Surface modification of single-walled carbon nanotubes with deep eutectic solvents: toward stable nanocarriers

چکیده مقاله

Single-walled carbon nanotubes (CNTs) are promising nanocarriers for advanced drug-delivery systems, but their practical application is limited by poor dispersion and strong aggregation in aqueous and biological environments. This study explores choline chloride-based deep eutectic solvents (DESs) as sustainable media for improving CNT dispersion and stability. DES formation and thermal behavior were characterized by Fourier-transform infrared spectroscopy and thermogravimetric analysis, while DES-induced CNT surface modification was examined using FTIR, X-ray diffraction, and Raman spectroscopy. CNT dispersion and dynamic stability in seven DES formulations were then evaluated by UV–Vis spectroscopy and molecular dynamics simulations, with water used as a reference medium. All DESs substantially enhanced CNT dispersion relative to water. Choline chloride/malonic acid showed the strongest effect, producing a 21-fold increase in CNT dispersion, followed by choline chloride/tartaric acid with a 19-fold enhancement. The improved behavior was attributed to favorable DES–CNT interactions and extended hydrogen-bonding networks that reduced nanotube aggregation and stabilized dispersed CNTs. Molecular dynamics simulations further confirmed persistent interactions between DES components and CNT surfaces. These findings demonstrate that choline chloride-based DESs are tunable, environmentally benign platforms for CNT dispersion and surface modification, with potential utility in advanced drug-delivery and nanomedicine applications, and other future biomedical nanotechnology applications.