Chemical Grafting, Exfoliation and Dynamics of One and Two-Dimensional Boron-Nitride Nanostructures

William Marsh Rice University, Houston TX

Investigators

Abstract

Advances in nanotechnology have been central to the creation of novel biomedical applications, energy transport and storage systems, aerospace materials, and solar energy conversion. This research explores novel nanostructures made of boron nitride (BN). Graphene is one type of nanocarbon in which a honeycomb arrangement of carbon atoms forms a thin sheet. When graphene is seamlessly rolled, it forms carbon nanotubes, a well-known material. Alternating boron and nitrogen atoms can replace carbon in carbon nanotubes to form BN nanostructures, BN nanostructures are wide band gap semiconductors with outstanding thermal stability, in contrast to their carbon analogs. Concentrating on these special differences, Professors Angel Marti and Matteo Pasquali of Rice University, are exploring how to tune the properties of BN nanostructures by attaching chemical groups to their surfaces and by monitoring their movements in solution. This information may enable the assembly of these nanostructures into sophisticated systems with tailored physical, chemical, and mechanical properties. This research may accelerate discovery and innovation in producing insulating films, corrosion protections, and UV optoelectronics. Professors Marti and Pasquali disseminate their research to the greater community through press releases and YouTube videos. They provide cutting-edge nanoscience activities such as workshops, talks, and summer research opportunities by reaching out to high school, college, and graduate students, paying particular attention to underrepresented groups. The research team recruits and mentors undergraduate students from Puerto Rico via the Louis Stokes Alliances for Minority Participation (LSAMP) Program. LSAMP facilitates the training of underrepresented students in cutting-edge nanoscience research. Supported by the Macromolecular, Supramolecular and Nanochemistry Program of NSF's Chemistry Division, Professors Marti and Pasquali are addressing fundamental challenges of BN nanostructures such as surface functionalization, exfoliation, dispersion, and imaging. BN nanostructures are functionalized with a variety of groups by virtue of organic radicals produced under Billups-Birch conditions (lithium in liquid ammonia). The properties of these functionalized structures are studied in different environments and solvents. Furthermore, the dispersibility of BN materials are studied in surfactants having different charges and polarities to understand the conditions that lead to their dispersion in aqueous solution. Dispersed structures are studied by fluorescence microscopy, using special fluorescent surfactants, to understand the dynamics of the BN nanotubes in solution. Overcoming these challenges advances fundamental knowledge of the chemistry and properties of one- and two-dimensional BN nanostructures. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.