Electrostatic Repulsion of Positively Charged Vesicles and Negatively Charged Objects
Helim Aranda-Espinoza,
1*
Yi Chen,
2
Nily Dan,
1*
T. C. Lubensky,
2
Philip Nelson,
2
Laurence Ramos,
3
D.
A. Weitz
2
A positively charged, mixed bilayer vesicle in the presence of
negatively charged surfaces (for example, colloidal particles) can
spontaneously partition into an adhesion zone of definite area and
another zone that repels additional negative objects. Although the
membrane itself has nonnegative charge in the repulsive zone, negative
counterions on the interior of the vesicle spontaneously aggregate
there and present a net negative charge to the exterior. Beyond the
fundamental result that oppositely charged objects can repel, this
mechanism helps to explain recent experiments on surfactant vesicles.
1 Department of Chemical Engineering,
University of Delaware, Newark, DE 19716, USA.
2 Department of Physics and Astronomy, University of
Pennsylvania, Philadelphia, PA 19104 USA.
3 Groupe
de Dynamique des Phases Condensées, Case 26, Université de
Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex 05, France.
*
Address after 1 September 1999: Department of Chemical
Engineering, Drexel University, Philadelphia, PA 19104, USA.
To whom correspondence should be addressed.
Address after 1 September 1999: Department of Physics,
Harvard University, Cambridge, MA 02138, USA.
