A new material developed by engineers from University of Colorado Boulder that can transform itself into complex, pre-programmed shapes via light and temperature stimuli, which allows a literal square peg to morph and fit into a round hole before reverting into its original form.
This controllable shape-shifting material was described recently in the journal Science Advances. It can have broad applications such as for manufacturing, robotics, biomedical devices and artificial muscles.
“The ability to form materials that can repeatedly oscillate back and forth between two independent shapes by exposing them to light will open up a wide range of new applications and approaches to areas such as additive manufacturing, robotics and biomaterials”, said Christopher Bowman, who is the senior author of the new study and a Distinguished Professor in CU Boulder’s Department of Chemical and Biological Engineering (CHBE).
Several efforts in the past have also used a variety of physical mechanisms to alter an object’s size, shape, or texture with programmable stimuli, but such materials have historically been quite limited in terms of size and extent to which they can be changed. It has also been quite difficult to reverse back to the object’s state.
The new material developed by CU Boulder is readily programmed that allows two-way transformations on a macroscopic level with the help of liquid elastomers (LCEs), the same technology which is the basis for modern television displays. The unique molecular arrangement of these LCEs makes them susceptible to dynamic change via heat and light.
To counter this problem, the research team installed a light-activated trigger to LCE networks that can set a desired molecular alignment in advance by exposing the object to specific wavelengths of light. This trigger then remains inactive until it is exposed to corresponding heat stimuli.
As an example, a hand folded origami swan programmed in this fashion will remain folded at room temperature but when the temperature is raised to 200 degrees Fahrenheit, the swan’s shape changes into a flat sheet. Later, when the temperature is lowered to room temperature, the origami slowly regains its pre-programmed swan shape.
The ability of the material to change and reverse back to its original state makes it possible for it to have a wide range of possible applications, especially for future biomedical devices that could have the potential to 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, the 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.”