DOI: 10.1051/jp2:1994227
J. Phys. II France 4 (1994) 1713-1725

Membrane-induced interactions between inclusions

N. Dan¹, A. Berman², P. Pincus³ and S. A. Safran<sup>1

1</sup>  Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
²  Department of Chemical and Nuclear Engineering, University of California, Santa Barbara CA 93106-5080, U.S.A.
³  Departments of Materials and Physics, University of California, Santa Barbara CA 93106-5080, U.S.A.

(Received 15 May 1994, accepted 8 Iuly 1994)

Abstract
We investigate theoretically the effect of embedded inclusions on membrane structure, and the corresponding membrane-induced interactions between inclusions. We find that the membrane thickness, which is perturbed from its equilibrium value by the coupling to the embedded inclusions, decays non-monotonically with distance from the inclusion boundary. As a result, the membrane-induced interactions between inclusions vary non monotonically with spacing. The periodicity of the perturbation profile, as well as the strength and range of the induced interactions, are proportional to the ratio of the amphiphile bending modulus and compressibility. In systems where the inclusions impose a thickness-matching constraint, the induced interactions are attractive. However, the presence of an energy barrier at a finite spacing may hinder aggregation. In systems where the inclusions impose a specific contact-angle, the interaction energy is minimal at a finite inclusion spacing.

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