Monolayers of poly-L-lysine on mica--Electrokinetic characteristics.
Physicochemical properties of poly-l-lysine and its monolayers on mica were thoroughly investigated by dynamic light scattering, electrokinetic methods and atomic force microscopy. The hydrodynamic diameter of PLL was equal to 25.5 nm within a wide range of pH and ionic strength. The electrophoretic measurements revealed that the molecules are positively charged for pH<10.5. By exploiting the electrophoretic mobility data, theelectrokinetic charge on the PLL molecules and their zeta potential were calculated. PLL monolayers of controlled coverage were deposited on mica under diffusion-controlled conditions by varying PLL bulk concentration and adsorption time. The electrokinetic characteristics of the monolayers were acquired in situ via streaming potential measurements. These studies allowed to uniquely determine the zeta potential of the monolayers as a function of pH and ionic strength. In this way the isoelectric point of the monolayers can be determined in a more convenient way compared to bulk measurements disturbed by the PLL molecule interactions. The stability of the monolayers under flow conditions was quantitatively evaluated via streaming potential measurements. The adsorption constant and the binding energy depth of PLL molecules were determined for different ionic strengths. These parameters indicate that the PLL monolayers remain stable over prolonged times.
['Morga|Maria|M|', 'Adamczyk|Zbigniew|Z|', 'Gödrich|Sebastian|S|', 'Oćwieja|Magdalena|M|', 'Papastavrou|Georg|G|']
D000327:Adsorption D000538:Aluminum Silicates D004563:Electrochemistry D004573:Electrolytes D004867:Equipment Design D057446:Hydrodynamics D006863:Hydrogen-Ion Concentration D007700:Kinetics D008027:Light D018625:Microscopy, Atomic Force D009994:Osmolar Concentration D011107:Polylysine D012542:Scattering, Radiation D013499:Surface Properties D013997:Time Factors D014783:Viscosity
Adsorption of poly-l-lysine on mica Electrokinetic characteristics of poly-l-lysine molecules Electrokinetics of poly-l-lysine monolayers Poly-l-lysine monolayers at mica Stability of poly-l-lysine monolayers at mica Zeta potential of poly-l-lysine monolayers at mica