Membrane technology inspired by milk reaction could revolutionize wearables

This simple, yet effective process can rapidly create 2D ionogel membranes which could be used in batteries and wearable tech.
Amal Jos Chacko
Wearable tech.jpg
Wearable tech.


From velcro to sonar to solar cells, many ground-breaking inventions have come to be with their makers inspired by nature. A team of researchers led by engineers at the University of Texas at Austin has found inspiration in a milk reaction to create a flexible gel film that could trigger innovations in sensors, batteries, robotics, and more.

Milk, when heated, tends to form a skin-like layer made of denatured proteins and fat at the top. ”We were inspired by this phenomena and explored it in different materials to produce multifunctional gel membranes that are easy to separate,” said Guihua Yu, a professor in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering and Texas Materials Institute, who specializes in material science.

These gel membranes are similar to hydrogels, both polymer networks surrounded by liquids. While water is the liquid element in hydrogels, the newly developed membranes contain ionic liquid, hence the name Ionogels.

Membrane technology inspired by milk reaction could revolutionize wearables
An illustration featuring molecular arrangements at different stages of the process.

Dip and Peel with tweezers

Ionogels exhibit a more flexible structure, with the ions afforded more room to move about, making them highly conductive and very sensitive.

These properties make Ionogels prime candidates to be sensors especially to track motion, heartbeat, and other health-related parameters in wearable electronics.

The team of researchers, which includes collaborators from Northeast Forestry University and the Shenyang University of Chemical Technology in China, observes the potential for these membranes to serve as electrolytes in solid-state batteries too.

By dipping sustainable biomass materials in certain solvents in a “dip-and-peel” process, their molecules rearrange themselves into thin films at the edge of the material, creating two-dimensional ionogel membranes that can be removed easily with a set of tweezers.

This process works on different materials, and its lower cost allows it to be scaled at high speed. Additionally, the process can be tweaked to thicken or thin the film as required.

“This simple yet effective solvent-induced self-assembly method really allows rapid, and scalable production of 2D functional polymer films from different sustainable biomass materials including cellulose, chitosan, silk fibroin, guar gum, and more,” said Nancy (Youhong) Guo, one of the lead authors on the paper, formerly a graduate student and now a postdoctoral researcher at MIT.

The team now looks to fine-tune the process toward optimizing mechanical properties for applications catering to advanced technologies such as wearable electronics, robotics, and artificial intelligence.

The research is published in the peer-reviewed scientific journal Nature Synthesis.

Study Abstract

Two-dimensional (2D) ionogel membranes have emerged as a promising class of materials for broad applications in flexible electronics, smart robotics and artificial intelligence. However, the rapid, reliable and reproducible fabrication of ionogel membranes remains challenging due to difficult-to-control molecular behaviour. To overcome this challenge, we propose a ‘dip and peel’ strategy to exfoliate 2D ionogel membranes from a biomacromolecular gelatum (for example, a cellulose ionogel colloid) by controlling the solvent-induced supramolecular self-assembly. This strategy enables the simple and rapid fabrication of ionogel membranes with tunable shapes, controllable thicknesses, high ionic conductivity up to 14.1 mS cm−1, good stretchability exceeding 130% and excellent tandem duplication over 700 times. We further extend this strategy to fabricate different ionogel membranes from various biomacromolecules, including silk fibroin, chitosan and guar gum. Our results shed light on exploration of fundamental macromolecular interactions and provide an effective approach to prepare 2D biomacromolecular ionogel membranes with advanced functionalities.

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