Highly efficient electromagnetic interference shielding and superior mechanical performance of carbon nanotube/polydimethylsiloxane composite with interface-reinforced segregated structure

The formation of segregated structure in conductive polymer composite is an effective strategy to improve electromagnetic interference (EMI) shielding performance. However, inferior mechanical properties always existed in the segregated composite due to weak interfacial adherence or defects. Herein, an interface-reinforced segregated structure was constructed in a carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite by creating chemical bonds between PDMS microcells and the continuous PDMS interfacial phase embedded with CNT. The interface-reinforced segregated composites achieved the integration of excellent EMI shielding and good mechanical properties. Specifically, the resultant composite exhibited a superior EMI shielding effectiveness (EMI SE) of 47.0 dB at only 2.2 vol% CNT content. The tensile strength and elongation at break of the composite were 3.6 MPa and 87.0%, increased by 35.0 and 7.0 times in comparison to the conventional segregated composite. The interface-reinforced segregated composite also demonstrated excellent reliability with high EMI SE retention of 80% even after suffering from 1000 stretching-releasing cycles at a terminal strain of 30%. This work provides an important guideline for the development of high-performance polymer composite with efficient EMI shielding and good mechanical performances.