Stretchable PEDOT:PSS/Li-TFSI/XSB Composite Films for Electromagnetic Interference Shielding

Electromagnetic interference (EMI) shielding materials with stretchability are important for developing wearable and flexible appliances. Herein, lithium bis(trifloromethanesulfonyl)imide (Li-TFSI)-doped poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and carboxylated styrene-butadiene rubber (XSB) latex are used to prepare stretchable EMI shielding composite films of 0.2 mm in thickness. In these films, the doped PEDOT:PSS nanoparticles form tenuous conductive pathways between the hexagonally packed latex particles, resulting in higher EMI shielding efficiency (EMI SE) compared with the films containing traditional dopant ethylene glycol. For the purpose of stretchable EMI shielding, the films containing 6 wt % PEDOT:PSS and 6 wt % Li-TFSI demonstrate EMI SE of 50 and 30 dB (12.4 GHz) at 0 and 100% strains, respectively, being the highest values among the reported shielding composites except for those using liquid metal as the filler. The investigation also provides a simple and environmentally friendly preparation method being highlighted for the development of lightweight stretchable EMI shielding materials for applications in flexible electronics in the near future.