Size effect of ligaments on charge induced surface stress response of nanoporous Pd prepared by dealloying

Nanoporous Pd with different ligament widths (w) were prepared by dealloying and subsequent thermal coarsening. The electrocapillary coupling parameter zeta, which is usually used to quantify the charge induced surface stress response, of the as-prepared samples was measured by an in-situ dilatometry method. It is found that when w is smaller than a critical value w(crit) = 49.0 +/- 7.4 nm, influenced by the size effect of ligaments, the absolute value of zeta increases from 0.76 V to 1.03 V by decreasing w from 49.0 +/- 7.4 nm to 112 +/- 1.4 nm; while w > w(crit) the size effect of ligaments on zeta becomes negligible. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.