Shape-shifting LCE/PS material eyes medical applications

Researchers at Rice University have developed a material that changes shape in a predetermined pattern when heated and reverts back to its original form when cooled. Applications for the biocompatible liquid crystal elastomer (LCE) layered with a thin strip of polystyrene (PS) include dynamic substrates for cell cultures and implantable products that are designed to contract and expand in response to stimulus.

The polystyrene layer that is bonded to the LCE is what enables the unique shape-shifting properties. Without it, the LCE would simply expand or contract along its nematic axis when heated. The stiffer PS layer produces a more elaborate choreography, causing the material to wrinkle, bend, or fold. A video shows the material in action.

Configurations are designed into the material by applying parameters such as the shape and aspect of the LCE, the thickness and patterning of the PS, and the temperature at which the PS is applied. Researchers say that there is no limit to the complexity of the shapes that can be teased from the material by playing with the patterning. 

Unlike shape-memory polymers that only change shape once, LCEs are reversible, says Rice University polymer scientist Rafael Verduzco, who is quoted in a press release posted on the university website. This gives them great potential for biological applications, he adds. 

The research is published in the journal Soft Matter.