A Designed Biosurfactant Protein for Switchable Foam Control

Abstract

Making and breaking foams: A facile method for foam control is reported using a designed biosurfactant. The new biosurfactant is based on a four-helix bundle design which is interfacially active across a broad pH range. At pH 8.5 stable foam forms, yet decreasing the pH to 7.5 causes rapid foam dissipation. This unique behaviour can be linked to subtle molecular and specific-ion effects which lead to switchable changes in the state of the foam thin film (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.