A potentiostatic study of oxygen transmissibility and permeability throughhydrogel membranes

The permeability characteristics of membranes prepared from hydrogels of po ly(2-hydroxyethylmethacrylate) (PHEMA) and poly(2-hydroxyethylmethacrylate- co-N, N-dimethylacrylamide) (PHNDA) are described. True values of the perme ability and transmissibility coefficients of oxygen in the membranes are de termined by using electrochemical procedures involving the measurement of t he steady state current either in membranes with different thickness or ina single membrane in which its thickness is varied with layers of moistened paper. Comparison of the results obtained for the transport properties in t hese hydrogels with others obtained in other hydrogels permit to conclude t hat the degree of swelling rather than the chemical nature of the hydrogels affects the permeation properties. The chemical structure presumably only affects in high degree the chemical stability and flexibility of the hydrog el membranes. (C) 1998 Published by Elsevier Science Ltd. All rights reserv ed.