Thickness dependence of the dynamics in thin films of isotactic poly (methylmethacrylate)

Abstract.The film thickness dependence of both the glass transition temperature (Tg) and the 1 kHz alpha relaxation were studied for thin films of isotactic Poly (methylmethacrylate) (i-PMMA) supported on aluminium substrates. Films in the thickness range 7-200 nm were studied. The ellipsometrically determined Tg was found to show reductions for films thinner than 60 nm, with the largest observed reduction being 12 K for a 7 nm thick film. …