Interaction of DNA-Complexed Boron Nitride Nanotubes and Cosolvents Impacts Dispersion and Length Characteristics

Abstract

Processing boron nitride nanotubes (BNNTs) for applications ranging from nanomedicine to electronics generally requires dispersions of nanotubes that are stable in various compounds and solvents. We show that alcohol/water cosolvents, particularly isopropyl alcohol (IPA), are essential for the complexation of BNNTs with DNA under mild bath sonication. The resulting DNA-wrapped BNNT complexes are highly stable during purification and solvent exchange from cosolvents to water, providing potential for the versatile liquid-phase processing of BNNTs. Via molecular dynamics simulations, we demonstrate that IPA assists in the solvation of BNNTs due to its pseudosurfactant nature by verifying that water is replaced in the solvation layer as IPA is added. We quantify the solvation free energy of BNNTs in various IPA/water mixtures and observe a nonmonotonic trend, highlighting the importance of utilizing solvent−nanotube interactions in nanomaterial dispersions. Additionally, we show that nanotube lengths can be characterized by rheology measurements via determining the viscosity of dilute dispersions of DNA−BNNTs. This represents the bulk sample property in the liquid state, as compared to conventional imaging techniques that require surface deposition and drying. Our results also demonstrate that BNNT dispersions exhibit the rheological behavior of dilute Brownian rigid rods, which can be further exploited for the controlled processing and property enhancement of BNNT-enabled assemblies such as films and fibers.

Boron nitride nanotubes enhance mechanical properties of fibers from nanotube/polyvinyl alcohol dispersions

“… 25,51 We estimate the number average length of SDC–BNNTs to be roughly 324 ± 133 nm based on our prior work utilizing the same sample dispersion method. 52 To begin with, we tested how the purity of BNNT synthetic material, and the nanotube concentration affect the mechanical properties of fibers coagulated in EtOH, while keeping the PVA content in BNNTs/PVA dispersions at 5 mass% ( Fig. 2 , Tables S2 and S3 † ).…”

Hexagonal boron nitride exfoliation and dispersion

“…136 In 2021, Kode reported a non-covalent complexation of hBN and DNA to make dispersions in phosphate buffered saline solutions, with concentrations up to 8% in mass. 137 Quian and coworkers studied the use of flavin mononucleotide (FMN) for liquid phase exfoliation of hBN. 138 They determined that FMN self-assembles on hBN via π-π interactions and intermolecular hydrogen bonds, which was initially predicted by molecular dynamic simulations.…”

Lyotropic Boron Nitride Nanotube Liquid Crystals: Preparation, Characterization, and Wet-Spinning for Fabrication of Composite Fiber

“…Moreover, the unique properties of BNNTs, such as their high chemical resistivity and oxidation tolerance, , electrical insulation, , neutron absorption, and piezoelectricity, have greenlighted their use as a complementary nanomaterial to CNTs. Therefore, a growing interest in BNNT applications has recently been pushing the development of fabrication methods for composites that contain high concentrations (or high density) of this material to maximize the functionality of BNNTs listed above. , However, due to the highly inert and hydrophobic surface properties of BNNTs, stable BNNT dispersions are rarely prepared at high concentrations in solvents and polymeric resins, even though various efforts using covalent/non-covalent functionalization methods − with polymer or biopolymer wrapping, − surfactants, − and strong acids − have been proposed. Difficulties in preparing stable BNNT dispersions at high concentrations have significantly limited the development of composite fabrication techniques with high solid contents of BNNTs so far.…”