One-Step Formation of W/O/W Multiple Emulsions Stabilized by Single Amphiphilic Block Copolymers

Abstract

Multiple emulsions are complex polydispersed systems in which both oil-in-water (O/W) and water-in-oil (W/O) emulsion exists simultaneously. They are often prepared accroding to a two-step process and commonly stabilized using a combination of hydrophilic and hydrophobic surfactants. Recently, some reports have shown that multiple emulsions can also be produced through one-step method with simultaneous occurrence of catastrophic and transitional phase inversions. However, these reported multiple emulsions need surfactant blends and are usually described as transitory or temporary systems. Herein, we report a one-step phase inversion process to produce water-in-oil-in-water (W/O/W) multiple emulsions stabilized solely by a synthetic diblock copolymer. Unlike the use of small molecule surfactant combinations, block copolymer stabilized multiple emulsions are remarkably stable and show the ability to separately encapsulate both polar and nonpolar cargos. The importance of the conformation of the copolymer surfactant at the interfaces with regards to the stability of the multiple emulsions using the one-step method is discussed.

Synthesis of Oil-Laden Poly(ethylene glycol) Diacrylate Hydrogel Nanocapsules from Double Nanoemulsions

“…[33][34][35][36][37] While microcapillary-based methods offer precise control over droplet sizes and distribution, they have low throughput (typically less than 1 mL/hr for a single device 38 ), and device limitations make nanoscale droplet production infeasible without significant technological advances. On the other hand, bulk emulsification has been used to successfully form nanoscale multiple emulsions, but is significantly more difficult to control, typically resulting in a large dispersity of both size and morphology.…”

Biocompatible Stimuli-Responsive W/O/W Multiple Emulsions Prepared by One-Step Mixing with a Single Diblock Copolymer Emulsifier

“…This emulsifier can be a diblock copolymer [15][16][17][18] as well as some nanoparticles [19][20][21] . Hanson et al were the first to obtain long-term stability W/O/W emulsions stabilized by a diblock polypeptide 15 .…”

Stability and rheology of W/Si/W multiple emulsions with polydimethylsiloxane

“…Pickering emulsions with graphene oxide (GO) as a stabilizer had been prepared and the effects of the type of oil, the sonication time, the GO concentration, the oil/aqueous rate, and the pH value on the stability, type, and morphology of the systems were investigated [24]. And multiple emulsions with different oils including camelina, fish, camelinae and fish oil blends and lipophilic polyglycerol polyricinoleate (PGPR) and hydrophilic sodium caseinate (SC) as emulsifiers had also been investigated [25].…”

“…However, the stable of multiple emulsions still unsettled, whether prepared by two-step or single-step emulsification with different emulsifiers and oils [24][25][26].…”