Polymer Blends

Thermodynamically miscible polymer blends show two glass temperatures that reflect the freezing of the component's segmental dynamics. A closely related issue is that of dynamic heterogeneity in miscible polymer blends. Dynamic heterogeneity requires a large disparity in the glass temperatures of the parent homopolymers. However such polymer mixtures are usually composed from monomers of different polarity and/or rigidity that tend to phase separate. Recently we have followed a different strategy by exploring mixtures of a homopolymer with its oligomers through a combined approach that involves multi-scale simulation methods with experiments (dielectric spectroscopy). This system exhibits the larger possible dynamic asymmetry, and at the same time, possesses the highest possible miscibility. By employing the different methods we cover about 12 orders of magnitude in time, and we are able to show [3] that a single intra-molecular length scale does not suffice to describe the slower segmental dynamics contrary to current theories.

Collaborators: V.A. Harmandaris (Univ. of Crete), K. Kremer (MPI-P), K. Koynov (MPI-P)

Recent representative publications (2011-2016)

[1] M. Doroshenko, M. Gonzales, A. Best, H.-J. Butt, K. Koynov, G. Floudas

“Monitoring the dynamics of phase separation in a polymer blend by confocal imaging and fluorescence correlation spectroscopy”, 

Macromol. Rapid Commun. 13, 1568, 2012.

[2] G. Zardalidis, G. Floudas

“Pressure effects on the Dynamic Heterogeneity of Miscible Poly(vinyl acetate)/Poly(ethylene oxide) Blends”, 

Macromolecules 45, 6272, 2012.

[3] V.A. Harmandaris, K. Kremer, and G. Floudas

“Dynamic Heterogeneity in Fully Miscible Blends of Polystyrene with Oligostyrene”, 

Phys. Rev. Lett. 110, 165701, 2013.

[4] T.P. Corrales, D. Laroze, G. Zardalidis, G. Floudas, H.-J. Butt, M.Kappl,

“Dynamic Heterogeneity and Phase Separation Kinetics in Miscible Poly(vinyl acetate)/Poly(ethylene oxide) Blends by Local Dielectric Spectroscopy”, 

Macromolecules 46, 7458, 2013.