Tag Archives: clothes

Why are jeans blue? New Infographic: Chemistry of LEVI’S®

Chemistry of LEVI'S® chemistry infographic jameskennedymonash.wordpress.com

Today’s graphic explores the chemistry of Levi’s® famous blue jeans. It’ll show you why they’re blue, and how the dye is made; why the blue colour survives so well in the wash; and what’s special about the denim cotton weave that makes your Levi’s® jeans so strong.

Indican is a colourless, water-soluble compound extracted from leaves of the Indigofera species. Indican is a dextrose molecule conjugated to an indoxyl group by a glycosidic ether (C–O–C) bond.

The indican is hydrolysed at high pH, which separates the dextrose from the indoxyl group. The resulting indoxyl compound is whisked to aerate it, which causes the indoxyl molecules to oxidise and dimerise into indigotin, which is the famous blue dye used in Levi’s® jeans.

However, the indigotin blue dye isn’t soluble in water, and must be changed chemically before the jeans are dyed. Indigotin is subjected to high pH again, which reduces the indigotin, forming leuco-indigotin (also known as indigo white dye), which is, despite the name, pale yellow in colour.

Jeans are steeped in this water-soluble “indigo white dye”, which is still pale yellow at this stage! However, as soon as the jeans are removed from the vat of dye, the leuco-indigotin oxidises back into indigotin, which is blue in colour. The oxidised form (indigo blue) is insoluble in water, which helps the colour stick to the jeans despite being washed hundreds of times.

Denim is a traditional way of weaving cotton into a thick, sturdy material. Cotton is predominantly cellulose, a strong polymer of beta-D-glucose monomer units. Several thousand glucose monomers are present in each polymer chain. Polar hydroxyl groups form hydrogen bonds with hydroxyl groups on adjacent chains to form strong microfibrils, which the cotton plant then meshes into a strong poly- saccharide matrix. This matrix, and the denim weave, give high strength and durability to your Levi’s® jeans. ●

My T-Shirt Store is Now Open!

Love Science? Show off your love of “organic” chemistry with an Ingredients T-Shirt from James Kennedy Clothing. All our T-shirts are made in Australia. Priced from just $15.95 each.

Visit our store here: http://jameskennedymonash.secure-decoration.com/shop

James Kennedy Clothing T-Shirt Store
Click the image to visit the official “All-Natural Ingredients” Store

Just 10 days after it was created, the Ingredients of an All-Natural Banana was already the third most Reddited post of all time on Reddit Chemistry.

They were downloaded 7,000 times last week from this website alone.

I didn’t intend to make any more of these images. Three was enough. But I decided to take this Ingredients theme a bit further after I saw how widely they’d been circulated on Tumblr, Twitter, Facebook, and various other social media sites—many of which are in foreign languages—and none of which, I use.

So welcome to the Store. There’ll be more products coming soon if people like what’s already up there. I welcome your feedback as always. James 🙂