Enhancement of electrical properties of electrically conductive adhesives (ECAs) by using novel aldehydes

To improve the electrical properties of electrically conductive adhesives (ECAs), different types of aldehydes, salicylaldehyde and transcinnamaldehyde, were introduced into ECA formulations. During the curing process, the aldehydes acted as a reducing agent and reduced metal oxide in ECAs. At the same time, aldehydes could consume ambient oxygen and prevent the oxidation of the metal fillers in the ECA. The oxidation product of aldehydes, carboxylic acids with shorter molecular chains, could partially replace or remove the long chain stearic acid (C-18) surfactant on the lubricated Ag flakes and enhance the electrons tunneling between the Ag flakes in the ECAs. As such, the multiple effects of aldehydes in ECAs improved the conductivity significantly. Dynamic mechanical analysis and thermomechanical analysis studies indicated the improved performance for mechanical and physical properties of ECAs as well.