Composite phase change materials embedded into cellulose/polyacrylamide/graphene nanosheets/silver nanowire hybrid aerogels simultaneously with effective thermal management and anisotropic electromagnetic interference shielding

Abstract

Exploiting an advanced material simultaneously with effective thermal management (TM) and electromagnetic interference (EMI) shielding capacity is ungently demanded yet challenging for the miniaturized and integrated electronics. Anisotropic networks can be impregnated with phase change materials (PCMs) to fabricate multifunctional shape-stable PCMs (ss-CPCMs) simultaneously with excellent TM and EMI shielding, which is rarely reported. Herein, the anisotropic cellulose/polyacrylamide/graphene nanosheet/silver nanowire (CPGxAy) hybrid aerogels were successfully prepared using directional freeze-drying method, and then utilized as supporting skeletons to embed polyethylene glycol (PEG) via vacuum-assistant impregnation. Profited by the synergistic effect of graphene nanosheets (GNPs) and silver nanowires (AgNWs), the resultant polyethylene glycol@cellulose/polyacrylamide/graphene nanosheet/silver nanowire hybrid aerogel (PEG@CPGxAy) ss-CPCMs exhibit fascinating thermal conductivity (TC) of 0.84 W/m·K (200% increase in comparison with that of pure PEG) and anisotropic average EMI shielding effectiveness (SE) of 71.08 dB along the transverse direction and 35.21 dB along the longitudinal direction, while remaining high melting and crystallization enthalpy efficiency of 93.47% and 93.08%, respectively. In addition, PEG@CPGxAy ss-CPCMs also display great shape stability, thermal stability, and cyclic reusability in the storing/releasing latent heat processes. This investigation sheds new light on designing and fabricating ss-CPCMs with pretty comprehensive properties for TM and EMI shielding of modern electronics.Graphical Abstract