# Surfactant films in lyotropic lamellar (and related) phases: Fluctuations and interactions

## TL;DR

This paper explores the analogy between soap film thinning and lamellar surfactant phases, focusing on fluctuations, interactions, and the transition to Newton black films under dehydration.

## Contribution

It provides a comparative analysis of surfactant film behavior and lamellar phases, highlighting the nature of short-range interactions and fluctuations in highly dehydrated states.

## Key findings

- Short-range repulsive interactions are key in film stability.
- The transition to Newton black films involves specific fluctuation behaviors.
- Analogies between soap films and lamellar phases enhance understanding of surfactant systems.

## Abstract

The analogy between soap films thinning under border capillary suction and lamellar stacks of surfactant bilayers dehydrated by osmotic stress is explored, in particular in the highly dehydrated limit where the soap film becomes a Newton black film. The nature of short-range repulsive interactions between surfactant-covered interfaces and acting across water channels in both cases will be discussed.