Phase Separation and Dewetting of Polymer Blend Thin Films
Phase separation and dewetting of polystyrene (PS) and Poly(vinyl methyl
ether ) (PVME) blend thin films were studied as a function of film thickness
by means of light scattering, AFM, optical microscope, and neutron reflectivity.
Characteristic wavelength as a function of film thickness
In a range of thickness above 1ƒÊm, phase separation occurs preferentially,
and below 100 nm dewetting occurs preferentially. In between (100
nm - 1ƒÊm) phase separation and dewetting coexist and no characteristic
length is observed in LS profiles.
NR measurements revealed that concentration fluctuations occur at interface before dewetting.This may trigger the dewetting.The above figure shows a schematic sketch of phase separation-assisted dewtting.