Organic Droplets at an Electrified Interface: Critical Potentials of Wetting Measured by Polarography

Probing cell surface charge by scanning electrode potential

“…Excellent agreement was obtained for critical interfacial tension of wetting determined from potentials of microdroplet adhesion at DME [11,12] and the prediction based on the Good-Girifalco-Fowkes equation [13]. Excellent agreement was obtained for critical interfacial tension of wetting determined from potentials of microdroplet adhesion at DME [11,12] and the prediction based on the Good-Girifalco-Fowkes equation [13].…”

In Situ Amperometric Characterization of Liposome Suspensions with Concomitant Oxygen Reduction

“…Based on amperometrically measured critical potentials of adhesion and electrocapillary data, critical interfacial tensions of adhesion at the positively (g 12 could be attributed to electrostatic interaction between liposome and mercury interface. In contrast, critical interfacial tensions of adhesion are equal at the positively and negatively charged electrode for non-polar liquids, pointing to the importance of dispersion forces in hydrocarbon interaction with mercury and water interface [6,33]. Minimum signal frequency was shifted negatively by 82 mV from the E pzc , i.e., to the potential of À 584 mV.…”

“…The critical potentials of adhesion were determined to be À 100 mV and À 1200 mV (Fig. 5A), which correspond to the most negative and to the most positive potentials where at least one adhesion signal is recorded per 10 consecutive I -t curves [4,6]. At the potentials positive to À 100 mV and negative to À 1200 mV, adhesion signals of liposomes were not detected and liposomes behave as inert particles.…”

“…By potentiostatic control of surface charge and tension, adhesion forces can be fine tuned to study the interplay of complex forces involved in surfaceactive particles (vesicles, microdroplets and cells)/electrode double-layer interactions [4,5]. During their attachment and spreading at the charged interface, surface-active particles displace the double-layer charge from the inner Helmholtz plane, and the transient flow of compensating current can be recorded as an electrical adhesion signal [4,6,7]. After the studies of adhesion signals of non-polar hydrocarbon droplets and of negatively charged living cells [7 -10] we focused here on lipid vesicles (liposomes), the classical model for studying physical mechanisms of cell adhesion [11].…”

Mathematical model for kinetics of organic particle adhesion at an electrified interface

“…During adhesion and spreading, organic particles displace double-layer charge from the inner Helmholtz plane at the mercury/aqueous electrolyte interface, and transient flow of compensating current is recorded as a well-defined adhesion signal [4] (the so-called current transient). Current transients of organic droplets, living cells and liposomes were used to investigate thermodynamics and kinetics of such an event [4][5][6][7][8][9][10][11][12][13][14] in order to understand particle aggregation in aquatic system. Bizzotto and coworkers studied the interaction of liposomes from aqueous suspension with mercury electrode, and characterization of layers formed has been extensively performed by using electrochemical and optical techniques [15][16][17].…”