Shape-Shifting Material Morphs, Reverses Itself Using Heat, Light

Credit: University of Colorado Boulder

Previous efforts have used a variety of physical mechanisms to alter an object’s size, shape or texture with programmable stimuli. However, such materials have historically been limited in size or extent and the object state changes have proven difficult to fully reverse.

The new CU Boulder material achieves readily programmable two-way transformations on a macroscopic level by using liquid crystal elastomers (LCEs), the same technology underlying modern television displays. The unique molecular arrangement of LCEs make them susceptible to dynamic change via heat and light.

Credit: University of Colorado Boulder

To solve this, the researchers installed a light-activated trigger to LCE networks that can set a desired molecular alignment in advance by exposing the object to particular wavelengths of light. The trigger then remains inactive until exposed to the corresponding heat stimuli. For example, a hand-folded origami swan programmed in this fashion will remain folded at room temperature. When heated to 200 degrees Fahrenheit, however, the swan relaxes into a flat sheet. Later, as it cools back to room temperature, it will gradually regain its pre-programmed swan shape.

The ability to change and then change back gives this new material a wide range of possible applications, especially for future biomedical devices that could become more flexible and adaptable than ever before.

“We view this as an elegant foundational system for transforming an object’s properties,” said Matthew McBride, lead author of the new study and a post-doctoral researcher in CHBE. “We plan to continue optimizing and exploring the possibilities of this technology.”Contacts and sources:’
Trent Knoss
University of Colorado Boulder