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Journal of Sensors
Volume 2009, Article ID 703206, 6 pages
http://dx.doi.org/10.1155/2009/703206
Research Article

A Simple Optical Model for the Swelling Evaluation in Polymer Nanocomposites

1Department of Technological and New Materials, Nanomaterials and Devices Technologies Section (FIM MAT-NANO), Research Center ENEA Portici, Piazzale E. Fermi 1, 80055 Portici (NA), Italy
2Technological District on Polymeric and Composite Materials Engineering and Structures IMAST, Piazzale E. Fermi, I-80055 Portici (NA), Italy

Received 31 December 2008; Revised 24 April 2009; Accepted 30 May 2009

Academic Editor: Yongxiang Li

Copyright © 2009 Anna De Girolamo Del Mauro et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In the present study, we report on a simple optical method based on thin film interferometry for the swelling evaluation in polymer nanocomposite layers used for gas sensing applications. We show that white light interferometry can be profitably applied to characterize scattering materials such as polymer/carbon black nanocomposites. A properly adjusted experimental setup was implemented to monitor the swelling behavior of the sensitive films in real device operating conditions. In particular, the behavior of poly(2-hydroxyethyl methacrylate) (PHEMA) and of carbon black/PHEMA nanocomposite layers, used for volatile organic compounds (VOCs) detection, was investigated and measured under ethanol vapors exposure (max 1%). The method is very sensitive and the swelling in the range of only few nanometers can be measured. Interestingly, we have found that the nanocomposite undergoes a more pronounced swelling process with respect to pristine polymer. Ethanol diffusion coefficients in the nanocomposite were evaluated.