This research compares the mass transport and ion-exchange properties of two hydrophobically modified micellar polymers, chitosan and Nation. It was shown that hydrophobically modified micellar polymers alter the transport properties of redox species to the electrode surface as a function of the size and charge of the redox species. This research details the first use of hydrophobically modified chitosan to modify electrode surfaces, along with evidence that oxidoreductase enzymes can be effectively immobilized in the polymers while maintaining enzymatic activity. Glucose oxidase was immobilized within the hydrophobically modified chitosan and the resulting enzyme activity was compared to buffer measurements and immobilization within hydrophobically modified Nation. It was shown that the increase in hydrophobicity increases the enzyme activity, resulting in a more optimal membrane for enzyme immobilization. (c) 2006 Elsevier B.V. All rights reserved.