You may have heard of 3D printing already – after all, it’s not a completely new concept (in fact, it’s more than 30 years old), using additives to print physical objects. That’s exactly what 4D printing is. It adds the dimension of transformation over time, so although it may start life as a physical object, such as a computer component, a prosthetic limb or any other physical thing, adding in a fourth dimension, such as an environmental condition, it can change its form and purpose autonomously.
The difference between 3D and 4D printing is in the material in the method. In some applications, using a specific material, such as shape memory alloy can be used, with temperature changing the shape of the item. These can be printed in exactly the same way as 3D printed goods, but if the temperature hits a certain level (either higher than – or lower than – the material’s operating temperature).
Other materials that can be used to create 4D printed objects that change over time are electroactive polymers, pressurized fluids or gasses that can change when environmental conditions change, such as exposure to certain light sources or humidity levels.’
The use cases for 4D printing are pretty varied, especially in the medical field where the methods could be used to create prosthetic limbs that change according to touch, a medication that activates when swallowed (triggered by stomach acids, body temperature or moisture) or stents that open up blood vessels when they reach their destination.
Other applications for 4D printed materials that have already been developed are water valves printed from a hydrogel that open and close when the temperature of the water changes, shoes that change shape with your feet and clothing that changes composition (for example, adds a waterproof layer) when exposed to different types of weather.
4D printed materials could also be used in transport, for example, changing the outer layer of an aircraft when it reaches certain air temperatures or allowing a car to operate non-mechanically when exposed to electrical currents. In the end, it makes me think about that HBO TV shows, Westworld…