Electrically Detachable Ionic Conductive Epoxy Adhesives with High Bonding Strength

Detachable adhesives are considered to be an essentialstrategyto realize reuse and recycle of the bonded components, but it is agreat challenge to fabricate a detachable adhesive with ultra-highbonding strength. In this study, electrically detachable ionic conductiveepoxy adhesives (IEPs) are prepared through introduction of poly(ethyleneglycol) (PEG) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([BMIM]TFSI) into epoxy. It is found that an initial bonding strengthof more than 20 MPa can be realized via adjusting the PEG molecularweight due to the stronger crystallization tendency of PEG with ahigher molecular weight that shows remarkable reinforcement and strengtheningeffect. In spite of the ultra-strong bonding of the IEPs, they canbe completely and automatically detached by applying 60 V DC voltagewithin 1 min. The electrically detaching mechanisms of IEPs are furtherstudied and it is confirmed that the electrically detaching behavioris dependent on the electrodecomposition of ionic liquids; thus, theelectrodecomposition mechanism of [BMIM]TFSI and the impacts on bondingsubstrates are presented. It is believed that this work provides aneffective strategy for developing electrically detachable adhesiveswith ultra-high initial bonding strength.