Sign Switch of Gaussian Bending Modulus for Microemulsions: A Self-Consistent Field Analysis Exploring Scale Invariant Curvature Energies

Ramanathan Varadharajan and Frans A. M. Leermakers
Phys. Rev. Lett. 120, 028003 – Published 10 January 2018
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Abstract

Bending rigidities of tensionless balanced liquid-liquid interfaces as occurring in microemulsions are predicted using self-consistent field theory for molecularly inhomogeneous systems. Considering geometries with scale invariant curvature energies gives unambiguous bending rigidities for systems with fixed chemical potentials: the minimal surface Im3m cubic phase is used to find the Gaussian bending rigidity κ¯, and a torus with Willmore energy W=2π2 allows for direct evaluation of the mean bending modulus κ. Consistent with this, the spherical droplet gives access to 2κ+κ¯. We observe that κ¯ tends to be negative for strong segregation and positive for weak segregation, a finding which is instrumental for understanding phase transitions from a lamellar to a spongelike microemulsion. Invariably, κ remains positive and increases with increasing strength of segregation.

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  • Received 19 July 2017
  • Revised 14 October 2017

DOI:https://doi.org/10.1103/PhysRevLett.120.028003

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Statistical Physics & ThermodynamicsPolymers & Soft Matter

Authors & Affiliations

Ramanathan Varadharajan* and Frans A. M. Leermakers

  • Physical Chemistry and Soft Matter, Wageningen University and Research Center, Stippeneng 4, 6708 WE Wageningen, The Netherlands

  • *Corresponding author. ramanathan.varadharajan@wur.nl
  • frans.leermakers@wur.nl

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Issue

Vol. 120, Iss. 2 — 12 January 2018

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