Foaming Properties of CO2-Triggered Surfactants for Switchable Foam Control

Switchable surfactants, particularly those triggered by CO2 used for switchable foam control, are relatively less documented. In this article, the foaming performance of 2-alkyl-1-hydroxyethylimidazolinium bicarbonate cationic surfactants (HEAIBs) was investigated for the first time. The foaming properties of these surfactants demonstrate that HEAIBs can generate foam with moderate stability, on demand, can be rapidly yet reversibly dissipated upon exposure to air. The results illustrated such a facile trigger, and the foam on/off transition would have huge potential to form a new class of stimuli-response foaming agents.