Last updated May 7, 2018 at 2:40 pm
Graphene is often heralded as the wonder material for the future. But researchers have come up with an altogether more mundane use for it
Imagine a hair dye that is non-toxic, non-damaging and lasts through many washes without fading. Great.
How about if it was also anti-static, reducing the risk of constantly having that wind-blown look? Even better.
And just for good measure, it could open up new opportunities for hair, such as turning it into in situ electrodes or allowing it to integrate with wearable electronic devices. Um, let’s speak to marketing.
Strange as this all sounds, it could soon be a reality thanks to the super material graphene and researchers from Northwestern University’s McCormick School of Engineering.
A team led by Professor Jiaxing Huang has used materials science to develop a new hair dye that avoids the age old dilemma that making your hair look good actually isn’t good for your hair. And it’s all about geometry.
Commercial dyes work by using chemicals such as ammonia or bleach to open the outer cuticle layer of a hair, allowing small colourant molecules to get inside and trigger a reaction to produce more colour. Not only does this process cause hair to become more fragile, some of the molecules are also quite toxic.
By contrast, graphene sheets are soft and flexible, so they wrap around each hair for an even coat. Huang’s formula also incorporates edible, non-toxic polymer binders to ensure that the graphene sticks – and lasts through at least 30 washes, which is the commercial requirement for permanent hair dye.
“It’s similar to the difference between a wet paper towel and a tennis ball,” Huang said. “The paper towel is going to wrap and stick much better. The ball-like particles are much more easily removed with shampoo.”
This geometry also contributes to why graphene is a safer alternative. While small molecules can easily be inhaled or pass through the skin barrier, graphene is too big to enter the body. “Compared to those small molecules used in current hair dyes, graphene flakes are humongous,” Huang says.
With its ultra-strong and lightweight structure, graphene – a two-dimensional network of carbon atoms – has enormous potential in high-performance electronics, high-strength materials and energy devices. However, most possible applications require graphene materials that are as structurally perfect as possible.
However, Huang’s team was able to use graphene oxide, an imperfect version of graphene that is more available and a lot cheaper. Their hair dye currently only comes in multiple shades of brown and black, but they are planning to experiment with colours.
Beyond that is the potential to leverage graphene’s other great properties, including its highly conductive nature.
“People could apply this dye to make hair conductive on the surface,” Huang said. “It could then be integrated with wearable electronics or become a conductive probe. We are only limited by our imagination.”
The paper published in Chem.