Electrically conductive microcellular foams via high internal phase emulsions

Abstract

Emulsion-based microcellular foams offer several advantages over conventional extruded foams, including small cell size, open cell structure, and various functionalities. To transform emulsions into polymer foams, a high internal phase emulsion must be formed in which the monomer-based oil phase acts as the continuous phase and the aqueous phase with a very high volume fraction is the dispersed phase, and the cell structure must be maintained during the polymerization process. Electrically conductive foams are fabricated by incorporating conductive fillers or additives, and these materials need to be designed so as not to affect the stability of the emulsion. The key to successful emulsion-based functional foams lies in achieving a synergistic combination of the inherent advantages of the emulsion and the specific roles of functional additives. In this mini-review, we discuss the characteristics of high internal phase emulsions and foams obtained by polymerizing such emulsions, and then discuss the preparation, morphology, and properties of electrically conductive emulsion-based foams. We also explore the development trends of carbonized polymer foams and investigate methods to achieve optimal performance as electrically conductive materials.