Polyethyleneimine as a pH sensitive film for potentiometric transducers

The anodic oxidation of ethylenediamine (EDA) leads to the formation of pol yethyleneimine (PEI) as a pH sensitive thin film on conducting and semi-con ducting electrode surfaces. The passivated electrodes exhibit a sub-nerstia n response which depends strongly on the electrode material. In particular, the PEI-coated silicon electrodes present a linear pH sensitivity close to 50 mV per pH unit over a large pH range. This response could be fitted wit h the site-binding model applied to the acido-basic equilibrium of amino gr oups present at PEI/electrolyte interface. (C) 2001 Elsevier Science B.V. A ll rights reserved.