The Metal/Liquid Interface: the Charge Injection Process

An attempt has been made to analyze the experimental observations published over the past years on charge injection into liquids, and to examine the criteria developed for charge injection into vacuum or gases as to their applicability to liquids. It was concluded that the emission sites on metal cathodes are smaller than originally assumed. The Fowler-Nordheim or modified Schottky emission laws do not define uniquely either the emission area, the local field enhancement, or the prevailing work function. Experimental studies reported here suggest these submicroscopic sites to be either grain boundaries, protrusions of molecular dimensions, or minute dust particles. Apparently only a few of these sites actually emit electrons at any instant of time.