One of the primary ecological concerns of our time is plastic consumption and waste. Of the plastic we use on a day-to-day basis, less than 10% is recycled, with the rest going into landfills and, as it becoming increasingly clear, the ocean. In addition to curbing plastic consumption and reducing what we use, there is also a growing effort to find sustainable alternatives to the ecologically taxing material. One such effort is coming out of MIT, where the Mediated Matter lab is developing a technology for 3D printing water-based biopolymer composites.
The project is called Aguahoja and consists of using a robotic 3D printer to build up structures from environmentally friendly and naturally derived biopolymer composites. The materials in question are based on some of the most abundant materials on Earth, found in trees, insect exoskeletons, apples and bones. They are: cellulose, chitosan, pectin and calcium carbonate.
These natural materials have been adapted by the MIT researchers, being combined and compounded with high spatial resolutions to create highly tunable, biodegradable composites.
“Derived from organic matter, printed by a robot, and shaped by water, Aguahoja points towards a future where the grown and the made unite,” the MIT Mediated Matter Group writes. “It embodies the Material Ecology design approach to material formation and decay by design, as well as the realization of the ancient biblical verse ‘from dust to dust’―from water to water.”
The Aguahoja project presently consists of the Aguahoja I pavilion, which was unveiled in February 2018 at the MIT Media Lab Lobby. The next installation, Aguahoja II, is currently in development and will be presented starting May 10, 2019 at the Cooper Hewitt, Smithsonian Design Museum.
The impressive Aguahoja I pavilion stands at five meters tall and is made up of the tunable biocomposites and a substructure 3D printed by Stratasys. The 3D printed biomaterials all vary in stiffness, flexibility and opacity and create a “structural skin” for the installation. The continuous construction method employed in creating the structure was modeled after human skin, “with regions that serve as structure, window and environmental filter.”
In line with the project’s ecological ethos, the Aguahoja I is a temporary installation, as it can be programmed to degrade in water when it is no longer needed. In other words, the structure could simply be placed in the rain and it would start to biodegrade, restoring its natural materials to the ecosystem.
The technology used to create the Aguahoja I is called “Water-based Digital Fabrication,” a process capable of manufacturing biodegradable structures using a robotic gantry system and the tunable biomaterials.
As the Mediated Matter team writes: “The Aguahoja I platform is comprised of a robotic gantry for 3D printing biomaterials where shape and material composition are directly informed by physical properties (e.g., stiffness and opacity), environmental conditions (e.g., load, temperature, and relative humidity), and fabrication constraints (e.g., degrees-of-freedom, arm speed, and nozzle pressure), among others.”
Perhaps the most captivating thing about the project is the versatility of the naturally derived materials. The 3D printed structures, all made from the same base materials of chitin, cellulose, pectin and calcium carbonate, can be tuned for specific functions and for their environment. Like how chitin makes up the exoskeletons of crustaceans and the cell walls of fungi, the biocomposites are highly adaptable, and not just before printing.
As the pavilion and the artifacts of the Aguahoja project demonstrate, the materials respond to changes in humidity and heat as well as to the different seasons. Some are described as brittle and transparent, while others maintain flexibility and leather-like toughness.
“Despite their emergent diversity, these artifacts share a common quality—in life their properties are mediated by humidity; in death they dissociate in water and return to the ecosystem,” the research team adds.