An Investigation of Boron Nitride Nanomaterial Functionalization

At the Army Research Laboratory

by Kevin Waters
Follow along @ kwaters4.github.io/Presentation/ARL/

My Background


Hypothesis

"We can accurately predict the interface between biological molecules and nanomaterials in physiological conditions."

Nanomaterials

Materials with at least one dimension in the sub-micron range.

  • Ratio of surface to bulk atoms changes
  • Bulk properties are not present at this scale
  • Adding one atom changes the properties of the material
  • Large configuration spaces to search
  • Prediction can be utilized, but caution should be practiced

Examples of Nanomaterials

  • Clusters
  • Nanoparticles
  • Fullerenes
  • Nanotubes
  • 2D-Materials
  • A. K. Geim et. al Nature Materials (2007) 6: 183

    • Boron Nitride Nanotubes

    • Predicted in 1994
    • Synthesized in 1995
    • Typically considred a wide band gap semiconductor
    • Parameters to consider
      • Chirality (n,n), (n,0), (n,m)
      • Diameter
      • Layers
    • Excellent chemical and thermal stability

    Boron Nitride Nanotubes

  • Steel, "A Primer on Carbon Nanotubes – Part 1"

    • Difference between Carbon and Boron Nitride Nanomaterials

    • Semi-ionic bonds (B-N) versus covalent (C-C)
    • Interlayer interactions are stronger
    • BNNTs are mostly zig-zag, CNTs statistcally equivalent.
    • All BNNTs are semi-conducting, CNTs vary based on chirality
    • Cytotoxicity still being investigated for BNNTs

    Boron Nitride Nanotubes (Band Gap)

    Rimola et. al. (2013) PCCP 15:13190

    Biological Molecules

    • Carbohydrates
    • DNA (Nucleotides)
    • Lipids
    • Proteins (Amino Acids, Peptides)
    • etc.

    Methods and Tools

    • Solving the system's electronic wavefunction
      • Schrödinger Equation
      • Density Functional Theory (DFT)
      • Ab Initio Molecular Dynamics (AIMD)
      • High Performance Computing Platform

    Amino Acids Conjugated with Boron Nitride Nanomaterials

    Waters et. al. (2017) ACS Omega 2:76

    Proteins
    pdb : 3V03
    Waters et. al. (2017) ACS Omega 2:76

    Conjugated Structures

    Binding Energies

    Mechanical Properties of 2D BN2

    Waters et. al. (2018) Journal of Physics: Condensed Matter 30: 13

    Experimental Functionalization


    Sainsbury et. al. (2007) JACS 111:12992

    BN Electronic Structure Evolution

    Coverage (%) Band Gap (eV) Binding Energy (eV)
    0 4.25
    16 3.34 -0.74
    25 3.11 -0.70
    50 2.25 0.72

    BN2 Monolayer

    • Supercell : 2B + 4N
    • Symmetry : Amm2 (38)
    • Lattice Vectors
      • a : 6.84 Å
      • b : 2.55 Å
    • Bonds
      • N-N : 1.29 Å
      • N-B : 1.34 Å
      • B-N : 1.50 Å
    • Stability : Phonon Spectra

    BN2 Band Structure (Orbital Projected)

    Hooke's Law / Elastic Tensor


    • σI is the stress tensor
    • CIJ is the elastic tensor
    • ηJ is the stain tensor

    Orthorhombic Symmetry in 2D

    Results


    N/m Graphene1 This Work BN2 This Work
    C11 358.1 353.7 293.2 290.5
    C12 60.4 61.7 66.1 64.4
    C22
    C66 148.9 144.9 113.5 113.1

    Results


    N/m Graphene1 BN2 BN2
    C11 358.1 293.2 368.8
    C12 60.4 66.1 47.2
    C22 153.3
    C66 148.9 113.5 58.7

    Mechanical Properties of Crystalline Poly Ether Ether Ketone (PEEK)

    Pisani et. al. (2018) In Prepartation
    • The Institute for Ultra-Strong Composites by Computational Design
    • NASA Space Technology Research Institute
    • Computationally-driven development of CNT-based ultra high strength lightweight structural materials
    • Project lead by Dr. Odegard at Michigan Tech.

    PEEK

    • Investigating properties of the polymers for future applications
    • ReaxxFF testing and validation
    • Comparing crystalline data (MD vs. DFT)
    • Challenging to model amorphous PEEK with electron approach

    Elastic Constants

    (GPa) MD DFT
    C11 140.5 ± 7.31 133.3
    C22 4.87 ± 1.56 15.5
    C33 7.18 ± 1.34 15.3
    C44 0.24 ± 0.16 14.0
    C55 3.79 ± 3.00 9.0
    C66 3.37 ± 0.36 4.8

    Poisson's Ratio

    MD DFT
    ν12 0.88 ± 0.24 0.38
    ν13 -0.01 ± 0.58 -0.33
    ν23 0.50 ± 0.12 0.38

    Gold Deposition on Boron Nitride Nanomaterials

    Waters et. al. (2018) In Prepartation

    Gold Quantum Dots on Boron Nitride

    Boron Nitride Nanotubes Functionalized with Gold Quantum Dots

    Gold Flakes on Boron Nitride

    Gold Flakes on Boron Nitride

    Unpublished work from Bhandari et. al.

    Gold Cluster Structures

    2D 3D
  • Unpublished work from Waters et. al.
  • L. Xiao et al. (2004) Chemical Physics Letters 392, 452
  • L. Xiao et al. (2006) The Journal of Chemical Physics 114309
  • G. Chen et. al. (2010) The Journal of Chemical Physics 194306
    •

    Gold Cluster Cohesive Energy

    Gold Clusters on BN

    • Substrate of h-BN
    • vDW Interactions
    • Deformation for 3D clusters

    Gold/BN Binding Energies

    Gold Cluster Electronic Gap

    Conjugated Gold Cluster Electronic Gap

    Current/Future Work

    • Improve accuracy for the exact exchange integral in PBC (NWChem)
    • AIMD studies on the peptide/BNNTs interface in a solvated environment
    • Test plane-wave AIMD simulations with O(N) DFT methods

    Challenges

    • Computation power (Hardware/Software)
    • Scaling of theories (CCSD vs. DFT vs. MD)
    • Inclusion of all releveant parameters (ions, solution, pH, etc.)
    • Asking the right questions

    Conclusion

    • Laid the foundation for protein BNNT simulations
    • Started to investigate functionalized structures
    • Building framework for future large scale applications
    • Flexibility to look at similar structures (e.g. Polymers)

    Acknowledgements

    • Ravindra Pandey
    • Eric Bylasksa
    • Gregory Odegard
    • Nabanita Saikia
    • Max Seel
    • Wil Slough
    • Yoke Khin Yap

    Questions