Yury Gogotsi and his colleagues have just developed highly conductive and scalable Ti3C2Tx-coated fabrics capable of efficient electromagnetic interference (EMI) shield. Pretty exciting, no doubt. But exactly how efficient are the high-tech products? Is their effect long-lasting enough to prevent them from being dumped like fast fashion clothes? Are they just another expensive wearable-tech fad? Or are they promising materials with considerable potential?
First of all: why do we need radiation-proof fabrics and what is Ti3C2Tx?
We (and some devices) need to protect ourselves against the electromagnetic radiation from the increasing number of wireless devices surrounding us. Due to their flexibility, minimal weight and adaptability, EMI shielding fabrics are an excellent choice.
Ti3C2Tx belongs to the MXene family. MXenes have the general formula of Mn+1XnTx, where M represents an early transition metal, X being C and/or N, Tx stands for surface functional groups and n is number 1-4. So, what does this unusual combination bring and what are its advantages over the current metal-based shielding? Metal-based shielding devices cannot be processed easily and their rigidity makes them unsuitable for small textile-based devices.On the other hand, Ti3C2Tx has a hydrophilic surface that offers superior solution processability. Moreover, compared to metal-based shielding, Ti3C2Tx can be dispersed in water without using additives and no pre-/post-processing steps are required for high electrical conductivity. Additionally, with its good metallic conductivity and mechanical properties, and crucially, non-toxicity, Ti3C2Tx is a superb EMI shielding candidate.
Nevertheless, “We have known for some time that MXene has the ability to block electromagnetic interference better than other materials, but this discovery shows that it can effectively adhere to fabrics and maintain its unique shielding capabilities.” said Yury Gogotsi, the research group leader. Thus, Ti3C2Tx -coated fabrics provide an ideal solution. Also, “…they can be sustainably produced by coating from aqueous solution without extra processing or chemical additives.” remarked Simge Uzun, a doctoral student in Gogotsi’s research group. Definitely good news for mother Earth.
Sounds charming. How do we make them and why use this method?
Dip-coating, a scalable yearn/fabric dyeing friendly approach was adopted for this product. Cotton and linen are simply dipped repeatedly into a solution of Ti3C2Tx MXene in water and air-dried until the correct amount of Ti3C2Tx has been deposited onto the fabric to give the desired electrical conductivity. The Ti3C2Tx flakes can stick to the hydrophilic cotton and linen fibres due to the fact that the flakes are negatively charged and are mono- or few-layered. Then, shaking and stirring is needed to further enrich the fabrics with Ti3C2Tx.
Seems quite simple. How efficient is this approach and what is the EMI shielding efficacy?
The straightforward method has surprising efficiency: only four dip-coating cycles give the lightly Ti3C2Tx-coated fabrics double the EMI shielding effectiveness (SE), the minimum requirement for SE. The EMI SE values were compared to that of metal-based conductive fabrics. At similar active material loadings, MXene-coated cotton and linen fabrics outperformed all measured metal-based fabrics significantly.
We need to make the best use of expensive stuff. How durable is the EMI SE of Ti3C2Tx -coated fabrics?
Fortunately, the wearable tech is quite long-lasting, meaning it will not be dumped like fast-fashion products. After storage under ambient conditions for two years, the average EMI SE performance of Ti3C2Tx-coated cotton and linen fabrics only decreased by around 8 to 13% . The authors proposed that a thin oxidised MXene layer on the fabric surface caused the SE decrease. The total EMI reduction mainly resulted from lowered absorbance of the electromagnetic radiation – rather than its reflection.
The thing we care most about: How can this amazing novel creation be adapted for different needs?
Not only can the Ti3C2Tx-coated fabrics block electromagnetic waves from communication devices through wrapping them, they can also be made into clothes that may protect citizens and diplomats from critical information security-breach through bank-card-scanning and tracking devices – in a Q-from-James-Bond style move. However, it may also be harder to locate your lost mobile phone in a Ti3C2Tx-coated sheath using GPS.
Written by Joyce Yixuan Wang and edited by Ishbel Dyke