Liquid-liquid triboelectric nanogenerator based on the immiscible interface of an aqueous two-phase system

Abstract

Solid nanogenerators often have limited charge transfer due to their low contact area. Liquid–liquid nanogenerators can transfer a charge better than the solid–solid and solid–liquid counterparts. However, the precise manipulation of the liquid morphology remains a challenge because of the fluidity limits of the liquid. In this work, using the surface tension of a droplet to fix its shape, a liquid-liquid triboelectric nanogenerator in Contact-Separation mode is designed using an immiscible aqueous-aqueous interface, achieving a contact surface charge transfer of 129 nC for a single droplet. The configuration is proven to be applicable in humid environments, and the two-phase materials have good biocompatibility and can be used as an effective drug carrier. Therefore, this nanogenerator is useful for designing future implantable devices. Meanwhile, this design also establishes the foundation of aqueous electronics, and additional applications can be achieved using this route.

Tribocatalysis mechanisms: electron transfer and transition

“…Electron transfer occurs with the electron cloud overlap between two atoms/molecules, wherein the friction force determines the overlap strength. The electron transfer model can be extended to the solid–liquid, 21 liquid–liquid, 22 and liquid–gas cases. 23 For tribocatalysis, many researchers believe that the electron transfer between catalysts and environmental materials through friction enables the redox reaction to degrade organic pollutants.…”

“…The pollutants in the solution obtain electrons and undergo a reduction reaction to be degraded. Finally, triboelectric nanogenerators based on liquid–liquid and liquid–gas interfaces have been reported, 22,23 and electron transfer can occur between them. Therefore, liquid–gas and liquid–liquid interface tribocatalysis are feasible theoretically.…”

Self-Powered Electronic Skin for Remote Human–Machine Synchronization

“…At present, many research groups at home and abroad have already started research on energy harvesting and signal sensing of nanogenerators, especially in wearable flexible sensors. − By changing the structure and composition of nanogenerators, the signal monitoring of tactile pressure, physiological state, and physical environment can be realized. Under different monitoring indexes, nanogenerators can realize different state monitoring by using the particularity of their structures.…”

All-Aqueous Microfluidics Fabrication of Multifunctional Bioactive Microcapsules Promotes Wound Healing

“…Removal of the nonbiocompatible organic solvents and surfactants cannot be completely achieved and therefore could induce clinical concerns. , Therefore, novel techniques are highly desirable for developing organic solvent-free and biocompatible microcapsules with controllable morphology, efficient drug encapsulation, and whole-stage therapeutic effects. We have previously developed an all-aqueous microfluidic approach to generate water-in-water emulsion droplets with controllable sizes and architecture. ,− All-aqueous systems eliminate the use of organic solvents to advance the biocompatibility of the prepared emulsions. By acting as organic solvent-free templates for fabrication of biocompatible microparticles, capsules, colloidosomes, and fibers, the all-aqueous emulsions hold great promise for developing multifunctional biomaterials for wound treatment. ,, …”