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Prospective Energy Densities in the Forisome, a New Smart Material
Materials Science and Engineering: C (2006)
  • William F. Pickard
  • Michael Knoblauch
  • Winfried S. Peters
  • Amy Q. Shen
The forisome is a protein structure of plants which, in low Ca2+ solutions, assumes a crystalline condensed conformation and, at high Ca2+, swells to a dispersed conformation; this transition has been attributed to electrostatic deformation of protein “modules”. Forisomes could become an important smart material if the energy density of transformation approached 1 MJ m−3. Quantitation of the forisome as a charged porous continuum permeated by electrolyte fails by orders of magnitude to achieve this energy density electrostatically. However, condensed → dispersed transitions can be visualized alternatively: (i) an ionic bond near the surface of a forisome crystal dissolves to produce two bound surface charges; (ii) the anionic site bonds to Ca2+ becoming less negative; (iii) the two sites repel each other and move apart drawing in water; (iv) electrolyte anions are attracted, bringing with them bound water; (v) this transition propagates throughout the crystal, with incompressible imbibed electrolyte stabilizing the initial separation. With the above transition sequence, it seems possible to achieve an energy density of 0.5 MJ m−3 if the “modules” in the crystal are roughly 10 nm on a side.
  • Bond valence model,
  • Energy density Forisome,
  • Phloem,
  • P-protein,
  • Smart materials
Publication Date
January 1, 2006
Citation Information

William F. Pickard, Michael Knoblauch, Winfried S. Peters, and Amy Q. Shen. Prospective Energy Densities in the Forisome, a New Smart Material. Materials Science and Engineering: C (2006) 26: 104-112.

doi: 10.1016/j.msec.2005.06.055