Ion emission from nanodroplets undergoing Coulomb explosions: a continuum numerical study

A droplet charged above the Rayleigh limit is unstable. In resulting dynamical process, referred to as a Coulomb explosion, smaller droplets with higher charge-to-mass ratios are ejected, reducing charge of parent below limit. Furthermore, if sufficiently small, electric field on its surface can promote ion emission. Ion emission lower spherical limit, keeping it stable, or reduce deforming droplet, changing dynamics and potentially preventing explosion. This article develops continuum phase electrohydrodynamic model study interplay between explosions emission, using nanodroplets ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-Im) case study. small (diameter $D \lesssim 20$ nm for EMI-Im), strong enough emit ions in early droplet's evolution, suppressing For $20 D 45$ nm, EMI-Im may not significant emission; however, unstable becomes ellipsoidal, emitted from vertices, ultimately explosion while shedding $20\unicode{x2013}40\,\%$ initial charge. larger droplets, $45 100$ evolution typical observed, accompanied by which however insufficient prevent progeny account $24\,\%$ $16\,\%$ charge, respectively.