Hostname: page-component-77c89778f8-sh8wx Total loading time: 0 Render date: 2024-07-20T21:58:37.940Z Has data issue: false hasContentIssue false

Characterization and Control of the Wettability of Conducting Polymer Thin Films

Published online by Cambridge University Press:  31 January 2011

Jean H. Chang
Affiliation:
jean_c@mit.edu, Massachusetts Institute of Technology, Mechanical Engineering, Cambridge, Massachusetts, United States
Ian W Hunter
Affiliation:
ihunter@mit.edu, Massachusetts Institute of Technology, Mechanical Engineering, Cambridge, Massachusetts, United States
Get access

Abstract

The wettability of electrochemically deposited conducting polymer films is highly dependent on several parameters including the deposition conditions, the dopant, and the roughness of the working electrode. To produce superhydrophobic surfaces, one must be able to control the micro and nanostructure of the film. In this study, a template-free method of producing superhydrophobic (water contact angle of 154°) polypyrrole films was demonstrated. The polypyrrole was doped with the low surface-energy heptadecafluorooctanesulfonic acid and had microstructures with nanometer-scale roughness. The microstructures served to increase the roughness of the film and amplify the hydrophobicity of the surface. It is also of interest to be able to dynamically adjust the wettability of a polypyrrole surface after deposition. Applications of this functionality include microfluidics, self-cleaning surfaces, liquid lenses, and smart textiles. By oxidizing or reducing a polypyrrole film, one can change the surface morphology as well as the chemical composition, and control the wettability of the surface. This study characterizes the electrochemically-induced changes in surface energy of polypyrrole. The relationship between applied voltage, charge transferred, surface roughness, and water contact angle was investigated. Upon reduction, the polypyrrole film was switched to a superhydrophilic state and the maximum change in contact angle was observed to be 154°. Surface wettability was found to be not fully reversible, with some hysteresis occurring after the first electrochemical cycle.

Type
Research Article
Copyright
Copyright © Materials Research Society 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Madden, J. D.. Conducting Polymer Actuators. PhD Thesis, Massachusetts Institute of Technology, 2000.Google Scholar
2 Pytel, R.. Artificial Muscle Morphology: Structure/Property Relationships in Polypyrrole Actuators. PhD Thesis, Massachusetts Institute of Technology, 2007.Google Scholar
3 Wong, J.Y. Langer, R.L. and Ingber, D.E. Proc. Nat. Acad. Sci. USA 91, 3201 (1994).Google Scholar
4 Ateh, D.D. Navsaria, H.A. and Vadgama, P. J. R. Soc. Interface 3, 741 (2006).Google Scholar
5 Wan, M. Advanced Materials 20, 2926 (2008).Google Scholar
6 Gennes, P. de, Brochard-Wyart, F., and Quérè, D., in Capillarity and Wetting Phenomena: Drops, Bubbles, Pearls, Waves, translated by Reisinger, A. (Springer-Verlag, New York, 2004).Google Scholar
7 Gao, L. and McCarthy, T.J. Langmuir 22, 2966 (2006).Google Scholar
8 Halldorsson, J.A. Little, S.J. Diamond, D. Spinks, G. and Wallace, G. Langmuir 25, 11137 (2009).Google Scholar
9 Wang, X. Berggren, M. and Inganaes, O. Langmuir 24, 5942 (2008).Google Scholar
10 Wang, X. Tvingstedt, K. and Inganaes, O. Nanotechnology 16, 437 (2005).Google Scholar
11 Lee, W. Jin, M.K. Yoo, W.C. and Lee, J.K. Langmuir 20, 7665 (2004).Google Scholar
12 Xu, L. Wang, J. Song, Y. Jiang, L. Chemistry of Materials 20, 3554 (2008).Google Scholar
13 Xu, L. Chen, W. Mulchandani, A. Yan, Y. Angew. Chem. Int. Ed. 44, 6009 (2005).Google Scholar
14 Wiedenman, N.. Towards Programmable Materials- Tunable Material Properties Through Feedback Control of Conducting Polymers. PhD Thesis, Massachusetts Institute of Technology, 2008.Google Scholar