High dielectric PANI/PDMS all-organic composites fabricated by electric fields-assisted assembling

Here, we demonstrate a simple and scalable approach of assembling the polyaniline (PANI) particles in polydimethylsiloxane (PDMS) matrix assisted by an external AC electric field. The PANI particles were polarized and assembled into a network structure along the field direction (out-of-plane). Compared to random oriented control samples, the network structure formed by PANI particles significantly increases the dielectric permittivity of the composite material, while the dielectric loss still remains at a relatively low value (0.439 for 10wt% PANI/PDMS, 102 Hz). In this work, the PANI structural rearrangement mechanism and its assembly kinetics under the electric field are revealed through in situ optical imaging. Specifically, by adding 10 wt% of PANI particles, the dielectric permittivity of the electric-field-assembled PANI/PDMS composite reaches up to 99.4, which is 30 times higher than pristine PDMS (3.38), and 20 times higher than the random dispersed counterpart (5.1). Additionally, PANI networks can improve the ability of composite for electromagnetic shielding application, which has been systemically investigated. We believe that our work provides a facile and promising strategy to fabricate functional composites with rationally designed network structures through the application of electric field, which can have broad applications such as sensors and multifunctional electromagnetic shielding.