Directional dispersion of ultralong single-walled carbon nanotubes induced by solvent crystallization for effective electromagnetic interference shieldingOA

Single-walled carbon nanotubes(SWCNTs)have promising applications in flexible electromagnetic interference(EMI)shielding materials owing to their electrical and mechanical properties.However,their macroscopic performance has long been constrained by bundle aggregation and processing-induced structural damage.Conventional turbulentbased dispersion methods inevitably trade dispersion efficiency for structural integrity,resulting in a long-standing processing bottleneck.Here,we propose a novel solvent crystallizationinduced directional dispersion(SCIDD)strategy,which engineers a rheological phase transition to couple shear force direction with nanotube debundling orientation.Temperaturecontrolled solvent crystallization along SWCNTs surfaces increases viscosity and drives a turbulent-to-laminar transition,thereby enabling dispersion of ultralong SWCNTs bundles under aligned shear conditions.Computational fluid dynamics and in situ electrical measurements confirm rheological phase transition and flow induced SWCNTs orientation-establishing the mechanistic link between crystallization,rheological phase transition,and non-destructive dispersion.SCIDD has achieved a high-concentration slurry(1 wt.%)that maintains stability for over 10 months,resulting in the production of ultralong SWCNTs(mean aspect ratio~1600;ID/IG=0.012).This significant advancement enables the creation of high-performance freestanding films that exhibit high conductivity(500 S·cm^(-1)),specific shielding effectiveness(SSE/t)up to 47,762 dB·cm^(2)·g^(-1).This work resolves the longstanding efficiency-integrity dilemma in SWCNT processing while offering a scalable,green route to harness the intrinsic properties of one-dimensional nanocarbons for advanced electromagnetic and flexible electronic applications.