Ionic and adhesive triboelectric elastomer for normalizing charge polarity and density of contact electrification with general material

Contact electrification (CE) is widely applied in microscale energy harvesting and active sensing. However, the CE results vary in charge density and polarity between different materials, while the preexisted charges on the surface make the CE process more unpredictable. Here, an adhesive triboelectric elastomer (ATE) is synthesized by combining the ionic liquids (ILs) and pressure-sensitive adhesive (PSA) to generate normalized charge polarity and density by CE. The ILs neutralize the preexisted charges on the targeted surface. Then, the adhesion groups of PSA bond to targeted surface and trigger the heterolytic cleavage, leaving negatively charged fragments on the targeted surface. This ATE is capable of generating stable charge density (-50 to -70 microcoulombs per square meter) on almost all the commonly used triboelectric materials, irrespective of the preexisted charges on the surface. The stable and normalized CE effect benefits all the triboelectric sensors and enables special functions, and this ATE design also deepens the understanding of CE and interface science.