| Abstract: |
Analysis of Particles and their Interactions
Lisa M. Fuhrer1, Helmut Cölfen 1
1University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Department of Chemistry
Lisa.Fuhrer@Uni-Konstanz.de
Applications for nanoparticles (NP) in science and industry have increased significantly in the last years due to their unique properties. One of these applications is the use of nanoparticles as building blocks for organized materials. The properties of these materials are determined from the elementary units and their interactions. Knowledge about the interaction parameters can help to understand and control the formation of these materials. One well established method for nanoparticle investigation is analytical ultracentrifugation (AUC). For the analysis, a nanoparticle dispersion is destabilised by increasing the ionic strength in the system with salts or by decreasing the solubility of the stabilizing ligand of the nanoparticles with another solvent. The formed agglomerates in the dispersion are then investgated with the AUC and also with dynamic light scattering (DLS) at different initial monomer concentrations. The obtained data points are fitted to an adaption of the Langmuir-Hill equation, which proved to be the best model for the investigated systems.The calculations can be applied on average values or be expanded to distributions. From the received interaction constants, Gibbs free energies, stoichiometries of the aggregation reaction and cooperativity can be calculated. Both parameters can be compared to thermodynamic parameters like enthalpy, entropy or Gibbs free energy obtained from independent isothermal titration calorimetry (ITC) measurements.
Acknowledgements
Financial support by the DFG is gratefully acknowledged. |
|---|
