Quantized Collision/Fusion Events of Anionic Ionosomes at a Polarized Soft Micro-Interface

Graphical With single-entity collisional electrochemistry , anionic ionosomes (i. e., negatively-charged nanoscopic water clusters wrapped by an ionic bilayer) are quantitatively analysed at a positively polarized micro-water/oil interface. When Cl − -ionosomes in the organic phase collide/fuse with the polarized interface formed at the very tip of a micropipette, chloride ions will be released from an ionosome into the water phase manifested as a current spike along the timeline. Fusion mechanism along with sizing of ionosomes are readily uncovered via detailed analysis of the current spikes. Single-entity collisional electrochemistry (SECE) can capture physicochemical information at the single entity level. In the present work, we systematically studied in-situ generation and detection of single anionic ionosomes via SECE combined with a miniaturized interface between two immiscible electrolyte solutions (ITIES). Ionosome is an ionic-bilayer encapsulated nanoscopic water cluster/droplet that carries a net charge. Discrete spiky ionic currents were observed upon collisions/fusions of individual F − or Cl − -ionosomes with a positively polarized micro-ITIES. This fusion process was proved to follow the bulk electrolysis model. With this method, some essential factors such as concentration and charge density of the hydrated anions, and the interfacial area, were revealed. It demonstrates that anionic ionosomes share a common theoretical framework with their counterparts (i. e., cationic ionosomes, like Li + -ionosomes). This work will spur the advancements in a myriad of fields, including such as the colloid and interface science, micro- and/or nanoscale electrochemistry, and electrophysiology and brain sciences.