Studies of the effect of mechanical deformation or loading conditions oil the electronic work function (EWF) are of both fundamental and practical importance. This is especially emphasized by the recent applications of the Kelvin probing technique to investigate mechanical and electronic behavior of nanomaterials. However, the physical mechanism responsible for such effect has not been understood well. In this study, changes in EWF of metals and alloys under simple and complex loading conditions were tested using a Kelvin probe. It is demonstrated that both strain and strain rate can decrease the EWF. which is consistent with the previous experimental observations using the different measurements Furthermore. the EWF increased during uniaxial tension and decreased during uniaxial compression, whereas the EWF was relatively stable in the case of combined tension-compression loading. The above experimental results therefore indicate the important role of dislocations in deformation and the resultant electronic response. (c) 2009 Elsevier B.V. All rights reserved.