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Published online: 6 January 2010 | doi:10.1038/nchina.2009.244

Materials chemistry: Pores breathe new life into polymers

Felix Cheung

Introduction

© (2009) RSC

Poly(ionic liquid)s, or PILs, represent a relatively new class of materials with unique physical and chemical properties that are characteristic of both polymers and ionic liquids. Chemists can tune the properties of a PIL directly by changing the composition of the PIL, and for this reason, PILs are an ideal platform for the development of novel functional materials.

Guangtao Li and co-workers at Tsinghua University in Beijing¹ have now fabricated an imidazolium-based PIL film with an ordered porous structure. The porous structure not only enhances the surface wettability, but also introduces interesting optical properties through interaction of the film with visible light, making the PIL film an extremely useful photonic polymer.

For example, the researchers could change the ion species in the PIL film to cause the porous structure to shrink or swell (pictured top), thereby changing the film colour from red to blue (pictured bottom). The ion response is very fast (~2 min) because the pores are interconnected, and the shrinking–swelling process is completely reversible under the right conditions.

The researchers also found that by exploiting the porous structure, the PIL film could function as a gating system for controlling the flow of water molecules, as well as an electro-optic switch that responds to applied voltage. The introduction of an ordered porous structure greatly extends the functions of PILs. The finding thus demonstrates a useful approach for creating functional PILs-based materials with greater versatility.

The authors of this work are from:
Key Lab of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, China.

Reference

1. Huang, J. et al. 3D-ordered macroporous poly(ionic liquid) films as multifunctional materials. Chem. Commun. doi:10.1039/b921280a (2009). | Article | OpenURL