Dispersion of carbon nanotubes triggered by the helical self-assembly of poly(methyl methacrylate)

Single-walled carbon nanotubes (SWCNTs) are promising nanofillers for various advanced materials, but their uniform dispersion in commodity plastics remains elusive due to solubility problems and poor miscibility. Here, we demonstrate that poly(methyl methacrylate) (PMMA) acts as an effective surfactant for the selective dispersion of small-diameter SWCNTs under θ-solvent conditions. The solvent quality critically governs the formation of PMMA hierarchical helical structures, which enables efficient SWCNT encapsulation. Furthermore, we find that the stereoregularity of PMMA, in particular the syndiotacticity, controls the dispersion selectivity based on the nanotube diameter. The combination of experimental studies and DFT calculations reveals that the dynamic helical conformations of PMMA create nanoscale cavities that are conducive to the entrapment of SWCNTs. This work provides important insights into the design of polymer-nanotube hybrids and opens new avenues for the use of commodity plastics in advanced nanocomposites.