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Study on methodology for critical behavior near the sol-gel transition point

Research Project

Project/Area Number 02556015
Research Category

Grant-in-Aid for Developmental Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 製造化学・食品
Research InstitutionThe University of Tokyo

Principal Investigator

YANO Toshimasa  Univ.of Tokyo, Fac.of Agric., Prof., 農学部, 教授 (00011867)

Co-Investigator(Kenkyū-buntansha) ISHIZAKA Shozo  Univ.of Tsukuba, Inst.of Biol.Sci., Prof., 生物科学系, 教授 (10062499)
Project Period (FY) 1990 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥16,400,000 (Direct Cost: ¥16,400,000)
Fiscal Year 1991: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1990: ¥15,700,000 (Direct Cost: ¥15,700,000)
Keywordssol-gel transition / critical exponent / dynamic light scattering / percolation / correlation length / パ-コレ-ション / 動的ゲル化
Research Abstract

Not only Mechanical properties, which give macroscopic features of gels, but also light scattering, which gives features of gels on molecular level, were measured in order to analyze the critical phenomena near the sol-gel transition point.
dynamic light scattering method was carried out to determine the sol-gel transition point. From the fluctuations of scattered light intensity in the course of time, auto-correlation function was measured, and then by using Stokes-Einstein equation, cluster radius was calculated from the diffusion constant which was obtained from the correlation function. Results suggested that first, primary clusters were formed, and then the primary clusters polymerized with each other to form larger secondary clusters. The size of secondary clusters showed a tendency to diverge when the concentration approached the gelation point. By fitting the data with scaling law, the critical exponent was determined to be 0.84, which is not so far off from the critical exponen … More t of correlation length in percolation theory, which is said to be 0.9.
In the case of agarose, which forms clusters by non-covalent bonds, it was also possible to determine the cluster radius of agarose sol by using the dynamic light scattering method. Average cluster radius showed a tendency to diverge when the concentration increased and approached the sol-gel transition point. It was also possible to fit the data with scaling law, and the gelation concentration and the critical exponent were determined to be 4.5*10^<-3>(wt%) and 0.98 at the temperature of 27゚C.When the temperature was lowered and approsched the gelation temperature, the cluster radius became larger. By fitting the data, the gelation temperature and the critical exponent were determined to be 32.7゚C,and 1.36, for 0.15(wt%) agarose sol. The critical exponent thus obtained was larger than the theoretical value.
From the above results, it was suggested that by measuring the cluster radius distribution, concepts of percolation and scaling were shown to be effective when determining the physical property changes near the sol-gel transition point. Less

Report

(3 results)
  • 1991 Annual Research Report   Final Research Report Summary
  • 1990 Annual Research Report
  • Research Products

    (7 results)

All Other

All Publications (7 results)

  • [Publications] Toshimasa Yano: "Cluster size distribution and critical behavior of Polyacrylamide Sol near the sol-gel transition point" Polymer. (in preparation).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Toshimasa Yano: "Dynamic light scattering study on agarose near the sol-gel transition point" Biosci.Biotech.Biochem.(in preparation).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Toshimasa Yano: "Cluster size distribution and critical behavior of Polyacrylamide Sol near the sol-gel transition point" Polymer. (in preparation).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Toshimasa Yano: "Dynamic light scattering study on agarose near the sol-gel transition point" Biosci.Biotech.Biochem.(in preparation).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Toshimasa Yano: "Cluster size distribution and critical behavior of Polyacrylamide Sol near the sol-gel transition point" Polymer.

    • Related Report
      1991 Annual Research Report
  • [Publications] Toshimasa Yano: "Dynamic light scattering study on agarose near the sol-gel transition point" Biosci.Biotech.Biochem.

    • Related Report
      1991 Annual Research Report
  • [Publications] Toshimasa Yano: "Critical behavior and kinetic gelation of polyacrylamide solution" Agricultural Biological Chemistry.

    • Related Report
      1990 Annual Research Report

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Published: 1990-04-01   Modified: 2016-04-21  

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