Reply to Comment on "Faceting and flattening of emulsion droplets: a mechanical model" by Haas et al

TL;DR

This paper refutes hypotheses suggesting different physical mechanisms or mathematical equivalence of models explaining shape transformations in surfactant-stabilized emulsion droplets, emphasizing the need for accurate interpretation of experimental and theoretical results.

Contribution

It clarifies that the hypotheses proposed by Haas et al. are not well justified, reinforcing the validity of existing models for droplet shape transformations.

Findings

Haas et al.'s hypotheses are not supported

Existing models remain valid for shape transformations

Physical mechanisms may be consistent despite different surfactants

Abstract

In their Comment [arXiv:2102.03842], Haas et al. advance two hypotheses on the nature of the shape transformations observed in surfactant-stabilized emulsion droplets, as the theoretical models that us [Phys. Rev. Lett. 126, 038001 (2021)] and others [P. A. Haas et al. Phys. Rev. Lett. 118, 088001 (2017), Phys. Rev. Research 1, 023017 (2019)] have introduced to account for these observations. (1) Because of the different surfactants used in experimental studies, the physical mechanisms underpinning the shape transformations may, in fact, differ in spite of the extraordinary resemblance in the output. (2) The theoretical models are mathematically equivalent by virtue of the small magnitude of the stretching and gravitational energies. In this Reply, we argue that neither of these hypotheses is well justified.