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Updated: Dec 31, 2025
Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level
Published on: September 26, 2016
Direct observation of mobility of thin polymer layers via asymmetric interdiffusion using neutron reflectivity
Megumi Ooe1, Kairi Miyata1, Jun Yoshioka1
1Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577 Japan.
Abstract:
In this study, we investigated the diffusion dynamics at the interface between deuterated poly(methyl methacrylate) (d-PMMA) and protonated poly(methyl methacrylate) (h-PMMA) in two-layered thin films of d- and h-PMMA layers via neutron reflectivity (NR) measurements during isothermal annealing above the glass transition temperature Tg. When Tg of d-PMMA was higher than that of h-PMMA, the d-PMMA layer thickness increased with increasing annealing time ta and, simultaneously, the h-PMMA layer thickness decreased. However, the opposite ta dependence of the layer thicknesses was observed, if the Tg of d-PMMA was decreased by the increase in the fraction of the low-molecular weight d-PMMA: With increasing ta, the d-PMMA layer thickness decreased and the h-PMMA layer thickness increased when Tg of d-PMMA was lower than that of h-PMMA. This change in the ta dependence of the layer thickness was related to the change in the mobility of the d-PMMA layer accompanied by the change in the Tg value of d-PMMA. With the decrease in the d-PMMA layer thickness from 49 nm to 13 nm, when the h-PMMA layer thickness was maintained, the ta dependence of the layer thickness changed and the mobility of the d-PMMA layer dramatically increased. These results suggest that the mobility of thin polymer films can be determined by the observation of interfacial dynamics via NR measurements.
