Batch-Scale Preparation of Reverse Janus Emulsions

Abstract

A strategy is proposed to produce novel (W1 + W2)/O reverse Janus emulsions in batch scale simply by one-step vortex mixing. Aqueous two-phase systems (ATPSs), i.e., two immiscible aqueous phases dominated by sodium carbonate and ethanol, respectively, are employed as inner phases and vegetable oil (VO) as continuous phase. The geometry of the Janus droplets, although formed as a result of a kinetic process, is tunable and controllable easily by adjusting the composition of ATPSs based on three-phase diagram. Reducing the relatively higher water/oil interfacial tensions to a comparable value of water/water interface, which is extremely low in order of 0.1 mN/m, is achieved by employing a fluorocarbon surfactant. Moreover, the weak acid-induced deprotonation of the fatty acid in the VO phase due to the presence of sodium carbonate also contributes to the lower water/oil interfacial tension. The total free-energy values calculated verify the overwhelmingly favored Janus geometry, which indicates that this topology is heavily preformed as local equilibrium state. The approach proposed provides vehicle for the synthesis of aqueous-based materials with various advanced morphologies.

From shaping to functionalization of micro-droplets and particles

“…[34][35][36] Various shapes and complexities of the droplets have been designed by manipulating the chemical composition, volume ratio, as well as the number of the mixed solutions. [37][38][39] One-step vortex mixing, the simplest type of emulsication on a batchscale, was introduced to produce Janus emulsions by Friberg et al and Guo et al (Fig. 2A).…”

“…By precisely adjusting the volume ratio of two oils and surfactant concentration, the anisotropic geometry, such as snowman and dumbbell shapes, and the size of Janus droplets could be designed. [37][38][39]41,42 The Cerberus droplets were produced by mixing three mutually immiscible oils with surfactants in aqueous solution (Fig. 2B(i)).…”

Synthesis of Polymeric Janus Superstructures via a Facile Synthesis Method

“…While various authors have reported in detail the structural transitions of emulsions through interfacial tension data, the meta‐state of a JCS has not yet been observed in their studies. [ 33,34 ] Such multicompartment structures can allow for the encapsulation of multiple drugs in separate compartments within a JCS.…”

Responsive Janus and Cerberus emulsions via temperature-induced phase separation in aqueous polymer mixtures

“…37 Alternative current approaches for the production of complex aqueous emulsions are based on a triggered coalescence of droplets by overcoming of the droplet stabilization potential, e.g. by shearmixing of phase separated aqueous polymer mixtures, 38 or rely on externally triggering a polymer phase-separation inside as-formed emulsion droplets. To this end, an induced mass transfer from the dispersed phase, e.g.…”