Eur. Phys. J. E 7, 241-250 (2002)
Hyperviscous diblock copolymer vesiclesR. Dimova1, 2, U. Seifert1, 3, B. Pouligny2, S. Förster4 and H.-G. Döbereiner1
1 Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14476 Golm, Germany
2 Centre de Recherche Paul Pascal, CNRS, Pessac 33600, France
3 Universität Stuttgart, Institut für Theoretische Physik II, Pfaffenwaldring 57, 70550 Stuttgart, Germany
4 Universität Hamburg, Institut für Physikalische Chemie, Bundesstraße 45, 20145 Hamburg, Germany
(Received 2 March 2001 and Received in final form 15 February 2002)
Giant vesicles prepared from the diblock copolymer polybutadien-b-polyethyleneoxide (PB-PEO) exhibit a shear surface viscosity, which is about 500 times higher than those found in common phospholipid bilayers. Our result constitutes the first direct measurement of the shear surface viscosity of such polymersomes. At the same time, we measure bending and stretching elastic constants, which fall in the range of values typical for lipid membranes. Pulling out a tether from an immobilized polymersome and following its relaxation back to the vesicle body provides an estimate of the viscous coupling between the two monolayers composing the polymer membrane. The detected intermonolayer friction is about an order of magnitude higher than the characteristic one for phospholipid membranes. Polymersomes are tough vesicles with a high lysis tension. This, together with their robust rheological properties, makes them interesting candidates for a number of technological applications.
83.50.Lh - Slip boundary effects (interfacial and free surface flows).
83.85.Jn - Viscosity measurements.
87.16.Dg - Membranes, bilayers, and vesicles.
87.80.Cc - Optical trapping.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002