Thermodynamic stability and structural properties of cluster crystals formed by amphiphilic dendrimers
- Author(s)
- Dominic A. Lenz, Bianca Mladek, Christos N. Likos, Ronald Blaak
- Abstract
We pursue the goal of finding real-world examples of macromolecular aggregates that form cluster crystals, which have been predicted on the basis of coarse-grained, ultrasoft pair potentials belonging to a particular mathematical class [B. M. Mladek et al., Phys. Rev. Lett. 46, 045701 (2006)]. For this purpose, we examine in detail the phase behavior and structural properties of model amphiphilic dendrimers of the second generation by means of monomer-resolved computer simulations. On augmenting the density of these systems, a fluid comprised of clusters that contain several overlapping and penetrating macromolecules is spontaneously formed. Upon further compression of the system, a transition to multi-occupancy crystals takes place, the thermodynamic stability of which is demonstrated by means of free-energy calculations, and where the FCC is preferred over the BCC-phase. Contrary to predictions for coarse-grained theoretical models in which the particles interact exclusively by effective pair potentials, the internal degrees of freedom of these molecules cause the lattice constant to be density-dependent. Furthermore, the mechanical stability of monodisperse BCC and FCC cluster crystals is restricted to a bounded region in the plane of cluster occupation number versus density. The structural properties of the dendrimers in the dense crystals, including their overall sizes and the distribution of monomers are also thoroughly analyzed.
- Organisation(s)
- Computational and Soft Matter Physics, Department of Structural and Computational Biology
- External organisation(s)
- Max F. Perutz Laboratories GmbH (MFPL)
- Journal
- Journal of Chemical Physics
- Volume
- 144
- No. of pages
- 15
- ISSN
- 0021-9606
- DOI
- https://doi.org/10.1063/1.4950953
- Publication date
- 05-2016
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103015 Condensed matter
- Keywords
- ASJC Scopus subject areas
- General Physics and Astronomy, Physical and Theoretical Chemistry
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/20f1179c-9ed0-45a2-b075-cd9aada62568