The low-cost FibeRobo could be utilized in adaptive performance wear or compression garments because it is compatible with existing textile manufacturing procedures.
Instead of needing a coat for each season, picture a garment that changes shape dynamically to become more insulating to keep you warm as the temperature drops.
This concept could one day become a reality thanks to an interdisciplinary team of MIT researchers who created a programmable, actuating fiber. Without any implanted sensors or other hard components, the fiber, known as FibeRobo, self-reverses when the temperature drops and contracts in reaction to an increase.
The inexpensive fiber may be manufactured continuously by the kilometer and is entirely compatible with textile manufacturing techniques, such as industrial knitting machines, weaving looms, and embroidery. This could make it simple for designers to add sensing and actuation features to a variety of materials for a wide range of uses.
The fibers can also be combined with conductive thread, which acts as a heating element when electric current runs through it. In this way, the fibers actuate using electricity, which offers a user digital control over a textile form. For instance, a fabric could change shape based on any piece of digital information, such as readings from a heart rate sensor.
Textiles are used in everything we do. Fiber-reinforced composites are used to construct aircraft, and they are also used for performance wear and personal expression.
An example of this is the fabric used to block radiation aboard the International Space Station. According to Jack Forman, a graduate student in the MIT Media Lab Tangible Media Group who also serves as the lead author of a paper on the actuating fiber, so much of our environment is adaptive and responsive, but the one thing that needs to be the most adaptive and responsive — textiles — is completely inert.
He is joined on the paper by 11 other researchers at MIT and Northeastern University, including his advisors, Professor Neil Gershenfeld, who leads the Center for Bits and Atoms, and Hiroshi Ishii, the Jerome B. Wiesner Professor of Media Arts and Sciences and director of the Tangible Media Group. The research will be presented at the ACM Symposium on User Interface Software and Technology.
Morphing materials
The MIT researchers wanted a fiber that could actuate silently and change its shape dramatically, while being compatible with common textile manufacturing procedures. To achieve this, they used a material known as liquid crystal elastomer (LCE).
A liquid crystal is made up of a group of molecules that flow like liquids yet stack into periodic crystal arrangements when given time to settle. These crystal structures are integrated by the researchers into an elastic network called an elastomer, which resembles a rubber band.
The fiber contracts as the LCE material heats up because the crystal molecules misalign and pull the elastomer network together. According to Forman, when the heat is removed, the molecules realign and the material stretches to its initial length.
By carefully mixing chemicals to synthesize the LCE, the researchers can control the final properties of the fiber, such as its thickness or the temperature at which it actuates.
They developed a method of preparation that yields LCE fiber that is acceptable for wearable fabrics and can actuate at temperatures that are safe for human skin.
There are a lot of knobs we can turn. It was a lot of work to come up with this process from scratch, but ultimately it gives us a lot of freedom for the resulting fiber, he adds.
Fiber fabrication
To get around the difficulties with fabrication, Forman created a machine out of 3D printed and laser cut pieces and simple electronics. His first construction of the device was for the graduate-level course MAS.865, "Rapid-Prototyping of Rapid-Prototyping Machines: How to Make Something that Makes [almost] Anything," which he took after receiving instructions.
First, the viscous and thick LCE resin is heated, and it is then gradually pushed through a nozzle similar to a glue gun. After the resin is extracted, it is carefully cured with UV rays shining on both sides of the fiber as it progressively extrudes.
The material will separate and flow out of the machine if the light is too faint, but clumps may form if the light is too bright, resulting in rough strands.
After that, the fiber is coated with oil to make it slick and is once more cured under intense UV radiation to produce a robust and smooth fiber. In order to facilitate its easy insertion into textile manufacturing machinery, the material is gathered onto a top spool and coated with powder.
From chemical synthesis to finished spool, the process takes about a day and produces approximately a kilometer of ready-to-use fiber.
At the end of the day, you dont want a diva fiber. You want a fiber that, when you are working with it, falls into the ensemble of materials — one that you can work with just like any other fiber material, but then it has a lot of exciting new capabilities, Forman says.
MIT researchers demonstrated a number of uses for FibeRobo, such as an embroidered sports bra that tightens when the wearer starts working out.
Additionally, a compression jacket for Forman dog, Professor, was made using an industrial knitting machine. A Bluetooth signal from Forman smartphone would cause the jacket to activate and "hug" the dog. A dog separation anxiety during its owner absence is frequently reduced with the usage of compression jackets.
The researchers hope to modify the fiber chemical makeup in the future to make it recyclable or biodegradable. Additionally, they aim to simplify the polymer synthesis procedure so that anyone lacking experience in wet labs can complete it independently.
When included into practical textiles, LCE fibers come to life. Although she was not engaged in this work, Lining Yao, the Cooper-Siegel Associate Professor of Human Computer Interaction at Carnegie Mellon University, finds it very fascinating to see how the authors have explored unique textile designs utilizing a range of weaving and knitting patterns.
The Dr. Martin Luther King Jr. Visiting Professor Program, Toppan Printing Co., Honda Research, Chinese Scholarship Council, Shima Seiki, the William Asbjornsen Albert Memorial Fellowship, and Honda Research all provided partial funding for this study. The members of the team were Megan Hofmann and Kristen Dorsey from Northeastern University and Ozgun Kilic Afsar, Sarah Nicita, Rosalie (Hsin-Ju) Lin, Liu Yang, Akshay Kothakonda, Zachary Gordon, and Cedric Honnet from MIT.
