Bicontinuous emulsions stabilized solely by colloidal particles

TL;DR

This paper presents a reproducible method for creating bicontinuous emulsions stabilized solely by colloidal particles, enabling the formation of soft solid-like bijels with tunable interfaces for potential applications.

Contribution

The authors develop a reliable protocol to produce three-dimensional bijels stabilized by a single particle layer, overcoming previous laboratory creation challenges.

Findings

Successfully created reproducible bijels with a single particle layer

Demonstrated tunable interfacial separation in bijels

Confirmed bijels behave as soft solids mechanically

Abstract

Recent large-scale computer simulations suggest that it may be possible to create a new class of soft solids, called `bijels', by stabilizing and arresting the bicontinuous interface in a binary liquid demixing via spinodal decomposition using particles that are neutrally wetted by both liquids. The interfacial layer of particles is expected to be semi-permeable, hence, if realised, these new materials would have many potential applications, e.g. as microreaction media. However, the creation of bijels in the laboratory faces serious obstacles. In general, fast quench rates are necessary to bypass nucleation, so that only samples with limited thickness can be produced, which destroys the three-dimensionality of the putative bicontinuous network. Moreover, even a small degree of unequal wettability of the particles by the two liquids can lead to ill-characterised, `lumpy' interfacial layers and therefore irreproducible material properties. Here we report a reproducible protocol for creating three-dimensional samples of bijel in which the interfaces are stabilized by essentially a single layer of particles. We demonstrate how to tune the mean interfacial separation in these bijels, and show that mechanically, they indeed behave as soft solids.