Change of Free Volume in Polymer Gels As Studied by Positron Annihilation Lifetimes

• Authors: K. Ito , Y. Ujihira , T. Yamashita , K. Horie
• Languages of publication: EN

Abstracts

EN

Variations of a free volume size of a poly(N-isopropylacrylamide) gel and a polyacrylamide gel during a volume phase transition induced by a change of external environment - temperature, solvent composition, pH, and ion strength, are described. The free volume size is probed by positron annihilation lifetime technique. Variations of the free volume size suggest that a nanoscopic environment of the gels is affected by the free volume of the solvent phase and an interaction between the polymer chain and the solvent molecule in the swollen state, and by the aggregation of the polymer chain and a balance of the interaction among the polymer chain and the solvent molecules in the collapsed state. It is revealed that the free volume size reflects the essential change of the nanoscopic environment in the gels which could induce the macroscopic volume phase transition.

Keywords

EN

82.70.Gg

Discipline

• 82.70.Gg: Gels and sols

• Journal: Acta Physica Polonica A
• Year: 1999
• Volume: 95
• Issue: 4
• Pages: 551-556

Dates

published

1999-04

Contributors

author

K. Ito

• Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan

author

Y. Ujihira

• Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan

author

T. Yamashita

• Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

author

K. Horie

• Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Identifiers

DOI

10.12693/APhysPolA.95.551