Bubble nucleation in the surfactant stabilized polyol-CO₂ mixtures: Insights from a classical density function theory study

Silicone-polyether (SPE) surfactants, made of poly dimethyl-siloxane backbone and polyether branches, are commonly used to stabilize the polyol-CO₂ foam formulation. The  SPE surfactants reduce interfacial tension between polyol-CO₂ interface_, promote bubble generation and impacts the foam cell size. However, the mechanism through which SPE surfactants affect the nucleation and stability of the bubbles is not well understood. We find that increase in the CO₂ concentration  in the polyol+CO₂+SPE system leads to significant decrease in the SPE CMC. This underscores the importance of CO₂ bubble nucleation from a pre-formed micelle. In this work using classical density functional theory we will compare and contrast our observations on the CO₂ bubble nucleation from a homogeneous polyol+CO₂+SPE mixture and from a preformed SPE micelle in the system.