| Project/Area Number |
63540272
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
物性一般（含極低温･固体物性に対する理論）
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
HIROTSU Shunsuke TOKYO INST.TECH. DEPT.SCI. PROFESSOR, 理学部, 教授 (40016069)
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| Co-Investigator(Kenkyū-buntansha) |
山本 郁夫 横浜国立大学, 教育学部, 助手 (70126332)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1989: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1988: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | POLYMER GEL / VOLUME PHASE TRANSITION / GEL-GEL TRANSITION / SPINODAL DECOMPOSITION / LIGHT SCATTERING / ELASTIC CONSTANT / BRILLOUIN SCATTERING / PATTERN FORMATION / 弾性不安定性 / ゲルの体積相転移 / ゲル-ゲル転移 / スピノーダル分解 |
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| Research Abstract |
1. Dynamical mechanism of spinodal decomposition (SD) in NIPA gel. By combining multi-channel photodetectors and a personal computer, we made a time- and position-sensitive light-scattering photometer. With this apparatus, evolution of the unstable fluctuation in NIPA gel brought into an unstable region was investigated. It was found that at least two kinds of SD coexists in this gel, which were tentatively assigned as the surface SD and the bulk SD. On the basis of the Flory-type phenomenological theory, it was pointed out that three types of SD, i.e. those between swollen phase-shrunken phase, swollen phase-pure solvent, and shrunken phase-pure solvent, exist in NIPA gel. To make correspondence between the theoretical prediction and the experimental results, further detailed studies will have to be made.
2. High-frequency elastic measurements by Brillouin scattering. Velocity and attenuation of hyper sound near the volume phase transition in NIPA gel were measured by means of Brillouin scattering. Large step-like anomalies in both quantities were found at the transition point.
3. Evolution of patterns on the surface of gels during swelling. It was found on AA and NIPA gels that the evolution of honey-comb like pattern on gel surface follows a power law, the index of which is nearly 1.0.
4. Development of a new method to impose a homogeneous uniaxial tension on gels and some measurements utilizing this technique. (1) Dependence of the volume phase transition on external stresses. (2) Measurements of softening of the bulk modulus and the negative Poisson's ratio. It is remarkable that this measurement is the first report to confirm the existence in nature of a material with negative Poisson's ratio. (3) Light-scattering measurement of the dependence of concentration fluctuation of gel network upon external stresses.
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