The material does the job: Carl de Smet has developed a chair from "Shape Memory Polymers" that unfolds itself by heating it.

Stylepark Interzum
A chair reveals itself

From programmed wood via blossoming surfaces to self-assembling furniture: 4D printing promises magic potential.
by Franziska Eidner | 5/8/2017

At the latest since the process was first mentioned last year in the “Gartner Cycle for Emerging Technologies”, a kind of trend gauge for the IT sector, 4D printing has been considered the “next big thing”. And research into is is progressing not just at the Self Assembly Lab at the Massachusetts Institute of Technology (MIT), whose director Skylar Tibbits is considered the inventor of 4D printing. In Singapore, Hanover and Stuttgart research groups are busy printing in the fourth dimension. So what exactly does the idea involve? And what application potentials are there for architecture and design?

Change as the agenda

The fourth dimension actually first comes into play after the printing process proper and stands for the time factor. In 4D printing, using a 3D printer objects are made where under the influence of water, temperature, light or magnetic fields they change their outer appearance or functions: They start to develop of their own accord, as it were, to bend or to fold inward. The potential for change is “imprinted” into them using a specific material.

With "shape memory effect": polymers react to external influences such as heat or moisture and transform 3D-printed objects as shown in the project (video) "expanding lattice", a research collaboration between the Singapore University of Technology and Design, Georgia Institute of Technology, the Xi 'An Jiaotong University and Zhejiang University.

This is possible because in the 3D printing process different layers of materials are combined that allow this subsequent transformation of the object. The magic potential stems above all from the possible combinations and transformability of the materials used. Researchers have focused on the “programmability” of the changes in shape or function. Using a 3D printer, for example, shape-memory plastics that each possess different mechanical properties can be combined in a single object. Because they respond at different speeds to heat, for example, certain motion sequences or shape changes can be preset, in other words programmed.

Blossoming 4D printing

The latest results of studies conducted by a research team at the Georgia Institute of Technology, the Singapore University of Technology and Design and the Zhejiang University illustrate this superbly. Using grid structures or blossoms they show how rigid, “n-memory” plastics can be combined with shape-memory polymers, showing how 4D objects fold inwards or unfold depending on the temperature.

The nature as a rolemodel: The researcher oft the Wyss Insitute of the Harvard University print orchid-shaped structure with a hydrogel composite ink containing aligned cellulose fibrils, which enables anisotropic swelling.

A similarly impressive effect was achieved by researchers at the Wyss Institute at Harvard University using a hydrogel composite with cellulose fiber elements. On contact with water, the flat object morphs into an orchid bloom. The researchers make use here of the properties of natural fibers, having first used a complex mathematical model to compute how the fibers would swell in water which enabled them to inject the later shape change during the 3D printing process.

The Big Picture

4D printing combines the potential of additive, computer-supported manufacturing with the dynamic properties of so-called programmable materials, hydrogels and shape-memory plastics. This could in future save production, packaging, transportation and operating costs, while rendering the use of individual components of a product or system, such as additional electronics, superfluous. Moreover, components or implants could be created that individually adapt or adjust optimally to external circumstances.

“Work on shape memory plastics, alloys or hydrogels did not first start with Skylar Tibbits at MIT inventing the term back in 2013 and presenting it to great effect at TED conferences,” says Berlin-based materials expert Sascha Peters. “However, the application of such materials in 3D printing it new. What Tibbits has achieved with his Self Assembly Lab is to attract world-wide attention and establish a catching marketing label for a complex research field. Great visions are associated with 4D printing, even if it will be at least another decade until we see products ready for market and actual applications in interior design and architecture in particular.”

Peters believes the greatest potential for applications is in the auto and aerospace industries as well as in medicine. Firm collaborations are already in place here: the “Self Assembly Lab” is already working, among other things, on shape-changing car body parts or wings made of carbon fibers that change shape depending on the weather. The Laserzentrum Nord in Hanover has used 3D printing to manufacture a “cochlear” implant made of shape memory alloys that first assumes its final shape when inserted into the ear in response to the body temperature.

Moving Tree: Self Assembly Lab/MIT together with the Institute for Computational Design (ICD) of the University of Stuttgart, has printed a wood veneer that changes itself independently and in a controlled way.

Studies with programmable wooden granules conducted jointly by the Self Assembly Lab, Stuttgart’s Institute for Computional Design (ICD) and Swiss designer Christophe Guberan are interesting as regards architecture and design. A few years ago, the ICD was inspired by the behavior of pine cones and in the metro-sensitive “HygroSkin Pavilion” it developed a wooden veneer ensures the ambient temperature adapts naturally to different types of weather. In design, the composite wood veneer means you are limited by the natural properties of the wood. Far more variations are possible with elements developed by ICD together with MIT using internally-developed programmable wooden granules and 3D printing.

With their “Active Woods Products” series, the researchers also indicate what other possible applications there are for wooden design objects. The work and time-intensive processes associated with traditional steam bentwood methods could become superfluous. The researchers believe it is conceivable that a 3D printer will convert the programmable wooden granules into flat objects ready for transport that first assume their final, complex shape on being unpacked at home, thanks to the influence of moisture.

Smart wood from the printer

Other studies by the “Self Assembly Labs” envisage similar application scenarios, such as a self-unfolding table with smart, pre-tensioned textiles and a self-assembling chair: the study developed with molecular biologist Arthur Olson is entitled “Fluid Assembly: Chair Test”. However, this scenario only seems really sensible for people who own their own pool, as you do need quite a lot of water to get the chair to self-assemble.

Auto-Designed: Just as this thread twists in the water bath itself, so could furniture do when unpacking them at home in the opinion of the researchers of the Self Assemly Lab/ MIT, who for the project "4D Printing: Multi-Material Shape Change" teamed up with the companies Stratasys and Autodesk.

Belgian designer Carl de Smet’s “Popcorn furniture”, which caused such a stir at the 2013 Salone del Mobile in Milan, offers a more practical alternative. His seating (it is made of a shape memory plastic foam he developed that possesses precisely such a self-assembling effect) responds to heat and only a hair drier was required to heat them into shape. However, they are not yet on the market. De Smet produced his first arm-chair prototypes with injection molding, and is currently busy developing a printable foam.

Materials expert Sascha Peters does not think printing complete furniture items offers the greatest potential applications for 4D printing for interiors. He believes that role goes above all to surface coatings, such as foils that can turned into 3D patterns after printing. As regards 3D surfaces, what the market has to offer can be explored at the Interzum trade fair in Cologne in Hall 10.2. at the special themed area on “Digital 3D Surfaces”.

Furniture production Interiors
Koelnmesse, Cologne
16. - 19. May 2017

Self-assembly effect: The "Popcorn chair" with "Shape Memory Polymer" by the Belgian designer Carl de Smet unfolds by itself.
Inspired by pine cones: The "HygroSkin Pavilion", developed by the ICD, can be adapted to different weather conditions using metrosensitive wood veneers.