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Carchesium stalk fibrillar matrix as a highly filled polymer network
Author(s) -
Hawkes Richard
Publication year - 1977
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040900106
Subject(s) - materials science , composite material , hysteresis , polymer , stiffness , modulus , ultimate tensile strength , viscoelasticity , young's modulus , softening , stress relaxation , elastic modulus , creep , physics , quantum mechanics
Glycerolated stalks of the sessile peritrich ciliate Carchesium sp. were treated with 10 −6 g ion/1 Ca 2+ to disrupt the contractile spasmoneme. The resulting preparation consisted primarily of the fibrillar matrix, a dense extracellular meshwork of microfibrils. Some mechanical properties of this preparation have been investigated. The matrix tensile force‐extension ratio relation for an initial stretch was characteristic of a soft, swollen polymer network, elastic modulus in young stalks 1.7 × 10 5 Nm −2 , in mature stalks 4.0 × 10 5 Nm −2 . The higher elastic modulus in mature stalks implies an increase in the interchain cross‐link frequency. In young stalks, elastic modulus was found to be independent of the ambient Ca 2+ concentration in the threshold range for spasmonemal contraction. Stalk relaxation was pronouncedly irreversible, showing stress softening and permanent hysteresis on repeated loading. Hysteresis was time independent and stiffness was not recovered after four hours at zero strain. Hysteresis was enhanced by repeated loading to the same tensile force. Stress‐strain hysteresis at a low extension ratio is characteristic of highly filled polymer networks in which polymer chains are interconnected via rigid filler particles as well as directly cross‐linked.