Ultra-Strong Ionogel Adhesives via in situ Microphase Separation

Abstract

Ionogels hold great promise due to their numerous charges and abundant polarities, which facilitate strong interfacial interactions with substrates. However, the plasticizing effect of ionic liquid weakens their mechanical properties, limiting the adhesive performance of ionogel adhesives. Developing high-strength ionogel adhesives, therefore, remains a significant challenge. In this work, an exceptional ionogel adhesive is achieved by copolymerizing methyl methacrylate (MMA) and acrylic acid (AA) in 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide (EMITFSI). The distinct solubilities of the polymers in this ionic liquid result in in situ microphase separation. This novel ionogel exhibits an ultrahigh adhesion strength, with a lap shear strength of 13.41 MPa on glass, surpassing most values reported to date. The remarkable properties of this ionogel are primarily attributed to microphase separation, which enhances adhesion through the arrangement of hydrogen bonds at the interface and improves cohesion by dissipating energy within the bulk. This study offers promising prospects for the design and application of high-performance ionogel adhesives.