Solvent-Chirality-Gated Recognition of Carbon Nanotubes by Polysaccharides

Chiral molecular recognition is typically achieved through static complementarity between chiral hosts and molecular guests. Dynamic control of such recognition through external stimuli remains an important challenge, particularly for interactions involving extended solid surfaces. Here we show that solvent chirality can act as an external control parameter that modulates the conformation of polysaccharide dispersants and thereby creates a tunable chiral recognition field for one-dimensional nanomaterials. By continuously varying the enantiomeric excess of chiral solvents, the conformation of cellulose acetate can be modulated, resulting in switchable selectivity in the extraction of semiconducting single-walled carbon nanotubes (SWCNTs). Spectroscopic and structural analyses reveal that solvent chirality alters the balance between inter- and intramolecular interactions within the polysaccharide, leading to distinct conformational states that influence nanotube recognition. These findings demonstrate that chiral solvation can dynamically modulate macromolecular recognition fields and provide a strategy for controlling interactions between soft matter and extended solid nanostructures.