Anamolous Hyperpolarization observed in polyacrylate gels and their implications on polyelectrolyte theory*

<script id="th-iframe-script" src="chrome-extension://ofdopmlmgifpfkijadehmhjccbefaeec/assets/comms/commsiframe.js"></script>Poly(acrylate) gels have been shown to exhibit electrical potentials in the range normally afforded by living cells. We have unexpectedly found that bathing poly(acrylate) gels in aqueous solutions of monovalent salts such as KH₂PO₄ in a narrow concentration range (ca. 8-16 mM) leads to a softening of gels without measurable volume changes. Moreover, electrical potentials of the gels in KH₂PO₄ solutions show an abrupt increase in gel potential concomitant with the mechanical softening transition. Magnetic resonance imaging experiments reveal an increase in water spin-spin relaxation time (T₂) at this range and small angle neutron scattering demonstratse a structural change at this transition, indicating increased water mobility due to a change in mesh size. This leads us to suggest additional considerations toward a more comprehensive theory of polyelectrolytes, namely ion site and affinity.