1. Self-Assembly into the Condensed Phase
NIRT: Nanometer Stoichiometric Particle Compound Solutions and Control of their
Self-Assembly into the Condensed Phase
Chris Sorensen, C. Aakeröy, A. Chakrabarti, K. Klabunde and B. Law
Departments of Physics and Chemistry, Kansas State University
Goals
Synthesize a library of monodisperse functional nanoparticles (NP).
Study NP solution phase behavior and nucleation.
Controlled assembly of NP into 2d and 3d superlattices and gels.
Study NP solution surface and interfacial properties.
1. Synthesis
3. NP-NP Interactions
2. Solution Phase and Nucleation
Core-core
Core-ligand
Ligand-ligand
All mediated by the solvent
Solvated Metal Atom Dispersion Reactor
One phase; individual,
dissolved 5.5nm NPs.
Two phase; clusters
of NPs.
Au/C12SH NP (5.5nm) colloidal solution at different temperatures, solvent: t-butyltoluene + 2-butanone.
The phase transition is reversible!
Static and dynamic light scattering to observe cluster formation via nucleation as quench NP solution from one phase to two.
x = 1.3 is found in Au/C12SH NP superlattices.
4. Surface Interactions
Deep quench yields lots of small clusters, shallow quench a few big clusters.
Fat Fractals
Solution of Au/SHC11COOH in DMSO yields fractal/superlattice hybrid, with hydrogen bonds when quenched.
Droplets of Au/3-mercapto-1, 2-propanediol NP in H2O on glass. Left no NP, contact angle = 7o; right with NP, contact angle = 23o.
NPs of Au, Ag, CdSe, In. Dia. ~ 4 to 10nm
Ligands. Nonfunctionalized: CnSH, CnNH2, P(C8)3
Functionalized: HSCnCOOH, HSCnOH, HSCn polyols
bis(8-imidazol-1-yloctyl)disulfide
Solvents: toluene, t-butyltoluene, 2-butanone, CH3OH, water, DMSO.
NPs affect wetting.