Could you imagine if the walls of your workplace could stiffen and stretch as a response to earthquakes or shifting loads? What if your water pipes at home could change their shape to accommodate the varying rates of water flows? Or what if a table could assemble itself when you touch it?

That is the idea behind 4D printing, a process where 3D-printed objects transform in response to external environmental stimuli, such as heat, wind, water, and other forms of energy. 4D creates objects that can alter their shape and perhaps even their functions over time.

Other interesting terms…

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How Does 4D Printing Work?

4D printing requires a commercial 3D printer and a smart material. A smart material can be a hydrogel or shape memory polymer. A hydrogel is a 3D hydrophilic polymer that can hold a large amount of water while maintaining its structure. A shape memory polymer, meanwhile, is a material that can return to its original shape after getting deformed. The 3D printer turns the smart material into your desired product.

4D printing uses the 3D printer to change the structure of a smart material to the user’s desired shape. An example would be 4D-printed shoes. While they may look like your typical pair of footwear, their soles follow your feet’s unique structure, making them fit you better over time.

Watch this video to learn more about how 4D printing works.

How Does 4D Printing Differ from 3D Printing?

3D and 4D printing, as you’ve seen, uses the same printer. The difference lies in the materials used to create objects. 3D printing doesn’t require smart materials that can change their shape or form over time.

Using our shoe example above, 3D-printed footwear will retain their shape no matter how often you wear them and how many years you’ve had them. They won’t fit your feet as snugly as 4D-printed shoes because the materials used to make them don’t change over time.

What Are the Benefits of 4D Printing?

4D printing can provide benefits, such as:

  • Enhancing the capabilities of printed products 
  • Designing new applications of adaptive materials
  • More efficient manufacturing 
  • Reduced manufacturing costs and carbon footprints. 

All these could be realized because the technology is characterized by:

  • Self-repair: 4D-printed plumbing pipes, for instance, can change their diameter depending on how much water flows through them. As such, they can potentially repair themselves if they crack or break because they can respond to environmental changes.
  • Self-assembly: 4D-printed building materials, which can change their shape, will take do-it-yourself (DIY) construction to the next level. Imagine being able to print custom shapes to instantly build a bridge. You won’t need to spend more on labor costs so long as the structures are deemed structurally sound by engineers.
  • Self-adjustment: 4D-printed clothes can be made of materials that adjust to the current weather or climate. Imagine how much money people would be able to save buying only a single set of clothes for all seasons.

4D-printed objects’ ability to respond to the environment will make them last more, lessening costs and carbon footprint. The objects can also be used for more applications because of their adaptability.

What Are the Potential Uses of 4D Printing?

3D printing has many exciting applications that 4D printing is taking a step higher. 4D printing uses special materials and intricate designs that can be “programmed” to stimulate a 3D-printed object to change its shape. This technology has many potential applications, particularly in the aerospace, automotive, biomedicine, and defense and military sectors.

Aerospace

In the aerospace industry, coming up with intelligent materials that can quickly react to external stimuli can be advantageous. 4D printing makes it easier to develop self-deploying structures that can aid in ventilation and engine cooling.

One project currently in the pipeline is a partnership between the Massachusetts Institute of Technology (MIT) Self-Assembly Lab and Airbus SAS. The two organizations are currently developing a 4D-printed material that can be programmed to cool engines when presented with significant temperature changes. One of the items they are looking at is an air inlet component that can change their form, depending on aerodynamic conditions to reduce air resistance. Should this project succeed, it can help astronauts with space exploration missions.

Automotive

In early 2016, German car manufacturer BMW launched a futuristic concept that included 4D-printed car components that can adapt to different environmental conditions. More recently, BMW collaborated with MIT’s Self-Assembly Lab to develop an inflatable 4D structure that can transform in response to air pressure changes. Another potential application would be in building car seats that provide adaptive support.

Biomedicine

The George Washington University research team previously developed a 4D-printable and photo-curable resin made from renewable soybean oil. This biocompatible resin changes shape when exposed to fluctuating temperatures then returns to its original state when the condition normalizes. Further studies proved that the material has potential use in human bone marrow mesenchymal stem cell growth. Researchers believe that these findings can help develop biomedical scaffolds crucial in creating functional human tissues.

Another potential application of 4D printing is in diagnosing and treating several gastrointestinal diseases. MIT researchers were able to develop a 3D printing ink infused with magnetic microparticles. When introduced into the body, these microparticles can be remotely controlled to clear blockages, get tissue samples, or deliver medications to specific injury areas.

Defense and Military

3D printing is now widely used in the defense and military sectors. And it looks like the same will hold for 4D printing. At present, researchers are looking at using 4D printing to develop more camouflage-ready military uniforms that transform into protective gear against shrapnels or poisonous gases. Another potential use has to do with building self-assembling objects like shelters or bridges for tactical missions.

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The future of 4D printing shows great promise, particularly for the manufacturing industry. Just imagine having the ability to create objects that can change shape due to different stimuli. While many of the 4D-printed technologies are still in development, we will be seeing them in use before long.