HEMI Seminar: Michael Dickey, Dept. of Chemical and Biomedical Engineering, NC State University

Soft, Stretchable, and Reconfigurable Materials for Electronics and Actuators

Michael Dickey, Dept. of Chemical and Biomolecular Engineering, NC State University

This talk will describe efforts in our research group to control the shape and function of soft materials (liquid metals, polymers and hydrogels) for applications that include stretchable electronics, soft robots, and self-folding polymer sheets. The research harnesses interfacial phenomena, micro fabrication, patterning, and thin films. The talk will discuss the underlying fundamental science motivating active areas of research in our group, which include:

• Ultra-stretchable wires, sensors, antennas, and microelectrodes composed of liquid metal alloys based on gallium. The metal is a liquid at room-temperature with low-viscosity (water-like) and can be micromolded due to a thin, oxide skin that forms rapidly on its surface. The metal can be patterned in a number of ways including injection into microchannels or by direct-write 3D printing. Recently, we discovered that the oxide may be the best surfactant ever reported and can be removed or deposited using electrochemistry in electrolyte as a new method to control the shape of the metal.
• Self-folding polymers sheets that change shape in response to light. These sheets are a form of shape memory polymers that are compatible with 2D patterning techniques including lithography, inkjet printing, and roll to roll processing.   The appeal of this work is converting 2D patterns into 3D shapes (similar to origami) in a hands free manner.
• New methods for patterning ions in hydrogels. This reversible process can imprint topography in the hydrogel using modest voltages, tune its local mechanical properties to create physically-reinforcing exoskeletons, and generate stresses sufficient to actuate or fold hydrogels over large distances within seconds.

Seminar will begin at 3:30 PM in Malone Hall, G33/35.

Top: 3D printed liquid metal microstructures, Bottom (L to R): Gel patterned with ions, self-folding polymer sheets, stretchable antennas composed of liquid metal in microchannels