Electrical Resistance of Metal Films on Polymer Substrates Under Tension

The coupling of electrical and mechanical property measurements for thin films is a relatively new area of research. It is particularly useful to know how electrical resistance could be altered with mechanical straining for flexible electronic applications. While coupled resistance measurements have been made in conjunction with tensile straining, a clear description of the measurement technique is rarely provided. Explained here is a four-point probe resistance measurement that has been incorporated into tensile straining grips for accurate and repeatable in situ resistance measurements. Also described is an analytical explanation of how to correct for constant resistances that do not change during the experiment. The new technique has been employed on Cu films on polyethylene terephthalate (PET) to illustrate its use and to discuss how resistance will recover after 24 h.