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

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

Why is Coffee so Irresistable? The Chemistry of STARBUCKS®

Many people are openly addicted to coffee. In northern Europe, home of the world’s greatest coffee drinkers, annual coffee bean consumption hovers around 9 kg per capita, which equates to 400 mg of caffeine per person per day (this is a highly addictive, highly stimulating dose). In North America, coffee bean consumption is much lower at 4.2 kg per capita per year, which equates to 185 mg of caffeine per person per day. However, this is still a highly addictive dose.

Chemistry of STARBUCKS jameskennedymonash
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Caffeine (around 225 mg in the beverage shown above) causes short, sharp increases in your blood pressure. It makes you feel alert, but jittery in large doses. Caffeine stimulates nerves by counteracting adenosine, which is a nerve activity suppressant. The brain develops a tolerance to caffeine intake after a few weeks, which can cause some people to take increasingly large doses—sometimes exceeding the ~300 mg per day limit recommended by many doctors. That said, smaller doses are believed to provide some protection against Parkinson’s Disease in the long term.

Milk, a butterfat emulsion, gives the coffee its light colour and pleasant mouthfeel. Vanilla syrup adds an interesting flavour and aroma, and consists of glucose syrup and vanillin, an artificial flavour compound modelled on the main aroma compound in real vanilla beans.

The most amazing aspect of the product shown is the polypropylene cup. Starbucks® sells these reusable cups for just $1 in its United States stores, which is part of an attempt to serve 5% of all its beverages in reusable containers by 2015. In addition to giving you a 10-cent discount for bringing your own cup, and selling these reusable cups ridiculously cheaply, Starbucks® makes these cups from a fully recyclable plastic that’s completely inert at boiling-hot temperatures (100°C). This ensures that absolutely nothing from the cup leeches into your piping hot drink before you drink it. ●

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 🙂

Very Inspiring Blogger Award

Thank you, Thea Christie, for awarding me the Very Inspiring Blogger Award.

Very Inspiring Blogger Award

The rules of the award are as follows:
  1. Link back to the blogger who nominated you. Done.
  2. Post the award image to your page. Done.
  3. Nominate other blogs for the award and inform them about it.

Here’s a selection of WordPress blogs that deserve my nomination: