“We’ve created a memory device with the physical properties of Jell-O,” says  Dr. Michael Dickey, assistant professor of chemical and biomolecular engineering at NC State and co-author of a paper describing the research.

Researchers have created a memory device with the physical properties of Jell-O, and that functions well in wet environments.

Conventional electronics use rigid, brittle materials and are averse to wet environments. “Our memory device is soft and pliable, and functions extremely well in wet environments – similar to the human brain,” Dickey says.
Below photo credit: Michael Dickey, NC State University.

Prototypes, not yet  optimised to hold significant amounts of memory, work well in environments hostile to traditional electronics and made using a liquid alloy of gallium-indium (GaIn) metals set into water-based gels used in biological research.

The device ability to function in wet environments and the biocompatibility of the gels, means  technology interface promised between electronics with biological systems – as cells, enzymes or tissue.

“These properties may be used for biological sensors or for medical monitoring,” Dickey says.

Devices function like the “memristors," vaunted as a possible next-gen memory technology. The “mushy” memory device components have two states: one conducts electricity, one does not.

These can be used to represent binary 1s and 0s with the mushy memory using charged ion molecules to do the same thing.

In the memory device’s circuits, the metal alloy is the circuit’s electrode and sits on either side of a conductive piece of gel. When the alloy electrode is exposed to a positive charge it creates an oxidized skin making it resistive to electricity. Call that the 0. When the electrode is exposed to a negative charge, the oxidized skin disappears, and it becomes conducive to electricity. Call that the 1.

Normally, when a negative charge is applied to one side of the electrode, the positive charge would move to the other side and create another oxidized skin – meaning the electrode would always be resistive.

To solve that researchers “doped” one side of the gel slab with a polymer that prevents the formation of a stable oxidized skin. That way, one electrode is always conducive,  giving the device 1s and 0s it needed for electronic memory.

“Towards All-Soft Matter Circuits: Prototypes of Quasi-Liquid Devices with Memristor Characteristics,” Advanced Materials.  Co-authors Hyung-Jun Koo and Ju-Hee So, and INVISTA Professor of Chemical and Biomolecular Engineering Orlin Velev.

The research was supported by the National Science Foundation and the U.S. Department of Energy. The Department of Chemical and Biomolecular Engineering
is part of the university’s College of Engineering.