Showing posts with label chemistry. Show all posts
Showing posts with label chemistry. Show all posts

Sunday, 30 June 2013

Top 10 things nanotechnology has made smaller and better

I've talked about nanotechnology before. Here, I'll talk about different products and technologies that are currently using nanoparticles or nanomaterials, and that have been improved by this area of science.

10- Fuel additives


Fuel price is the most important reason why fuel efficiency needs to be improved. Fuel additives goes in place number 10, because new green energy sources are being researched at the moment using nanomaterials, which is much better for the environment in the long run and will be much cheaper. 

At the moment, it has been shown that adding cerium oxide nanoparticles to fuel reduces the amount of fuel used, it also helps decomposition of unburnt hydrocarbons and soot, and reduces the amount of pollutants emitted in the exhaust. This technology is currently used in the UK, for buses.

One disadvantage to the use of nanoparticles in this matter is the emission of particles to the environment. These particles are likely to accumulate in the environment, in particular in roadside areas, which will result in pollution.


9 –  Construction


Nanomaterials can be very interesting to the construction industry, the provide very durable, long-lived and lightweight construction materials. Very good novel insulation nano-materials are already available on the market, and they seem to improve energy efficiency. Surface coatings are also available and being used currently, these coatings promise to conserve resources, for example water, energy and cleaning agents. Because of their high prices, the reality is that nano- products are still not very widely used in the conservative construction industry, which for the time being prefers to rely on proven, conventional products.

They are mostly used in four sectors, cement-bound construction materials, noise reduction and thermal insulation or temperature regulation, surface coatings to improve the functionality of various materials, and fire protection.


8- Cosmetics – from sunscreen to anti-aging cream


One very important use of nanomaterials in cosmetics is sunscreens. Titanium dioxide and zinc dioxide nanoparticles are currently being used in sunscreens (especially in Australia) to block UVA and UVB light very efficiently, as well as to make sunscreens less oily and spread better on the skin without leaving residues.  

Another important use is to deliver active ingredients in anti-aging screens more easily. Vitamin C, for example, is an antioxidant used to fight skin damage due to age, which works best below the top layer of skin. In bulk form, vitamin C is not very stable and is difficult to penetrate the skin, and the nano form will improve this. Nano emulsions, which means mixing two unblendable liquids – like vinegar and oil, are being used as anti-aging sprays to transport beneficial compounds deep into the skin and in high concentrations. Nano gold is used in one moisturiser available in the UK, they allege that it has healing and anti-oxidant properties.


7- Wound treatment/ antibacterial activity


It is well known that silver has antibacterial properties and is used for wound healing and burn treatment. Reducing the size of materials by using nanoparticles increases the efficiency and improves their properties. So, incorporating silver nanoparticles into the wound bandages will improve their healing properties. 

Because of these antibacterial properties, silver nanoparticles are also being used in many products, like refrigerators, washing machines, air conditioning, toys, pacifiers, clothing, food storage, etc.

6- Sports

Because of their strength and lightweight, nanoparticles are being added to sporting goods. Nanomaterials are being used in tennis rackets, which contain carbon nanotubes to make them extremely strong as well as light, also in golf clubs and shoes. Some shin-pads for footballers are made with nano-structured plastics. Floyd Landis won the Tour de France on a bicycle which had a nano-based plastic frame, and now mountain bikes with these frames are available in the market. Footballs and tennis balls are being improved by using nano-clays, which are barrier materials and retain pressure.

Clothing and fabrics are also being enhanced by nanomaterials, from antibacterial socks, using silver nanoparticles, to waterproof jackets (and sails for boats) and wind resistant clothing that is breathable – for higher temperatures.


5- Sensors and electronics

One thing that nanotechnology has been making better is transparent electronics. Highly flexible and transparent electronic devices will rely on essentially invisible electronic and optoelectronic circuits.  Nanopaper has started to replace plastic substrates because is lightweight and also low-cost and versatile.This nanopaper, made from cellulose like normal paper, has a surface that is less rough and has a much higher transparency than traditional paper. Nanopaper transistors have been made, by Liangbing Hu, an Assistant Professor in the Department of Materials Science and Engineering at the University of Maryland.

Silicon nanomembranes are also being researched to make systems that match the mechanics of the epidermis, and take the full three dimensional shapes of the fingertip as well as other appendages or even internal organs, like the heart. This technology is known as fingertip electronics.


Top: Turning the tube inside out relocates the array on the inner surface of the finger-tube, shown here at the midway point of this flipping process. Bottom: Multiplexed array of electrotactile stimulators in a stretchable, mesh geometry on the inner surface of an elastomeric finger-tube. (Images: Rogers Group, University of Illinois at Urbana-Champaign)

Quantum dots and silicon are being used to make LEDS, and a wide range of products, including lamps, displays and photovoltaics.


4- Environmental clean up

Clean water is a big concern in many countries in the world, where water sources are scarce and contaminated. Nanotechnology has proven already to be an inexpensive and efficient source of water treatment.

It has been found that magnetic rust nanoparticles bind to arsenic; the rust and arsenic can then be lifted out of the water by using only a handheld magnet. Also, iron based nano-filters have been developed as a low cost alternative to carbon-based filters. Iron filters can remove large volumes or chlorine and mercury, amongst other contaminants.

3- Technology – microchips

Some of you might not remember bulky and heavy cell phones and big and slow computers, but some of us do. Nanotechnology has been the key in making machines smaller with a larger memory. Silicon-based chips have improved speed and capacity of different devices for the last five decades.  The switches are becoming smaller and smaller, achieving dimensions with widths of just a few atoms.

Home computer in the 50's
First cellphone

Cellphone evolution

 Currently, I.B.M. physicists and chemists are working with carbon nanotubes, which are single sheets of carbon rolled into tubes, to improve conductivity and reduce size even further. A paper was published in October 2012 in the journal Nature Nanotechnology, where the researchers created patterned arrays of nanotubes on a surface, they would stick nanotubes in some areas and left other areas untouched.

2- Clean energy

To avoid further contamination and reduce energy prizes it is very important to find new and clean sources of energy. Nanotechnology has been a big part of finding more efficient and smaller new energy sources. With very small nanoparticles we can harvest very large amounts of energy.

In 2013 Nano Letters published "Toward Large-Scale Energy Harvesting by a Nanoparticle-Enhanced Triboelectric Nanogenerator", the researchers found a mechanical energy-harvesting technique – a triboelectric nanogenerator – which effectively converts ambient mechanical energy into electrical energy.


Above, the schematic and (b) photograph of a fabricated triboelectric nanogenerator. (c) SEM image of gold nanoparticles coated on gold surface. (d) Process flow for fabricating the nanogenerator. (Reprinted with permission from American Chemical Society)

Solar cells are also an important source of clean energy, many researchers are investigating the development of flexible solar cells to improve efficiency and lower manufacturing costs. The biggest problem is that inorganic solar cells have an efficiency of more than 10%, while flexible polymer solar cells still show a low efficiency (6 – 7%), this needs to be improved. A review paper in ACS NANO (
"Nanoimprinted Polymer Solar Cell") talks about imprinted solar cells, which is a method that could improve the efficiency of both organic and inorganic solar cells.

Graphene has also shown great potential in the area of solar cells, which would be inexpensive, lightweight and flexible. Graphene would also improve supercapacitors, lithium-ion batteries, and catalysis for fuel cells.

1.- Medicine  - drug delivery

This has been an area in which nanotechnology has been very important since the beginning. It is clear that most of the active ingredient of drugs is lost in the process of the delivery, through pills, injection, etc., with nanotechnology there has been a constant search to improve the targeting of organs and improve efficiency.

In March 2013 Researchers at the School of Medicine of the University of Washington found that nanoparticles could carry a toxin found in bee venom and were able to destroy human immunodeficiency virus (HIV) and didn’t harm the surrounding cells. They plan to develop a vaginal gel that can be used as a preventive measure to stop the initial infection.



Nanoparticles (purple) carrying melittin (green) fuse with HIV (small circles with spiked outer ring), destroying the virus’s protective envelope. Molecular bumpers (small red ovals) prevent the nanoparticles from harming the body’s normal cells, which are much larger in size. 

Targeted drug delivery can also be achieved by using magnetic nanoparticles are coated with certain biocompatible polymers, coupled with anticancer drugs and later guided by an external magnet to the desired organ.

Monday, 4 March 2013

Rare metals

These are some gorgeous pictures I found on tumblr. These are naturally occurring crystal formations. 


Bismuth

Flourite

Azurite/ Malachite

Pietrisite


Hafnium


Friday, 1 March 2013

Molecular gastronomy - where food and lab meet


Chemistry is a big part of our lives, even if we don’t realize it. Mixing ingredients, putting them in the oven and getting a completely new thing is actually a very complex reaction. But beyond just the science of food there’s the search of many chefs to be ahead of times when it comes to cooking, and molecular gastronomy is a very controversial and different type of cooking.  

Fruit caviar 

Hervé This and Nicholas Kurti felt the need to investigate cooking in a different way. Both had scientific background but a love of food and cooking, and most important, curiosity about what happens when you cook. They are the fathers of molecular gastronomy as a research area, which is different from food science, it takes advantage of many scientific principles used there but on a smaller scale, such as the use of emulsifiers. Molecular gastronomy could be considered a branch of food science, but food science is concerned with analysing the chemical makeup of food and developing methods to process food on a large scale.  

The term has now been adopted to describe a style of cuisine. Many have incorporated unconventional ingredients to their cooking to bring different textures and flavours to their creations. Pictured above is a ‘fruit caviar’ which was first developed by Ferran Adrià, the chef of El Bulli Restaurant in Catalonia, Spain. The technique is known as spherification, which involves making liquid-filled beads that explode in the mouth. Spherification relies on a simple gelling reaction between calcium chloride and alginate, a gum like substance extracted from brown seaweed.  Chef Adrià is one of the most important names in molecular gastronomy, as well as Chef Heston Blumenthal from London’s ‘TheFat Duck’, pictured bellow.


Chef Heston Blumenthal

Using liquid nitrogen to achieve fluid-filled fare is another popular technique. When food is exposed to extremely low temperatures it will be frozen on the surface, liquid in the centre. The technique is typically used to develop semi frozen desserts. It is also common for molecular gastronomists to play with food flavours, making very strange flavour combinations, such as strawberry and coriander, pineapple and blue cheese, and cauliflower (caramelized) and cocoa. They have learned that foods sharing similar volatile molecules -- those that leave food as a vapour in a similar way -- taste good when eaten together.

Many other techniques are used in this style of cuisine, such as making foams by using hydrocolloids or carbon dioxide, thermal immersion circulator for sous-vide (low temperature cooking), food dehydration, using syringes to inject fillings, amongst others.

Even though this style of cooking is popular to date, there has been plenty of controversy around it. Some people think the additives are unhealthy and some ingredients have been banned in countries like Italy. There has also been controversy when it comes to the name, some chefs don’t want to be associated with the name “Molecular gastronomy” and some do. And also, very important representatives of this type of cuisine have distanced themselves lately from this style of cuisine; chef Ferran Adrià announced that he will close his restaurant.  If you are against or in favour of this type of cooking, one thing can be agreed, molecular gastronomy shows how science and cooking can go hand in hand to create new things. It brings the lab to our tables and can satisfy the curiosity of a lot of people. Is the movement dead? It’s too early to tell, this young style of cooking might only be evolving. 


Personally, I am very curious about it, being a chemist and all, I really want to go to a molecular gastronomy restaurant, which I haven't been able to do, plus, I would love to get my hands on some of the equipment to make my own little master pieces at home, the kits can be found on Amazon.