What are smart materials?
Smart materials are materials reacting to external stimulations and have one or more properties. We could also call them responsive materials. These objects can change shape or behaviors with hot water, pressure, chemical, light or heat.These smart materials could even self-assemble when you touch them. When a stimulus is applied on such an object, it is possible to transform into a brand new shape as these materials are reacting to their external environment.
Materials inspired by nature: The potential of cellulose
Researchers from the University of Bristol and the University of Bath are working on bioinspired objects. For example, they got inspired by the behavior of a pine cone in water. Indeed, submerged by water, the pine cone changes its shape and retracts itself.
For this experiment, researchers worked with cellulose. Cellulose is a really absorbent material and it is also the most abundant organic polymer on Earth. They decided to use this material able to close like the pine cone, when in contact with water, to create an ink, combining hydrogel, clay particles and cellulose pulp. This experiment leads to the creation of a smart material, able to react to stimulus.Getting inspired by nature is not a new method for researchers. It is actually called Biomimicry. This process helps us develop new materials which bring up new production possibilities.
Shape memory polymers
A shape memory polymer is a smart material offering a really large elastic deformation, in response to environmental stimuli. In order to change its shape and develop its elasticity the material has to be exposed to heat, light, electricity, moisture.These shape memory polymers are made using projection microstereolithography.
Applications of smart materials in 4D printing?
- Medical use : 3D printing is actually really helping the medical industry, and the development of bioprinting is also helping. Shape memory polymers could be inserted inside the body and react to the changes and stimulation of the body. Indeed, it could allow to create brand new antibiotics reacting, for example, to the body temperature changes.
- Improve devices for energy : A possible use of shape memory materials would be on solar panels that would be working as sensors for detecting the sun. This way, solar panels could totally be auto-rotating towards the right direction. Combined to robotics, it could allow to create solar panels totally optimized to get the maximum solar energy.
- Smart materials for construction : Combining traditional construction materials with smart material could actually be a great solution to get structures able to grow, self-repair or adapt quite quickly to their environment. That is precisely what the DARPA’s Engineered Living Materials (ELM) is looking at: using living biomaterials for architecture and construction!
- Aeronautics or automotive : Airbus SAS is starting to use a 4D-related “smart” material that reacts to temperature to cool jet engines and a wing that morphs according to aerodynamic conditions to decrease air resistance. Getting devices adapted to external condition automatically could be a major asset for many different industries.
We hope that this blog post helped you to get a better understanding of smart materials, 4D printing, and of how this technology could be useful in the future. Obviously, there are still a lot of improvements to do, but researchers seem to be quite interested in it, and the first experiments and smart materials developments are really promising!
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