Counterion dynamics of κ- and ι-carrageenan aqueous solutions investigated by the dielectric properties

Makoto Takemasa, Akio Chiba, Munehiro Date

    Research output: Contribution to journalArticle

    19 Citations (Scopus)

    Abstract

    The temperature dependence of the dielectric properties of κ- and ι-carrageenan aqueous solutions with various counterion species, K, Ca, and Na, were investigated over the frequency range 10-2-106 Hz and the temperature range 2.0-80.0 °C. In the case of κ-carrageenan solutions, just below the coil-to-helix transition temperature, TCH, the dc conductivity sharply decreases within a few degrees of temperature. In contrast, the sharp decrease was not observed for ι-carrageenan solutions. The dielectric relaxation process with the relaxation time ∼100 μs, which can be assigned to the counterion fluctuation in the parallel direction to the helical axis, arises below TCH. Just below TCH, the relaxation strength increases sharply with decreasing temperature for both the carrageenan type with all the counterion species exhibiting the coil-to-helix transition, reaching ∼103 at the temperatures far below TCH. These findings indicate that the counterions are tightly bound to helical molecules due to an increase of the charge density along the helical axis during the coil-helix transition. The relaxation time reflecting the fluctuation distance increases sharply in the initial stage of gelation and gradually reaches a constant value. We think that the formation of the high charge density region, which is connected with the aggregated region of helices, is determined by which process, a growth of the length of the helices or the aggregation of the helices, precedes in the initial stage of gelation.

    Original languageEnglish
    Pages (from-to)5595-5600
    Number of pages6
    JournalMacromolecules
    Volume35
    Issue number14
    DOIs
    Publication statusPublished - 2002 Jul 2

    Fingerprint

    Carrageenan
    Dielectric properties
    Gelation
    Charge density
    Relaxation time
    Temperature
    Dielectric relaxation
    Relaxation processes
    Superconducting transition temperature
    Agglomeration
    Molecules

    ASJC Scopus subject areas

    • Materials Chemistry

    Cite this

    Counterion dynamics of κ- and ι-carrageenan aqueous solutions investigated by the dielectric properties. / Takemasa, Makoto; Chiba, Akio; Date, Munehiro.

    In: Macromolecules, Vol. 35, No. 14, 02.07.2002, p. 5595-5600.

    Research output: Contribution to journalArticle

    Takemasa, Makoto ; Chiba, Akio ; Date, Munehiro. / Counterion dynamics of κ- and ι-carrageenan aqueous solutions investigated by the dielectric properties. In: Macromolecules. 2002 ; Vol. 35, No. 14. pp. 5595-5600.
    @article{e81627922d8440a69bc846417c436851,
    title = "Counterion dynamics of κ- and ι-carrageenan aqueous solutions investigated by the dielectric properties",
    abstract = "The temperature dependence of the dielectric properties of κ- and ι-carrageenan aqueous solutions with various counterion species, K, Ca, and Na, were investigated over the frequency range 10-2-106 Hz and the temperature range 2.0-80.0 °C. In the case of κ-carrageenan solutions, just below the coil-to-helix transition temperature, TCH, the dc conductivity sharply decreases within a few degrees of temperature. In contrast, the sharp decrease was not observed for ι-carrageenan solutions. The dielectric relaxation process with the relaxation time ∼100 μs, which can be assigned to the counterion fluctuation in the parallel direction to the helical axis, arises below TCH. Just below TCH, the relaxation strength increases sharply with decreasing temperature for both the carrageenan type with all the counterion species exhibiting the coil-to-helix transition, reaching ∼103 at the temperatures far below TCH. These findings indicate that the counterions are tightly bound to helical molecules due to an increase of the charge density along the helical axis during the coil-helix transition. The relaxation time reflecting the fluctuation distance increases sharply in the initial stage of gelation and gradually reaches a constant value. We think that the formation of the high charge density region, which is connected with the aggregated region of helices, is determined by which process, a growth of the length of the helices or the aggregation of the helices, precedes in the initial stage of gelation.",
    author = "Makoto Takemasa and Akio Chiba and Munehiro Date",
    year = "2002",
    month = "7",
    day = "2",
    doi = "10.1021/ma020206f",
    language = "English",
    volume = "35",
    pages = "5595--5600",
    journal = "Macromolecules",
    issn = "0024-9297",
    publisher = "American Chemical Society",
    number = "14",

    }

    TY - JOUR

    T1 - Counterion dynamics of κ- and ι-carrageenan aqueous solutions investigated by the dielectric properties

    AU - Takemasa, Makoto

    AU - Chiba, Akio

    AU - Date, Munehiro

    PY - 2002/7/2

    Y1 - 2002/7/2

    N2 - The temperature dependence of the dielectric properties of κ- and ι-carrageenan aqueous solutions with various counterion species, K, Ca, and Na, were investigated over the frequency range 10-2-106 Hz and the temperature range 2.0-80.0 °C. In the case of κ-carrageenan solutions, just below the coil-to-helix transition temperature, TCH, the dc conductivity sharply decreases within a few degrees of temperature. In contrast, the sharp decrease was not observed for ι-carrageenan solutions. The dielectric relaxation process with the relaxation time ∼100 μs, which can be assigned to the counterion fluctuation in the parallel direction to the helical axis, arises below TCH. Just below TCH, the relaxation strength increases sharply with decreasing temperature for both the carrageenan type with all the counterion species exhibiting the coil-to-helix transition, reaching ∼103 at the temperatures far below TCH. These findings indicate that the counterions are tightly bound to helical molecules due to an increase of the charge density along the helical axis during the coil-helix transition. The relaxation time reflecting the fluctuation distance increases sharply in the initial stage of gelation and gradually reaches a constant value. We think that the formation of the high charge density region, which is connected with the aggregated region of helices, is determined by which process, a growth of the length of the helices or the aggregation of the helices, precedes in the initial stage of gelation.

    AB - The temperature dependence of the dielectric properties of κ- and ι-carrageenan aqueous solutions with various counterion species, K, Ca, and Na, were investigated over the frequency range 10-2-106 Hz and the temperature range 2.0-80.0 °C. In the case of κ-carrageenan solutions, just below the coil-to-helix transition temperature, TCH, the dc conductivity sharply decreases within a few degrees of temperature. In contrast, the sharp decrease was not observed for ι-carrageenan solutions. The dielectric relaxation process with the relaxation time ∼100 μs, which can be assigned to the counterion fluctuation in the parallel direction to the helical axis, arises below TCH. Just below TCH, the relaxation strength increases sharply with decreasing temperature for both the carrageenan type with all the counterion species exhibiting the coil-to-helix transition, reaching ∼103 at the temperatures far below TCH. These findings indicate that the counterions are tightly bound to helical molecules due to an increase of the charge density along the helical axis during the coil-helix transition. The relaxation time reflecting the fluctuation distance increases sharply in the initial stage of gelation and gradually reaches a constant value. We think that the formation of the high charge density region, which is connected with the aggregated region of helices, is determined by which process, a growth of the length of the helices or the aggregation of the helices, precedes in the initial stage of gelation.

    UR - http://www.scopus.com/inward/record.url?scp=0037008109&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=0037008109&partnerID=8YFLogxK

    U2 - 10.1021/ma020206f

    DO - 10.1021/ma020206f

    M3 - Article

    AN - SCOPUS:0037008109

    VL - 35

    SP - 5595

    EP - 5600

    JO - Macromolecules

    JF - Macromolecules

    SN - 0024-9297

    IS - 14

    ER -