%0 Journal Article
%A Poghossian, A.
%A Cherstvy, A. G.
%A Schöning, M. J.
%T Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices.
%J Analytical and bioanalytical chemistry
%V 405
%N 20
%@ 1618-2650
%C Berlin
%I Springer
%M FZJ-2014-00649
%P 6425 - 6436
%D 2013
%X The semiconductor field-effect platform represents a powerful tool for detecting the adsorption and binding of charged macromolecules with direct electrical readout. In this work, a capacitive electrolyte–insulator–semiconductor (EIS) field-effect sensor consisting of an Al-p-Si-SiO2 structure has been applied for real-time in situ electrical monitoring of the layer-by-layer formation of polyelectrolyte (PE) multilayers (PEM). The PEMs were deposited directly onto the SiO2 surface without any precursor layer or drying procedures. Anionic poly(sodium 4-styrene sulfonate) and cationic weak polyelectrolyte poly(allylamine hydrochloride) have been chosen as a model system. The effect of the ionic strength of the solution, polyelectrolyte concentration, number and polarity of the PE layers on the characteristics of the PEM-modified EIS sensors have been studied by means of capacitance–voltage and constant-capacitance methods. In addition, the thickness, surface morphology, roughness and wettabilityof the PE mono- and multilayers have been characterised by ellipsometry, atomic force microscopy and water contact-angle methods, respectively. To explain potential oscillations on the gate surface and signal behaviour of the capacitive field-effect EIS sensor modified with a PEM, a simplified electrostatic model that takes into account the reduced electrostatic screening of PE charges by mobile ions within the PEM has been proposed and discussed.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000321911800005
%R 10.1007/s00216-013-6951-9
%U https://juser.fz-juelich.de/record/150600