A New Capacitive Sensor based on Electrostriction Phenomenon. Application for Determination of Ionic Surfactants

AbstractThe aim of the work was to develop a new capacitive sensor based on the electrostriction phenomenon observed in membranes deposited on solid electrodes in contact with an electrolyte solution. The functioning of the sensor was checked in determination of ionic surfactants. The sensor was based on self-assembled monolayers (SAM's) of thiol supported on the surface of a gold electrode. Two thiols, 1-octadecanethiol and 1-hexadecanethiol, and two surfactants, anionic sodium dodecyl sulfate and cationic hexadecyltrimethylammonium bromide, were chosen for studies. Different shapes of capacitance-potential curves with hysteresis were revealed. After an addition of a surfactant, the height of hystheresis changed, enabling construction of linear relationship between the hystheresis’ height and concentration of surfactant