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

Abstract

Complex aqueous emulsions represent a promising material platform for the encapsulation of cells, pharmaceuticals, or nutrients, for the fabrication of structured particles, as well as for mimicking the barrier-free compartmentalization of biomolecules found in living cells. Herein, we report a novel, simple, and scalable method of creating multicomponent aqueous droplets with highly uniform internal droplet morphologies that can be controllably altered after emulsification by making use of a thermal phase separation approach. Specifically, temperature-induced phase separation inside as-formed emulsion droplets comprising aqueous mixtures of two or more hydrophilic polymers allows for the generation of Janus and Cerberus emulsion droplets with adjustable internal morphologies that are solely controlled by a balance of interfacial tensions. We demonstrate our approach by applying both, microfluidic and scalable batch production, and present a detailed model study with predictive capabilities that enables fine-tuning and dynamically altering the droplet morphology as a function of types, molecular weights, and hydrophilicities of the polymers as well as the surfactant hydrophilic-lipophilic balance. The ability to rationally design complex aqueous emulsion droplets with previously unattainable dynamic control over their morphologies after emulsification entails the potential to design new responsive soft materials with implications for a variety of applications beyond encapsulation, including the design of complex adaptive and self-regulating materials, e.g. for chemical and biological sensing applications.

Responsive drop method: quantitativein situdetermination of surfactant effectiveness using reconfigurable Janus emulsions

“…17 Owing to this unique morphological response to targeted chemical stimuli, Janus emulsions have been exploited in a number of applications, including as tunable microlenses, 18 optical waveguides, [19][20][21] scaffolds for the fabrication of anisotropic solid objects, 22,23 motile particle systems, 24,25 and as transducers and signal amplifiers in improved chemo-and biosensing platforms. [26][27][28][29] Herein, we leverage the exquisitely sensitive chemicalmorphological coupling inside Janus emulsions for the development of a new simple and broadly applicable method for the quantitative characterization of surfactants. Specifically, we monitored the morphological response of Janus emulsions comprising two immiscible oils dispersed within an aqueous surfactant solution to variations in surfactant type, concentration, ratio, and configuration, using a customized side-view imaging setup ( Fig.…”

The influence of arm composition on the self-assembly of low-functionality telechelic star polymers in dilute solutions

“…Self-organization of building blocks due to external stimuli is ubiquitous in most materials and all living organisms in nature. Inspired by this, a remarkable body of work has been performed to understand and emulate their response to temperature [1][2][3], pH [4][5][6] and light [7,8], enabling the controlled design of their structure assembly. Recent advances in polymer chemistry have led to the synthesis of various building blocks with complex architectures and functionalized properties.…”

Exploring New Horizons in Liquid Compartmentalization via Microfluidics

“…Recently, another technique for the one-step fabrication of double emulsions based on a thermal phase separation approach was introduced. 87 The researchers do not rely on a thermoresponsive polymer, but on the temperature-dependent phase separation. The phase diagram of PEG and dextran was found to be dependent on temperature.…”