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Investigation of liquid diffusion into contact lenses using an electron spin resonance technique
Author(s) -
Özgür Evrim E.,
Aydin Emine,
Özbey Turan,
İrkeç Murat,
Bozkurt Banu,
Kaptan H. Yılmaz
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.22537
Subject(s) - electron paramagnetic resonance , nitroxide mediated radical polymerization , diffusion , spin diffusion , spin probe , spin (aerodynamics) , nuclear magnetic resonance , analytical chemistry (journal) , site directed spin labeling , spectroscopy , chemistry , resonance (particle physics) , materials science , spectral line , atomic physics , physics , polymer , copolymer , thermodynamics , chromatography , radical polymerization , quantum mechanics , astronomy
In this study, electron spin resonance (ESR) spectroscopy was used for the first time to investigate liquid diffusion into contact lenses. As contact lenses are not paramagnetic substances, they were labeled with nitroxide spin probes to get an ESR spectrum. Thus, it gives a solid spin‐labeled ESR spectrum. The shape and intensity of the ESR signals depend on the environment of these spin probes. The spin probe environment began to change from solid to liquid if liquid were dropped into the system. Consequently the ESR spectra began to change with time, too. By following these changes, three distinct steps were found. Their diffusion coefficients were determined to be 6.38 × 10 −8 cm 2 /s for the first step (rapid decay region) and 0.37 × 10 −8 cm 2 /s for the second step (slow decay region), and 2.50 × 10 −8 cm 2 /s for the third and last step (desorption region). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2942–2946, 2006