[nanoPost] Molecular modeling in design of dye-clay hybrid nanostructures

Research Centre Czech Rep

The use of molecular modeling (molecular mechanics and molecular dynamics) will be illustrated on the design of dyeclay
hybrid nanostructures prepared for optical applications.

In the design of nanostructures with photofunctions the
structural ordering is the key factor affecting the optical properties. Present work is focused on nanomaterials based on
layer silicates intercalated with organic dyes. The main problem in the molecular nanotechnology based on the hostguest
interaction is the complementarity of the guest molecules with the host structure. This complementarity is
described by a series of factors like: charge distribution on the host matrix and guest molecules, the presence and
arrangement of active sites on the host structure, the size and shape of guests [3]. Molecular modeling using empirical
force field represents just the right tool allowing a preliminary estimation of the host-guest complementarity and
prediction of structure and properties for nanomaterial desing in molecular nanotechnology.
We used molecular modeling in Materials Studio modeling environment combined with X-ray powder diffraction and IR
spectroscopy to analyze the structure and to elucidate the structure-properties relationship in nanomaterials based on
layer silicates intercalated with organic dyes. Our investigation was focused on fluorescence and on the possible
fluorescence tuning by combining various organic dyes with different phyllosilicate matrices. Strategy of modeling
including the search for global energy minimum and the test of the force field was worked out, based on all available
experimental data (first of all X-ray powder diffraction and IR spectroscopy) [4,5].
Molecular modeling revealed the structure ordering of guest molecules in the interlayer space of clays for a series of dye
molecules, helped to find the suitable guest matrix (type of layer silicate), to choose the suitable host-guest combination,
the optimum guest concentration, the intercalation conditions, to understand the structure-properties relationship and
consequently to correct the technology for the following systems: Rhodamine B, Methylene blue, methyl red-clays
intercalated into the structure of various types of phyllosilicates.