JSM-Seminar: Telechelic polymers as hierarchical self-assembling units from the molecular to the macroscopic scale
Prof. Christos N. Likos, Dr. Barbara Capone, Univ. Wien
- 28 Nov 2013 11:00
By means of multiscale molecular simulations, we analyze both telechelic star polymers (TSP’s) and telechelic brushes (TSB’s). We show that TSP’s are a simple, robust and tunable system, which hierarchically self-assembles into soft-patchy particles and mechanically stabilizes selected, open crystalline structures.
The self-aggregating patchy behavior can be fully controlled by the number of arms per star and by the fraction of attractive monomeric
units at the free ends of the arms.
Such self-assembled soft-patchy particles while forming, upon augmenting density, gel-like percolating networks, preserve properties as particle size, number and arrangement of patches per particle. In particular, we demonstrate that the ﬂexibility inherent in the softpatchy particles brings forward a novel mechanism that leads to the mechanical stability of diamond and simple cubic crystals over a wide range of densities, and for molecular sizes ranging from about 10 nm up to the micrometer scale.
TSB’s with a similar mechanism, show extremely interesting hierarchical selfassembling properties within the semi-dilute regime. Soft patches assemble on the surface; as the concentration is increased the patches order in various
quasi-bidimentional crystals. Similarly to the TSP’s, TSB’s aggregating behavior can be fully controlled by the grafting density and by the percentage of terminal attractive monomeric units. The self-assembled soft patches undergo a
disorder-order transition crystallising in quasi-2D crystals. The lattice in which the 2D crystals assemble can be controlled by the right choice of grafting density and percentage of attractive monomers.
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