Ion transport through polyelectrolyte multilayers

Polyelectrolyte multilayer (PEM) fi lms and capsules loaded with ion-sensitive fl uorophores can be used as ion-sensors for many applications including measurements of intracellular ion concentration. Previous studies have shown the infl uence of the PEM fi lms/shells on the specifi c response of encapsulated ion-sensitive fl uorophores. PEM shells are considered as semipermeable barriers between the environment and the encapsulated fl uorophores. Parameters such as the time response of the encapsulated sensor can be affected by the porosity and charge of the PEM shell. In this study, the time response of an encapsulated pH-sensitive fl uorophore towards pH changes in the surrounding environment is investigated. Furthermore, the conductance of PEM fi lms for potassium ions is determined.