Bubble dynamics manipulation in polymeric foaming†

Abstract

The release of pressure from a high-pressure-stable polymer/gas solution is a common method for creating gas bubbles and forming foam with a typical polyhedral cell structure. We propose a new approach to control the foaming process by pausing the bubble growth at intermediate pressure before reaching ambient pressure. This allows us to control the growth of the bubbles and investigate various physical phenomena involved in polymer foaming, such as Ostwald ripening, bubble interactions, coalescence, and different bubble growth regimes. We conducted these studies in a model system PP/N₂ by subjecting the solution to non trivial pressure histories. Our method will have an impact on the study of fundamental phenomena involved in foaming and their application in creating new materials.