Programmable materials are true shape-shifters. They can change their characteristics in a controlled and reversible way with the push of a button, independently adapting to fit new conditions.
Researchers at the Fraunhofer Cluster of Excellence Programmable Materials (CPM), which is formed of six core institutes, have developed such materials. Fraunhofer CPM plans to bring them to the market with the help of industry partners.
Many people across the world are bedridden—due to illness, an accident, or old age—and they often end up with painful bedsores. Programmable materials can be used to make mattresses that prevent bedsores. So, how can they be programmed?
“Essentially, there are two key areas where adjustments can be made: the base material—thermoplastic polymers in the case of mattresses and metallic alloys for other applications, including shape memory alloys—and, more specifically, the microstructure,” explained Heiko Andra, spokesperson on the topic at the Fraunhofer Institute for Industrial Mathematics ITWM, one of the core institutes. “The microstructure of these metamaterials is made up of unit cells that consist of structural elements such as small beams and thin shells.”
The size of each unit cell and its structural elements in conventional cellular materials such as foams vary randomly. The cells in programmable materials are also variable but can be precisely defined, that is, programmed. This programming can be made, for example, in such a way that pressure on a particular position will result in specific changes at other regions of the mattress, that is, the size of the contact surface can be increased to provide optimal support to certain areas of the body. Areas of the bed that experience more pressure are automatically made softer and more elastic. Caregivers can also adjust the ergonomic lying position to best fit their patient.
The change in shape that the material should exhibit and the stimuli to which it reacts—mechanical stress, heat, moisture, or even an electric or magnetic field—can be determined by the choice of material and its microstructure.
The initial pilot projects with industry partners are already under way. The research team expects programmable materials to initially act as replacements for components in existing systems or be used in special applications such as medical mattresses, comfortable chairs, variable damping shoe soles, and protective clothing. “Gradually, the proportion of programmable materials used will increase,” said Andra. Ultimately, they can be used everywhere, from medicine and sporting goods to soft robotics and even space research.