Poly(4-vinylpyridine) adsorption on boron nitride nanotubes and hexagonal boron nitride: A comparative molecular dynamics study

One of the foremost challenges in the boron nitride nanotube (BNNT) community is selective separation of BNNTs from the as-produced mixture of various hexagonal BN (hBN) phases. Recently, a polymer with a pyridine group, poly(4-vinylpyridine) (P4VP) has proven to be effective for BNNT dispersion. Here, we performed all-atom molecular dynamics simulations to elucidate the selective dispersion mechanism by characterizing interfacial interactions of P4VP with 12 different types of BNNTs, as well as with 8 different sizes of hBN sheets. The results revealed a prominent effect of lattice curvature (i.e., tube diameter) and morphology (i.e., tubular or planar) on the polymer adsorption conformation and their binding energetics. Remarkably, P4VP tightly wrapped around BNNTs with a well-defined helical pitch, while it formed an extended random coil on planar hBNs. A comparative study on carbon nanotubes and graphenes also highlighted the critical role of electrostatic interaction of P4VP with partially charged BN lattice.

Automated summary

This study employs molecular dynamics simulations to investigate the interfacial interactions between poly(4-vinylpyridine) and various types of boron nitride nanotubes as well as hexagonal boron nitride sheets. The results demonstrate the significant influence of lattice curvature and morphology on the polymer adsorption conformation and binding energetics.