ORIGINAL RESEARCH
Investigation of Copper and Manganese Ion
Diffusion through Hydrogel Contact Lens
Materials Using ESR Technique
Katarzyna Krysztofiak, Andrzej Szyczewski, Zdzisław Kruczyński
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Division of Medical Physics, Department of Physics, A. Mickiewicz University in Poznań,
Umultowska 85, 61-614 Poznań, Poland
Pol. J. Environ. Stud. 2014;23(2):363-371
KEYWORDS
ABSTRACT
Diffusion of tear film components through a hydrogel contact lens is significantly influenced by its interactions
with material. In our study Cu2+ and Mn2+ ions were used to describe transport properties of the membranes
which were hydrogel contact lens materials. Ion concentrations were measured by an electron spin resonance
(ESR) spectrometer, and differential scanning calorimetry (DSC) was used as a complementary technique.
The materials investigated were nelfilcon A and etafilcon A. Diffusion D and permeation P coefficients
were calculated. In both materials transport dynamics can be described by two stages (except for CuSO4 in
etafilcon A), where the first is shorter and characterized by higher diffusion D and permeation P coefficients
than the second one. The results obtained allowed us to make conclusions about the interactions between the
ions and polymer chains that may happen inside the hydrogel matrix during diffusion, affecting transport
dynamics.