TY  - JOUR
A1  - Poghossian, A.
A1  - Weil, M.
A1  - Cherstvy, Andrey G.
A1  - Schöning, M. J.
T1  - Electrical monitoring of polyelectrolyte multilayer formation by means of capacitive field-effect devices
JF  - Analytical & bioanalytical chemistry
N2  - 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.
KW  - Field-effect
KW  - Capacitive sensor
KW  - Polyelectrolyte multilayer
KW  - Electrical monitoring
KW  - ConCap
Y1  - 2013
U6  - https://doi.org/10.1007/s00216-013-6951-9
SN  - 1618-2642
VL  - 405
IS  - 20
SP  - 6425
EP  - 6436
PB  - Springer
CY  - Heidelberg
ER  -