Yokohama City University Shape Memory Organic Materials-University Journal Online

Yokohama City University

Professor Satoshi Takamizawa of Yokohama City University has succeeded in producing an organic compound that has a function similar to that of shape memory alloys.As a lightweight material with shape recovery, it is expected to be applied to machine parts, transitions, biocompatible materials for medical use, etc.

　Shape memory alloys have the characteristic that even if they change shape by bending, they return to their original shape by heating to a certain temperature.It has already been used for satellite antennas, medical catheters, implants (artificial tooth roots), etc.However, it is also required to discover the shape memory effect of completely different materials, such as in applications where light weight is required or when biocompatibility higher than that of metal is required.At present, it can be realized with polymer materials, but there are problems such as the fatal weakness of resilience due to heat.Organic crystals have the potential to overcome these problems, but so far no such material or guidelines for developing such materials have been found.

In 2014, Professor Takamizawa discovered an organic compound with superelastic properties, which is the key to the shape memory of metals.This time, we have succeeded in developing a newly synthesized organic material with a shape memory effect by developing this result.Furthermore, it was confirmed that the force is as strong as a shape memory alloy and can lift 170 times its own weight.As a result, it became clear that the shape memory effect can be realized even with organic substances, and it also paved the way for the development of highly practical materials that are not inferior to alloys.

Another advantage of using organic substances is that it is easy to fine-tune the characteristics by chemical treatment.In the future, we can expect that various shape memory organic materials will be developed for various purposes.