Poly(ethylene oxide)-silica hybrids entrapping sensitive dyes for biomedical optical pH sensors: Molecular dynamics and optical response

Paola Fabbri, Francesco Pilati, Luigi Rovati, Ruel McKenzie, Jovan Mijovic

Research output: Contribution to journalArticlepeer-review

Abstract

Polymer-silica hybrid nanocomposites prepared by sol-gel process based on triethoxisilane-terminated poly(ethylene oxide) chains and tetraethoxysilane as silica precursor, doped with organic pH sensitive dyes, have been prepared and their suitability for use as sensors coupled with plastic optic fibers has been evaluated. Sensors were prepared by immobilizing a drop of the hybrid materials onto the tip of a multi-mode poly(methyl methacrylate) optical fiber. The performance of the optical sensor in terms of sensitivity and response time was tested in different experimental conditions, and was found to be markedly higher than analogous sensors present on the market. The very fast kinetic of the hybrid's optical response was supported by studies performed at the molecular level by broadband dielectric relaxation spectroscopy (DRS), investigated over a wide range of frequency and temperature, showing that poly(ethylene oxide) chains maintain their dynamics even when covalently bonded to silica domains, which decrease the self-association interactions and promote motions of polymer chain segments. Due to the fast response kinetic observed, these pH optical sensors result suitable for the fast-detection of biomedical parameters, i.e. fast esophageous pH-metry.

Original languageEnglish (US)
Pages (from-to)1362-1369
Number of pages8
JournalOptical Materials
Volume33
Issue number8
DOIs
StatePublished - Jun 2011

Keywords

  • Dielectric relaxation spectroscopy
  • Plastic optical fiber
  • Polymer-silica hybrids
  • Sol-gel
  • pH sensor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Computer Science(all)
  • Atomic and Molecular Physics, and Optics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Electrical and Electronic Engineering

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