A novel method to study polymer interfacial dynamics

Colloids and Surfaces, 31 (1988) 265 Elsevier Science Publishers B.V., Amsterdam -

265 Printed in The Netherlands

A Novel Method to Study Polymer Interfacial Dynamics M.A. COHEN STUART and H. TAMAI Agricultural University, Laboratory for Physical and Colloid Chemistry, De Dreijen 6, 6703 BC Wageningen (The Netherlands) (Received 7 September 1987; accepted 11 September 1987)

In Dr Gregory’s paper the statement is made that very little is known about the rate of reconformations of polymer on surfaces. We have recently developed a technique to obtain information on this. The principle of this measurement is to study the streaming potential of a capillary and then injecting polymer into the electrolyte stream in short pulses. The streaming potential essentially gives the hydrodynamic layer thickness, and, hence, one observes, between pulses, the time dependence of the adsorbed layer thickness as it approaches the equilibrium state. The results are indicative of an unfolding going on (10 to several hundreds of seconds) and were found to depend strongly on effective segmental adsorption energy. A schematic diagram showing the polymer concentration pulses as well as the streaming potential response and the corresponding layer thicknesses is shown. Polymer C0”C. 1 linjectedl

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Effect of polymer injected into flowing electrolyte on the streaming potential V, of a glass capillary. Top: Polymer concentration in capillary versus time (schematically). Middle: Streaming potential versus time. Bottom: Adsorbed layer thickness versus time as calculated from V,. 0166-6622/88/$03.50

0 1988 EIsevier Science Publishers B.V.