This review introduced polymer-based and polymer composite-based microcellular materials by means of supercritical CO

2

foaming process

and summarized their electromagnetic interference shielding effectiveness (EMI SE)depending on numerous reports composed of the research of ours and others. Various types of polymer systems

including unitary-and multi-thermoplastic polymer systems as well as thermosetting polymer system were reviewed to sum up foamability

cellular morphologies and foams' properties and also to optimize cell parameters (cell size and average cell density) by blending

copolymerization

crystallization and cross-linking and foaming process consideration. And then

thermoplastic and thermosetting polymer matrices modified with carbon nanofillers were foamed by scCO

2

to fabricate corresponding microcellular composite materials

where the interaction between cells and carbon nanofillers was mainly concerned. In foams containing cells and carbon nanofillers

conductive networks are easier formed because the influence of cell growth on nanofillers' redistribution caused them reaggregate and originate along cell walls and thus interconnection. Ultimately

some understandings and perspectives the outstanding electrical conductivity of microcellular composite materials with respect to the development and application of microcellular polymer and polymer/carbon nanofillers materials in the future.