Teflon is the non-stick coatings in saucepan which was discovered in 1938 by accident. Scientists were trying to make a new refrigerant and came up with Teflon instead. The glue on post–it notes was invented by a scientist trying to develop new glue for sticky tape which didn’t stick permanently and later on the idea of sticky-backed peel of notes came up. Kevlar was invented to strengthen car tyres.
Carbon fibre: very strong and light- combined with plastic to make a composite material. It’s used to make the bodywork for formula one car, bike frames, tennis rackets and fishing rods. Thinsulate: good thermal insulation because it’s got thin fibres which trap a lot of air – used for ski clothes and outdoor clothing. Lycra: stretchy and crease-resistant- combined with other fibres and used in tights, swimwear and sportswear.
Novel Properties 2
Breathable waterproof jackets like Gore-tex allow water vapour to escape but prevent liquid from coming in. These are made by laminating a thin film of plastic called PTFE onto a layer of another fabric such as polyester or nylon. Both liquid and water vapour could pass through the fabric. The expanded PTFE film has tiny holes which allow the water vapour to pass but not the water droplets.
Kevlar is a synthetic material which is as strong as steel, light and flexible which is ideal for protective clothing. Body armour made of woven Kevlar fibres is soft and comfortable to wear. Cut-resistant gloves made for workers in glass factories are made of Kevlar. The heat resistance of Kevlar means it’s ideal for firefighter’s helmets. It’s also used in aircraft, sports gear, ropes, ships and oil rigs.
Nitinol: ’shape memory alloy’. It’s a metal, but when it’s cooled you can bend and twist it like rubber. If it’s bent you can put it in hot water and it will spring back into its original shape (glasses).
Some dyes can change colour depending on the temperature. They’re used in can drinks to indicate whether it’s cold enough. It could be used in novelty cups to change designs and t-shirts. There are also dyes that become more or less transparent depending light intensity. They’re used in sunglasses to protect your eyes. Some materials expand or contract when you put an electric current through them; they also produce electricity when squeezed. This is used in airbags sensors and skis that don’t vibrate when bumped over snow. There are liquids which turn to solid when put it into a magnetic field which is used to control vibration in car shock absorbers.
Smart Materials 2
Intelligent packaging can be used to monitor the food and test whether it’s okay to eat or has gone off. The special dyes change colour when it’s getting warmer. It can tell whether the food is warm enough for microbes to grow.
Fresh food sometimes produces moisture inside the packaging. Silica gel is a chemical that absorbs water which makes it difficult for bacteria and mould to grow. Oxygen scavengers are chemicals which react with oxygen. Intelligent packaging removes oxygen so the food won’t get oxidized to change the colour and taste and it stop microbe growing. Also food packaged with absorbers and oxygen scavengers doesn’t need as many preservative.
1-100 nanometers across are called nanoparticles. Sunscreen: nanoparticles of titanium oxide and zinc oxide are used in some sunscreens. These are good at reflecting UV radiation which reduces the need of larger particles that leave thick and white sunscreen on the skin. The nanoparticles are so small that reflect UV light but not visible. Nanoparticles of silver can stop viruses from getting into cells, ordinary silver doesn’t fight viruses.
You can make nanowires out of gold for electronics (computer chips can be really small). Scientists are working on ways to combine nanomaterials with other substances to produce nanocomposites, which improves the properties of the original substance. Nanoparticles can be added to plastics to change their properties (stiffer and stronger), which can then be used in sports cars to save weight. Carbon nanomaterial can also be added concrete to make it stronger. Nanoparticles and nanotubes can be combined to make nanomachines. This lead to a story of self-replicating nano-robots which people weren’t justified with this as media were covered with ‘grey goo’.
Beer and Wine
Ethanol can be made by fermenting. Fermentation is the process using yeast to convert sugars into alcohol. CO2 is also produced. C6H12O6 = 2C2H5OH + 2CO2.
The yeast cells contain enzymes called zymase which are naturally occurring catalysts- speeds up reactions. Fermentation happens fastest at room temperature. At a lower temperature the reaction slows down, and at a higher temperature the yeast is destroyed. If oxygen gets into the fermentation ethanoic acid is produced. When the concentration of the alcohol reaches 10 to 20% the fermentation reaction stops, because yeast gets killed off by the alcohol. Different types of alcoholic drinks are made from different sources- usually from grain, fruits or vegetables. The fermented mixture can be distilled to produce a more concentrated alcohol.
Beer and Wine 2
Ethanol affects the bodies by generally making people feel less inhibited which helps people to socialize and relax with each other. However, ethanol reduces the activity of the nervous systems. Too much alcohol leads to impaired judgment, poor balance and coordination, lack of self-control, unconsciousness and even coma. Alcohol in excess causes dehydration which can damage brain cells (brain function), damages the liver (liver disease).
Getting drunk can lead to loutish behavior and violence. People can become addicted to alcohol- this can lead to family breakdown, losing jobs and even being homeless. Getting drunk can lead to irresponsible sexual behavior which can cause a sexually transmitted infection, drink driving which causes death and injury, and economic costs too.
Mix oil + water to make an emulsion. Emulsion are made up of lots of droplets of droplets of one liquid suspended in another liquid. Oil and water naturally seperate, emulsifiers stop liquids seperating.
Hydrophilic: (head) "water loving", attracted to water molecules Hydrophobic: (Tail) Attracted to the oil molecule Mayonnaise, low-fat spread, and ice-cream are foods containg emulsifiers. Mayonnaise: Contains lecithin the emulsifier.