Ellipsometry was employed to estimate the thickness of the interface 2 between two bulk layers of dissimilar polymers. The polymer/polymer combinations investigated were poly(methyl methacrylate) (PMMA)/ poly(styrene-co-acrylonitrile) (SAN) (AN content < 10 and > 33 wt%), PMMA/poly(methyl methacrylateco- styrene) (MS) and polystyrene/MS. They provide a series of immiscible combinations with various values of the Flory interaction parameter X ranging from 1.72 x 10-3 to 8.71 x 10-2. The bilayer specimen prepared by the spin-coating technique was annealed at 130°C (> T~) and the time variation of 2 was observed during annealing. The observed 2 attained a constant value after annealing for ~ 1 h and then remained constant. The constant value was assumed to be the equilibrium thickness. The thickness ranged from ~ 5 to 40 nm, depending on the magnitude of X. The thin interface (< ~ 10 nm) was nicely explained by the recent theory by Broseta et al., which deals with the effect of molecular weight on 2 within the strong segregation limit.
Посилання на статтю:
Ellipsometric studies on immiscible polymer-polymer interfaces / Satoshi Yukioka* and Takashi Inouet // Polymer. – 1993. – Vol 34. – P. 1256-1259.