Synthetic polymers like nylon were invented during World War II (America and its allies were at war with the countries that produced silk and rubber)
Plastics are synthetic polymers, such as - polyethylene (used in cling film), - polystyrene (hot drink take-away cups) - Teflon (used for non-stick cookware)
Synthetic fibres and plastics are composed of monomers which are extracted from crude oil and modified by chemists.
Types Of Fibres Adapted from Elvins et al. (1995) ‘Materials Chemistry in Everyday Life’, Heinemann Chemistry in Context, Chemistry One Second Ed. Southbank Books, Port Melbourne. FIBRES Natural Synthetic Plant based (cellulose): Cotton Linen Hemp Jute Mineral Asbestos (rarely used) Animal Based (protein) Wool Silk Cashmere Angora Metal Wires Filaments Lurex Synthetic Nylon Polyester Acrylics Elastomers Polypropylene Regenerated Viscose Rayon Casein Seaweed based Inorganic Glass Carbon Quartz Ceramics
Intermolecular bonding = the way molecules “stick” together
Molecules of water (H 2 0) can form intermolecular bonds with each other, depending on the ambient temperature.
Polymers can be stretchable, bouncy, sticky or hard, depending on how their atoms and molecules stick together. Intermolecular bonds can be formed between polymer chains that affect the properties of the final product
An attractive force operates between polymer chains - if there are only weak interactions between polymers chains, then these long polymer molecules can slide over each other; such polymers are soft and can be stretchy, eg cling wrap - if there are rigid bonds between the polymer molecules, a harder, more brittle structure is formed, eg solid plastic. These can be created by using monomer molecules to join together long polymer chains.
Ethene gas molecules can be joined together to make a polymer called polyethylene - if no links are formed between the chains then the polymer can be used to make cling wrap - if chains of polyethylene are linked together with extra ethene molecules via intermolecular bonds then hard plastic road barriers can be made.
Experiment 1 and 2
Perform one or both of the Making and Investigating Plastics experiments
Experiment 1 - Making Casein
Experiment 2 - Making Nylon
to further explore the characteristics of polymers.
Chemical Control Of Synthetic Textile Properties
The properties of a synthetic textile can be controlled chemically by modifying the polymers involved in their synthesis
Altering reaction conditions can affect how strongly the polymer molecules are attracted to one another, and in turn, how strong or flexible the fibre and textile will be
Atoms or small molecules can be added to the monomers or the polymers to give them unique properties.
Nanotubes In Unique Textiles Image: Courtesy Ray Baughman
Carbon nanotubes can be spun into fabric to form nanocomposite fibres - this is currently an area of research at CSIRO, Australia - very strong and yet lightweight fabrics are possible
Spun carbon nanotubes can be 3x stronger than spider silk - made by bonding carbon nanotubes with the polymer PVA.
Half the threads in this textile are black carbon nanotube threads
There are many fabric products on the market which currently use nanotechnology in their manufacture eg DuPont, NanoTex
Stain free fabric employs custom-designed nano-sized whisker-like molecules attached to fabrics which fend off spills and resists stains without changing the material's characteristic look and feel.
Perform the Observing Fabric Properties Experiment to see the unique characteristics of nano fabrics.
Nano-Textiles: Military Applications Nano-fabrics offer the following possibilities to the military: Image: soldiersmediacenter@flickr - Instant camouflage to environment; - manipulate light to make soldiers invisible; - Change a shirt-sleeve into a splint or cast; - Possess built-in sensors of soldiers’ physical condition and location; - Weave radio communications directly into the uniform's fabric; - Automatically administer medicines & transmit vital signs to distant medics; - Provide impact protection materials and systems; - Provide chemical and biological protection.
Nano-textiles: Liquid Armour Image: paulk@flickr
Impact resistant: bullet proof, will also resist pointed objects such as needles, icepicks, swords
Made from a ballistic fabric (eg Kevlar) filled with a shear thickening fluid - this is a water like liquid (polyethylene glycol) that contains silica nanoparticles
Under normal conditions, the armour is like water but it stiffens on impact
Materials such as this are perfect for combat - imagine Superman with a suit which allows flexibility for crime fighting while at the same time enabling him to protect vulnerable areas (so that’s why he wears his undies on the outside!)
Since the material is also very lightweight it will not result in extra energy expenditure during movement (eg Superman flying).
Unique Textiles Many companies are currently using nanotechnology to create unique textiles.
Mushon is a nanotechnology-enabled deodorant - can be coated onto polymer fabrics such as nylon and polyester - has odour elimination and antibacterial properties
Mushon was successfully tested by astronaut Tako Doi in his mission to the space station in 2008.
What If? What if your clothes could always smell like your favourite fragrance? Image: derek7272@flickr “ Research scientists at Bayer Chemicals have developed a new technology for ‘packaging’ fragrances in an ultra-thin nanofilm to form microcapsules. Leather and textiles sprayed with these microcapsules then release a soothing or exotic fragrance…..when subjected to pressure”.
What if polymers could sense and respond to your environment? Image: Courtesy Gordon Wallace, Uni of Wollongong.
Nanotechnology has been used to create conductive polymers - these polymers contain carbon nanotubes or other components which respond to the environment - examples include : ink jet-printed functional polymers which can detect volatile compounds; polypyrole polymer which expands and contracts (could be used for artificial muscles).
Carbon nanotubes may one day be used to repair the spinal cords of people who are paralysed.
Scientists at the Bionic Ear institute in collaboration with University of Wollongong are developing polymers in gel or solid form to deliver agents that will encourage spinal cord repair
Describing the technology, inventor of the Bionic Ear Professor Graeme Clark said “The polymers will create a scaffold for the neurons to grow along, while maintaining their viability and suppressing neural scar formation that could block nerve pathways”.
Intelligent Design In Polymers
It is possible to create new types of polymers. They can be incorporated into clothes so that they light up or carry electric signals
Phillips have designed a range of sensors that can be fitted to underwear. In the event of a health crisis, these can alert medical authorities - so that’s another reason for Superman to wear his undies on the outside! He can signal to approaching aircraft and call for help if necessary.
Superman Image: loresjoberg@flickr So we have a few ideas about why Superman wears his undies on the outside…
Superman Image: loresjoberg@flickr What other special properties must Superman’s suit have?
Superman’s Nanosuit Activity
Divide into groups and consider: - why does Superman need such a resplendent item of clothing? - how does Superman use his suit to perform his duties as a superhero? - what special properties of Superman’s suit allow him to perform his duties?
Superman’s Nanosuit Activity
Superman has lost his suit. Apparently he left it in the very last telephone box in Metropolis and while he was off saving the world, the phone company removed the box and destroyed it
Being a nanotechnologist working for a textile factory, you have been offered the top secret contract to make Superman a gorgeous new version of his iconic outfit
Using your knowledge of nano-scaled materials, explain what materials the suit will be made from, why you have chosen a particular material and how it exhibits the properties described.
Superman’s Nanosuit Activity
SUPER PROPERTIES :- what special properties will the suit need to have? For example: when Superman stops bullets his suit is not damaged; what properties of the suit will allow him to absorb energy from the sun?
FABRIC PROPERTIES :- Consider stretch, durability, colours. Superman needs to be able to move easily when he is chasing villains. Also it is very cold up in the stratosphere and he must resist heat on re-entry to the atmosphere
CLEANING AND STORAGE : - How will the suit maintain its shiny lustre? Will Superman need to do the ironing before a rescue?
SAFETY :- Materials must be non-hazardous to Superman, and it is important that aircraft and spacecraft can see him clearly
AERODYNAMICS :- Superman needs to maintain a streamlined shape. His cape must provide him with adequate lift. He needs to alter the directions of the forces acting on him if he wants to change direction quickly. The cape must work efficiently on earth and in the stratosphere.
Consider the following points:
Polymers are evident all around us
Polymer characteristics depend on the type of monomer and the intermolecular bonds operating
Textiles with unique characteristics can be generated by incorporating nanotechnology into existing polymers.
Explain what is meant by the term “textile”
How has nanotechnology improved textiles?
What are polymers?
List 5 things that are made from polymers.
What potential applications are there when polymer chemistry is combined with carbon nanotubes?
Describe in detail one application of nanotechnology in textiles
List three fabrics/brand names that make clothes using nanotechnology.