Many engineers have attempted to attach semiconductors – an essential part of modern electronics today – to clothing, enabling wearers to monitor their health, send an alert, play their music, or perform a variety of other “connected” tasks.
Instead of adding the semiconductors at the end of the process, however, an MIT team has found a way to incorporate light-emitting diodes (LEDs) and diode photodetectors into the clothing fibers themselves.
The achievement, according to one of the lead researchers, could lead to a new kind of “Moore’s Law” revolution, where the capabilities of fibers will grow rapidly and exponentially over time.
The traditional way of creating optical fibers requires a pre-form – a cylindrical, scaled-up model of a fiber. By heating the pre-form, the softened material is then pulled downward under tension, and the resulting fiber is collected on a spool.
The MIT researchers, led by former MIT graduate student Michael Rein and his research advisor Yoel Fink, added two ingredients to the pre-form: tiny, grain-sized light-emitting semiconductor diodes and a pair of copper wires thinner than a hair’s width.
When heated in the furnace, the polymer preform is partially liquified, forming a long functional fiber – one with the diodes lined up along its center and connected by the copper wires.
The resulting fibers were then sent to South Carolina’s Inman Mills and woven into fabrics. Next, the materials were put through the laundry ten times, to demonstrate their practicality as possible material for clothing.
Fink spoke with Tech Briefs about how his team’s research is an important first step in accelerating the functions of fibers.
Tech Briefs: What is unique about how you incorporate semiconductors into fabric, compared to other attempts to do this?
Yoel Fink, MIT professor of materials science and electrical engineering: The most important thing here is getting the semiconductors into the fiber itself. The fiber, the yarn, is where we actually are putting the devices inside. It’s not attached to the fabric after it’s made; it’s part of the fabric itself. That has not been done.
In terms of getting advanced capabilities into fabric, pretty much everything today has involved using metal conductors. A metal basically conducts charge from one place to another. Metals don’t really allow you to get a whole lot of functionality. The horizon of current approaches has been quite limited. You can’t compute with a metal. You can’t store information with a metal. Now, in the age we’re in, semiconductors have never made their way into a fiber, certainly not in the way we’re doing it.
Tech Briefs: What inspired this work?
Fink: This has been topic of research in my lab for many years: How do we get fibers to take on a whole new meaning in terms of their function or dimensionality of their function? How do we get out of just basic, mechanical properties into something which is technological, which essentially allows you to develop something like a Moore’s Law, where you could deliver reliably and predictably accelerated performance and functionality?
And that’s sort of what happened in the original Moore’s Law defined for chips; the industry was able to reliably increase the function of a chip every so often. By getting semiconductors into fibers now, we’re going to see a similar type of revolution in the years ahead.
Tech Briefs: What applications do you envision with this kind of “functional fabric?”
Fink: The beauty of the approach of getting these functions into the fiber itself is that you can harness this amazingly scalable fabric manufacturing capability that exists around the world. And now just by changing the nature of the fiber or the filament, you can use the same equipment to actually produce fabric now that is capable of doing things that no fabric could ever do before.
In the paper, we show how you could communicate between two fabrics. We also show how a fabric can pick optical information from the skin, measuring heartbeat. We could also probably do blood oxygenation and measurements of this nature.
Being able to basically accelerate the functions of fibers, being able to emit light, being able to receive light, being able to store energy, being able to change color, being able to create display, being able to monitor your health, and so on – these are all things we’re working on currently and in the process of scaling.
Yoel Fink is also CEO of Advanced Functional Fabrics of America (AFFOA).
What do you think? Will we see a new kind of “Moore’s Law” with functional fabrics? Share your questions and comments below.