Creating Colour Changing Clothes with Nanotechnology
Cheap and fashionable clothes are what everyone wants. Being able to see a fashion garment and find that piece of clothing in store is perfect for keeping with the trends. These mass produced clothes help consumers get the fashion trends quickly and at an affordable price, but it causes huge amounts of environmental damage and uses up great amounts of resources.
Fast fashion companies look at the clothing trends and mass produce them to satisfy the consumers wants. These clothes are not made to last and are created with cheap materials. Companies are able to mass produce cheap clothes by housing their factories in developing countries, where they can pollute the surrounding area with textile waste and exploit workers. It also takes huge amounts of resources to create these garments. For example, to create one cotton shirt it takes 700 gallons of water, and to create one pair of jeans it takes 2000 gallons of water. Imagine how much water it would take to produce all the garments in an clothing store! The clothes that are not sold to consumers end up in landfills or are burned in an incinerator. These landfills pollute ground water and the surrounding environment, and incinerators pollute the air with harmful toxins.
Fast fashion creates many problems for ecosystems, surrounding communities, and it contributes to climate change. The fashion industry emitted 1.2 billion tonnes of carbon dioxide per year, which is 10% of global Co2 emissions. Companies and consumers need to change their policies and mindsets to reduce the amount of environmental damage. Consumers often purchase clothes which they never end up wearing, or wear a piece of clothing once or twice until it gets thrown out.
To cut down on over consumption, I have been researching into creating a piece of clothing which can change colours using Nanotechnology. A nanomaterial called Quantum dots is able to change colours using UV light.
Quantum Dots
Quantum dots are nanocrystals which range in size between 1–10 nanometers. Depending on their size, they can change colour and have special electrical features.
When an Ultra Violet (UV) light source is shone onto a quantum dot, the electrons within the particle get energized and glow a specific colour depending on the quantum dot’s size. While being energized, the electrons create a conduction band around the particle in which electrons are free to move and conduct electricity. Then, the electrons drop back into the lower valence band around the quantum dot and emit light. The color of the light emitted depends on the difference of size between the conduction band and the valence band, known as the band gap. The size of the band gap depends on the overall mass of the quantum dot. As the quantum dot gets smaller, the size of the conduction and valence bands decrease which makes the band gap increase. Decreasing the size of the quantum dot shifts the wavelength to higher energy which emits a blue colour, while increasing the size of the quantum dot has lower energy characteristics, which glows a red colour. Other sizes emit colours such as green, yellow, orange and purple.
Quantum Dot Synthesis
Colloidal synthesis of quantum dots is one of the most cost-effective methods of creating the nanomaterial. Colloidal synthesis is a solution-based chemical process which includes heating different substances and activating it with another substance to form nanocrystal growth. The size of the quantum dots produced through colloidal synthesis is controlled by regulating the concentration of the single molecules which react to other molecules to form the crystals in the solution. Precise temperatures need to be regulated throughout to have the correct nanocrystal growth.
If you want to see how they can be made with basic household materials, check out this article of mine where I created quantum dots:
Quantum Dot Dyes
Applying these quantum dots on a shirt would make the shirt be able to change colours. For example, if the shirt was originally black and had a transparent layer of blue quantum dots on them, the shirt would turn blue when illuminated by a UV light.
To apply them on the shirt, the quantum dots can be turned into a fluorescence paint. There are many different types of quantum dot paints and dyes. For example, one quantum dot paint was made with quantum dots and with nontoxic polyethylene glycol (PEG). The quantum dot solution is already liquid, and by adding the PEG it can turn into a usable paint.
Lasting Excitation
Quantum dots can glow a specific colour only when illuminated by a UV light, so when there is no UV light there is no colour. This is an issue because it is difficult to carry around a UV light with you while wearing this piece of clothing. It is possible to make the quantum dots glow without the UV light by encasing them in cyanuric acid. Covering the quantum dots with this substance allows the solution to form donor-acceptor blends which have highly stable excitation states and can slowly release the energy from the dots instead of immediately releasing them when the UV light is not being shone on them. The light is released from the dots over a span of a couple hours. This is great for having long lasting excitation from the quantum dots, though there are some practicality issues.
Issues
A few issues with this design include putting the long lasting quantum dots on the shirt, making it last more than a few hours, issues when caring for the shirt, and working outside. The long lasting excitation quantum dots need to be submerged in the cyanuric acid, and they wouldn’t be able to be applied to a shirt in that state. Currently, the excitation can only last a couple hours, which isn't enough to last throughout the day. There could also be issues when washing and ironing the shirt. The quantum dots could wash off if not applied correctly. Also, if the user wanted the shirt to be the colour of the fabric and not the quantum dots, the sun’s UV light could change the colour while being outside which was not desired by the user.
Next Steps
I chose to work on a fashion idea because I love to crochet and make my own clothes and I’ve been recently researching into Nanotechnology, so I wanted to pair two of my interests together. I am still working on this project and trying to create a usable t-shirt which can last throughout the day and can work outside in the sun. This idea may not be the best way to solve the issue of consumption, so I am also looking into other ideas which pair nanotechnology and fashion to help reduce over consumption.
The issue of fast fashion is causing huge negative impacts to our environment. Consumption is something which consumers can control, so we need to slow down our rate of consumption by buying less clothes and creating alternatives to fast fashion.
If you enjoyed reading this article, check out my medium page and LinkedIn: https://www.linkedin.com/in/lily-chandran-262b2a1a3
