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190 CHAPTER 2

2.22.5. Electrostriction in Other Systems

This section concentrates on the electrostrictional volume contraction of water
molecules in the hydration shell. However, electrostriction is a general phenomenon
and whenever there are electric fields on the order of the compression
of ions and molecules is likely to be significant (although less so than occurs by using
the compressibility figures usually given in books because these usually neglect the
decrease of with increase of pressure). Bockris and Gamboa have calculated the
degree of compression of and ions near interfaces. The spherical shape is
lost and the ions become lenslike in shape (Fig. 2.76).
Electrostriction in solids is important as the origin of piezoelectric effects. Von
Sterkenberg has measured the electrostrictive coefficients in alkaline (earth) fluorides
and found electrostriction there to be anisotropic.

Further Reading

Seminal
1. T. J. Webb, “Field and Pressure Near an Ion,” J. Am. Chem. Soc. 48: 2589 (1926).
2. H. S. Frank, “Theory of Electrostriction,” J. Chem. Phys. 23: 2033 (1955).
3. J. Padova, “Pressure Effects in Ionic Solutions,” J. Chem. Phys. 39: 1552 (1963).
4. J. E. Desnoyers, R. E. Verrall, and B. E. Conway, “Electrostriction in Electrolytes,” J.
Chem. Phys. 43: 243 (1965).

Papers
1. S. W. P. von Sterkenberg, J. Phys. Appl. Chem. 17: 69 (1982).
2. J. L. Ord, J. Electrochem. Soc. 138: 2934(1991).
3. J. O’M. Bockris, M. Gamboa-Aldeco, and M. Szklarczyk, J. Electroanal. Chem. 339: 355
(1992).
4. S. W. P. von Sterkenberg and Th. Kwaitaal, J. Appl. Phys. 25: 843 (1992).
5. M. Szklarzcyck, in Modern Aspects of Electrochemistry, Vol. 25, Ed. J. O’M. Bockris, B.
E. Conway, and R. H. White, Plenum, New York (1993).
6. G. Kloos, J. Appl. Phys. 28: 1680 (1995).
7. W. L. Marshall, J. Solution Chem. 22: 539 (1993).
8. T. M. Letcher, J. J. Paul, and R. L. Kay, J. Solution Chem. 20: 1001 (1991).

2.23. HYDRATION OF POLYIONS

2.23.1. Introduction

Most of the ion-exchange resins consist of polyions. A typical one is also the most
well known: Nafion, the structure of which is shown in Fig. 2.77; the figure also shows
the structure of some proteins (these are often polyelectrolytes).