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Four dimensional printed structures may enable new generations of soft robotics, implantable medical devices and consumer products.

UT-Dallas and Pitt Collaborate on 4D Printing Breakthrough

Four-dimensional (4D) printing is a term that describes additive manufacturing of stimuli-responsive materials. This process results in three-dimensional structures capable of morphing between predetermined shapes after printing.  Previous material strategies require mechanical programming to achieve shape change or required that the material operate in water, however in this new publication, “Four-dimensional Printing of Liquid Crystal Elastomers” University of Pittsburgh Professor Ravi Shankar worked in partnership with UT Dallas faculty (Taylor H. Ware) and students (Cedric P. Ambulo, Julia J. Burroughs, Jennifer M. Boothby, Hyun Kim) demonstrate a platform for programming the molecular-level order in macroscopic 3D structures. 

Their idea centers on aligning liquid crystal elastomers by controlling the print path during printing, whereby 3D structures with locally controlled and reversible stimulus response can be fabricated into geometries not achievable with current processing methods.  Having been published in October 2017, this publication has achieved recognition from numerous research peers as being “first of its kind”, has been awarded the best poster award by the International Liquid Crystal Elastomer Conference 2017, and currently has a patent application pending. 
LCEs are a class of stimuli-responsive polymers that undergo large, reversible, anisotropic shape change in response to a variety of stimuli, including heat and light. Unlike many materials that undergo reversible shape change, these materials require neither external loads nor aqueous environments. The UT-Dallas/Pitt team also exploited this platform to create structures, which can snap between discrete geometries by exploiting snap-through instabilities. Snap-through instabilities have been observed in nature (e.g. Venus flytrap, Hummingbird’s beak..) to magnify the power density and speed of actuation. Utilizing similar ideas, this team showed how 3D printed, molecularly-ordered structures can snap between shapes and generate large actuation power-densities in response to an ambient stimulus (e.g. heat, light, solvent, etc.). Such actuators make ideal candidates for applications, including soft robotics, biomedical implants, adaptive optical structures etc.

This material is based upon work partially supported by the Air Force Office of Scientific Research under award numbers FA9550-17-1-0328 and FA9550-14-1-0229." "Any opinions, finding, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the United States Air Force."

Author: Elizabeth Allison