Supercritical CO2-Processed Polymeric Foams for Process Intensification Structure, Functionality, and Advanced Applications

Polymeric materials foamed using supercritical carbon dioxide (scCO2) offer a sustainable and versatile basis for developing advanced porous structures with highly adjustable morphology, density, and functionality. This chapter provides a comprehensive overview of the physical principles and processing strategies involved in generating foams with hierarchical porosities, emphasizing their potential for process intensification. The correlations between structure and functionality are presented and illustrated using case studies in which porosity values of over 90%, open-cell contents of up to 96%, and functional loads of over 18% are achieved in scCO2-assisted impregnation processes. The advantages of this technology for the in-situ formation of catalysts are analyzed, demonstrating increases in hydrogen production of up to ~60% compared to traditional packed beds. Integrating functional impregnation and foaming in a single step, together with using a clean, recyclable physical agent such as scCO2, makes these foams ideal for advanced applications in compact reactors, controlled release systems and biomedical platforms. The combination of sustainability, multiscale morphological control and multifunctional properties establishes these foams as essential components in the development of more efficient, intensified, and environmentally responsible emerging technologies.