyrolysis of PAN-b-PMMA into mesoporous carbon thin films, the pore size and center-to-center spacing increased significantly with thermal annealing temperature (100-300 °C). In addition, we found that the choice of solvent in solvent annealing strongly influenced PAN-b-PMMA nanostructures and the pore size of mesoporous carbon thin films. This work provides a simple strategy to control the pore size of mesoporous carbon thin films by tuning thermal or solvent annealing conditions, instead of synthesizing a series of block copolymers of various molecular weights and compositions.

Controlling the pore size of mesoporous carbon thin films

2019 Spring National Meeting

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