Chinese scientists develop shape memory polymer with delayed recovery onset

HANGZHOU -- Chinese scientists have developed a memory material capable of delayed deformation following a trigger, ushering in new prospects for applications in biological devices, soft robotics, aerospace structures and flexible electronics.

The shape-shifting hydrogel described in a study published this week in the journal Nature is shown to undergo shape transformation at natural ambient temperature, with a recovery onset delay of up to 46 minutes.

The delay durations are programmable, which offers a unique mechanism for shape-shifting control, according to the researchers from Zhejiang University.

A delayed transformation is desirable since certain shape-shifting polymers rely on naturally present stimuli as triggers, like human body temperature, but their transformation timings are hardly controllable, forming a bottleneck for the application of implantable devices.

In the study, the researchers demonstrated a four-dimensional printed intravascular stent that shifted shape at a certain time after it was brought into the targeted place in a blocked blood vessel.

The naturally triggered shape-memory polymer with a tunable recovery onset can markedly lower the barrier for device implementation, according to the researchers.