Multifunctional polyether block amides/carbon nanostructures piezoresistive foams with largely linear range, enhanced and humidity-regulated microwave shielding

•The highly porous and multifunctional elastomer foam was prepared via ScCO2 blowing.•PEBA/CNS composites were foamed successfully above melt temperature of PEBA.•The foams exhibited enhanced and humidity-regulated EMI shielding.•The sensor had a large linear range up to 70% strain, long lifetime and good repeatability.•The foams had great prospects in monitoring human motion and health protection.