Highly‐Selective Harvesting of (6,4) SWCNTs Using the Aqueous Two‐Phase Extraction Method and Nonionic Surfactants

Abstract

Monochiral single‐walled carbon nanotubes (SWCNTs) are indispensable for advancing the technology readiness level of nanocarbon‐based concepts. In recent times, many separation techniques have been developed to obtain specific SWCNTs from raw unsorted materials to catalyze the development in this area. This work presents how the aqueous two‐phase extraction (ATPE) method can be enhanced for the straightforward isolation of (6,4) SWCNTs in one step. Introducing nonionic surfactant into the typically employed mixture of anionic surfactants, which drive the partitioning, is essential to increasing the ATPE system's resolution. A thorough analysis of the parameter space by experiments and modeling reveals the underlying interactions between SWCNTs, surfactants, and phase‐forming agents, which drive the partitioning. Based on new insight gained on this front, a separation mechanism is proposed. Notably, the developed method is highly robust, which is proven by isolating (6,4) SWCNTs from several raw SWCNT materials, including SWCNT waste generated over the years in the laboratory.

Sorting of Carbon Nanotubes Based on Dispersant Binding Affinities

“…[ 185 ] In addition, single‐chirality separation has been achieved with just one extraction step by introducing polymers [ 191 ] and nonionic dispersants. [ 192 ] Furthermore, a new separation technique [ 193 ] has been recently proposed, achieving single chirality separation by extracting the single chirality, initially extracted by the water system, into an organic system with PFO dispersant. However, its disadvantage is that it is a repetitive and continuous separation process whose the concentration of the medium polymer and the dispersant must be carefully controlled.…”

“…[185] In addition, single-chirality separation has been achieved with just one extraction step by introducing polymers [191] and nonionic dispersants. [192] Figure 16. GCC-based sorting of SWNTs according to type and handedness.…”

Understanding the Molecular Assemblies of Single Walled Carbon Nanotubes and Tailoring their Photoluminescence for the Next-Generation Optical Nanosensors

“…106−108 Through meticulous manipulation of the polymer concentration and extraction conditions, chirality sorted SWCNTs can be extracted. 108 Unlike ion-exchange and density-gradient methods, the ATPE method is relatively more scalable and requires less sophisticated instrumentations. Chirality-pure SWCNTs 109 can be functionalized with the ATPE approach by attaching targeting moieties such as antibodies, oligonucleotides, and polymers to create sensors that produce nonoverlapping signals, providing notable benefits compared to conventional sensing methods.…”

“… ATPE utilizes the distinct solubility of SWCNTs in two separate aqueous phases, typically formed by combining polymers such as dextran and polyethylene glycol (PEG) dissolved in water . SWCNTs’ dispersion among these phases is affected by their chirality and interactions with surfactants, enabling the separation of particular ( n , m ) SWCNTs. − Through meticulous manipulation of the polymer concentration and extraction conditions, chirality sorted SWCNTs can be extracted . Unlike ion-exchange and density-gradient methods, the ATPE method is relatively more scalable and requires less sophisticated instrumentations.…”

Enhancing Intracellular Optical Performance and Stability of Engineered Nanomaterials via Aqueous Two-Phase Purification

“…Complete exchange of the surfactant encapsulation for a biocompatible molecule of choice, for example ssDNA, has been achieved and validated in multiple biological applications. − Finally, as evinced by this work, the purified-SWCNTs obtained from this process demonstrate superior optical stability and performance in cells. As the field of engineered nanomaterial purification continues to progress at a staggering rate by yielding samples with increased purity and chiral specificity, − biological sensors developed with purified-SWCNTs will continue to outperform and outpace those made with unpurified-SWCNTs. Many issues associated with unpurified-SWCNTs are directly resolved via our proposed method of initially dispersing a SWCNT in a surfactant, performing surfactant-based aqueous two-phase purification, and integrating a biocompatible functionalization of choice via surfactant exchange, thus optimizing the engineered nanomaterial’s performance for biomedical studies.…”