What’s the Difference between an E-Textile, Smart Fabric, Functional Fabrics and Smart Textiles?
The e-textiles industry has a lot of jargon floating around to define the space. Some of it can get rather confusing, and currently, there only exists one official standard to clean up how language around e-textiles is used. With a lack of standards, it’s hard to keep track of which word means what—especially with how language changes over time. For example, Wikipedia used to explain e-textiles as a synonym with Fibretronics—a word that absolutely no one uses to describe the industry.
Preamble aside, the aim of this article is to define a few terms used to describe this industry in order to inform designers and engineers who may want to use e-textiles as an enabling technology for their developments. We’ll dig into what an e-textile is and isn’t and how words like smart fabric, functional fabrics, and wearable fabric all relate to electronic textiles. As a sagan of salt, this is LOOMIA’s opinion on language, so make sure to check out the embedded links for a well-rounded point of view.
Before we dig into words that live in the same world as e-textiles, it can be helpful to start with discussing what an e-textile itself is. The word “e-textile” stands for electronic textile or electronically integrated textile (as used by the American Association of Textile Chemists and Colorists). There are a few different definitions out there, but they all touch on this idea of electronics and textiles uniting. Often, people get the notion that e-textiles are more textiles than electronics, but often, they are heavily driven by electrical engineers, especially when it comes to printed circuitry. Tangent aside, below are two definitions to show the variety in defining this space.
“Electronic textiles (e-textiles) are textiles that are, or are part of, electronic components that create systems capable of sensing, heating, lighting or transmitting data.” Science Direct
“An electronic textile (e-textile) is a type of fabric that contains electronic elements. In general, the development of electronic textiles supports the idea of wearable computing, or electronic devices worked into garment designs. However, there are other applications of electronic textiles, such as interior design technologies, that also rely on integrating electronic components into fabrics or fibers. An electronic textile may also be known as a smart textile.” Techopedia
An electronic textile (e-textile) is a circuit that is either constructed into a textile or created with the intention of being integrated into a textile.
Those who are less familiar with this industry may be wondering why someone would want to integrate textiles and electronics to begin with. To provide some context, e-textiles can be used for medical devices (think of a heart rate monitoring shirt), in automotive interiors (think car seat heaters), and outdoor gear (think light-up tents or running apparel). The idea here is that e-textile circuits can be designed to do many things—just like traditional circuits can. In some cases, e-textiles can be lighter than traditional wiring, making them useful for aerospace and electric vehicle performance.
There are two main ways to make an e-textile: embedded and laminated.
Embedded e-textiles mean that the circuit is knit or woven into the textile to become part of the fiber of the cloth. This can also include directly printing a conductive pathway onto a textile to give it conductive properties. This branch tends to be more of a derivative of textiles than electronics.
Laminated e-textiles mean that you are printing or manufacturing circuitry on a non-textile substrate and then adding it to a textile using sewing or bonding. This branch tends to be more of a derivative of electronics than textiles.
Now that we have a written definition and some idea of what it means, let’s try a visual comparison to help explain what an e-textile is and is not.
Is this conductive thread from Adafruit an e-textile?
We would say no, this is not an e-textile. It is a conductive material, but similar to how a block of copper is not a circuit, a conductive thread is not an e-textile. The American Society for Testing and Materials (ASTM) would define this as a metallic fiber.
In general, e-textiles are systems. They are a combination of conductive material and non-conductive material patterned together to make a functioning circuit. Sometimes this system includes additional components (like LEDs) and sometimes it does not.
What about this touch sensitive fabric from Drexel University?
Yes, we would call this an e-textile. This is an embedded e-textile, made with a knitting machine. The conductive traces are part of the fabric itself, and the entire unit can be part of a complete circuit.
How about this flexible playmat that we make?
Naturally, we would say yes! This circuit is laminated to a piece of satin fabric to perform a function. It has a connector and lights, so it is an entire system that consists of conductive and resistive parts.
Now that we know what an e-textile is and isn’t, let’s explore some frequently used words.
WORDS THAT WE WILL EXPLORE:
E-Textiles (Electronic Textiles or Electronically Integrated Textiles)
Smart Fabric and Smart Textiles
E-textiles is a more technical term that seems to be used by both the maker and engineering communities. One can find this term used to name papers such as “E-Textile Technology” (E. Ghandi et al.) and to define projects on the popular maker website, Instructables. It is also used by standards groups, such as IPC (the Association Connecting Electronics Industries), and the American Association of Textile Chemists and Colorists (AATCC).
FUNCTIONAL FABRICS and TECHNICAL TEXTILES
AFFOA (Advanced Functional Fabrics of America) prefers the term functional fabrics, which covers a wide range of active and passive materials. Yoel Fink, the CEO of AFFOA, has a background in fiber optics and focuses on making fiber optic threads that have the function to be woven into textiles. IFAI (The Industrial Fabrics Association) prefers to use the term smart fabrics. Both terms, technical textiles and functional fabrics, include passive materials in their definitions.
Soft circuits is a term that is mostly used by makers in the industry. This term mostly represents conductive thread or handmade circuits that are developed onto or into a textile substrate. Famed makers in this space include Hannah Perner Wilson of Kobakant and Lara Grant, as well as Maggie Orth. Ben Cooper of FLEX is expanding the definition of this term with the term soft systems. Soft is also used by Stretchsense to define their soft sensors.
Others in the space are technical designers who focus less on the enabling technology and more on the larger category of wearable technology. Yuchen Zhang and Hellyn Teng at Wearable Media Group are great examples of this category.
Many companies selling products (e.g. WearableX, Bonbouton, and Athos) that include these technologies never refer to the textile circuitry within. Once an e-textile has entered a product, it will often be called wearable technology or smart fabric.
SMART FABRICS / TEXTILES
So, why isn’t a smart fabric or textile always an e-textile? On July 29, 2019, ASTM’s D.13 Group released a standard set of definitions called “Standard Terminology For Smart Textiles” that defined this word as something much broader. In their standard, they do not include the word e-Textile, but they do define the following:
Their definition of smart textile does not require an electrical function, but a response to stimuli, making thermochromic and non-electronic materials potentially a smart textile. Source
PRINTED ELECTRONICS/ ULTRAFLEXIBLE CIRCUITS
The printed electronics industry has started printing conductive traces onto a thin, plastic film called TPU. Printing on this film can make a very drapable and flexible circuit—an ultraflexible circuit—that can bond well to textiles. These circuits can be engineered for textile integration, making them e-textiles, or they can be engineered for other use.
Sometimes people have the intuition to combine the term wearable technology and fabric. In the end, they come up with terms like wearable fabric or wearable clothing. These terms make an incorrect use of the word “wearable” which is a useful adjective next to a non-wearable thing like technology. Next to a normally wearable thing like clothing, it’s just redundant.
In conclusion, using the terms “e-textile”, “e-textile system”, or “soft circuit” will generally result in something that is an electronic system integrated into or made with the intent of integrating into a textile. Much broader words like wearable technology, functional fabrics, and technical textiles can also mean this, but may also mean something that is chemical or passive.
However you describe e-textiles, you'll probably get your message across. Just don't say wearable fashion!
LOOMIA LANGUAGE GUIDE
An electronic textile (e-textile) is a circuit that is either constructed into a textile or created with the intention of integrating into a textile.