Collapse of polymer brushes grafted onto planar ... - Wageningen UR

SPINODAL DECOMPOSITION IN BINARY POLYMERIC BLENDS
M.E. Velázquez-Sánchez, P.D. Anderson, P.G.T. van der Varst, G. de With
Technische Universiteit Eindhoven,
Postbus 513, 5600 MB Eindhoven, The Netherlands
email: M.velazquez-sanchez@tue.nl
ABSTRACT
This work aims to predict the morphology development in films, on a substrate, made from binary polymeric
blends that undergo phase separation via a spinodal decomposition mechanism. From thermodynamics it is
possible to predict the spinodal and binodal regions of a system, once the Flory-Huggins interaction
parameter is known; however to know how the morphology develops as a function of time, the diffusion
equation must be solved. A diffuse-interface model that couples the thermodynamics and the hydrodynamics
of a binary system is used. As an input, this model uses a chemical potential where the wall interaction and
the non-local effects in the enthalpy and the entropy are taken into account. Preliminary results show that the
introduction of the wall potential plays an important role in the development of the spinodal decomposition,
resulting in a more complex morphology, where formation of macroscopic layers close to the substrate is
obtained. Additionally, the growth rate of concentration fluctuations is significantly influenced by the wall.