High-Concentration Aqueous Carbon Nanotube Dispersions

Aqueous carbon nanotube (CNT) dispersions stabilized by surfactants are emerging as safe and eco-friendly approaches for fabricating CNT assemblies. However, obtaining liquid-crystalline (LC) CNT dispersions in processable quantities remains challenging and is critical for the full utilization of their exceptional properties. In this paper, we present a scalable and facile method for concentrating surfactant-assisted aqueous CNT dispersions using superabsorbent polymer (SAP) beads, inspired by the hydration behavior of chia seeds. SAP beads selectively absorb water and surfactants while excluding CNTs, enabling SAP-induced dialysis (SPID). The CNT dispersions were concentrated 12-fold (from 0.4 to 4.79 wt %), accompanied by spontaneous transitions from the isotropic to the LC phase and from the sol to the gel phase. The SPID process enables the demonstration of potential applications, such as electrically conducting liquids for flexible sensors, wet-spinning LC dope, and CNT aerogel precursors, broadening the possibilities for the solution processing of surfactant-assisted CNT dispersions.