Research Highlights

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Published online: 23 September 2009 | doi:10.1038/nchina.2009.185

Nanomaterials: Chameleon composites

Anne Pichon

Introduction

© (2009) NPG

Materials that change colour in response to external stimuli offer an attractive solution for sensing applications. Huisheng Peng at Fudan University in Shanghai and co-workers¹ have now prepared a material that changes colour in response to electrical current.

On the one hand, carbon nanotubes (CNTs) are known to be excellent electrical conductors. On the other hand, polydiacetylene (PDA) polymers are known to change colour in response to temperature and pH, and chemical or mechanical stress. The researchers exploited the best of both worlds by creating nanocomposite fibres comprising both CNTs and PDA.

They spun CNTs into fibres, and then coated them with diacetylenic acid precursors. A polymerization step carried out under ultraviolet irradiation then led to highly conductive hybrid CNT–PDA fibres of uniform diameter.

The fibre colour changed rapidly from blue (pictured top) to red (pictured bottom) in response to electrical current. The researchers suggest that this phenomenon may be the result of 'electron hopping' between CNTs within a fibre. The hopping creates an electric field between the CNTs, which affects the electron density and thereby the colour of the PDA.

The nanocomposite fibres also changed colour when exposed to organic vapours and in response to mechanical stress. The researchers believe their invention will find use in a wide range of sensing applications.

The authors of this work are from:
Key Laboratory of Molecular Engineering of Polymers of Ministry of Education, Laboratory of Advanced Materials and Department of Macromolecular Science, Fudan University, Shanghai, China; Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, China; Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California, USA; Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina, USA; Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA.

Reference

1. Peng, H. et al. Electrochromatic carbon nanotube/polydiacetylene nanocomposite fibres. Nature Nanotechnol. doi:10.1038/NNANO.2009.264 (2009). | Article | OpenURL