Ab. Burdin et Aa. Tager, PHASE-TRANSITIONS IN THIN-FILMS OF BLENDS OF POLY(METHYLMETHACRYLATE)AND CRYSTALLIZABLE POLY(ETHYLENE OXIDE), Vysokomolekularnye soedinenia. Seria A, 37(5), 1995, pp. 850-854
Phase separation in thin films of blends of amorphous PMMA and crystal
line PEO was studied. Films of various thicknesses were prepared by ca
sting 3% solutions in chloroform onto a silicate glass plate and a hyd
rophobic glass substrate. Phase diagrams were constructed by means of
differential thermal analysis (by determining T-m of PEO in the blends
) and light transmission. Phase separation occurs differently in diffe
rent composition ranges of the system, depending on the molecular mass
es of the constituent polymers: either the second amorphous (the bound
ary curves are binodals with the upper critical point) or a crystallin
e phase (with liquidus curves) is formed. The crystallization temperat
ure of PEO in the blend, as determined by small-angle anisotropic ligh
t scattering, is dependent on the film thickness, the molecular masses
of the components, the composition of the blend, and the nature of th
e substrate. The results were discussed in terms of present-day views
on the structure of surface adsorption layers in polymers.