Nanoscience and smart materials

• What is the diameter range of a nano-scale particle?

  1 – 100 nm
• What is the equivalent of 1 nm in meters?

  1 × 10$^{-9}$ m
• How do the properties of nano-scale particles differ from their normal form?

  Nano-scale particles have very different properties from the normal form of the substances.
• What is one application of nano-scale silver particles?

  They are used in wound dressings to prevent infection.
• How is nano-silver used in socks and fridges?

  To kill the bacteria that cause bad smells.
• In what way is nano-silver used in deodorants?

  To kill bacteria that cause bad smells.
• How does nano-silver disinfect water supplies on the International Space Station?

  By killing bacteria and viruses.
• What is the main use of bulk silver?

  In jewelry.
• What is the role of titanium dioxide nanoparticles in sunscreen?

  To block harmful ultraviolet light.
• Why are titanium dioxide nanoparticles used in sunscreen invisible?

  Because they are so small that they cannot be seen.
• How do titanium dioxide nanoparticles contribute to self-cleaning windows?

  They can break down the dirt on the surface of the windows.
• What are smart materials and give examples?

  • Smart materials respond to environmental changes.
  • Examples include:
  • Thermochromic pigments
  • Shape memory polymer
  • Shape memory alloy
  • Hydrogels
• What are the potential concerns regarding nano-scale particles?

  • Long-term effects on health are unclear.
  • Environmental impact is still being studied.
• What is the status of the use of nano-scale particles?

  The use of nano-scale particles is relatively new.
• Why is it unclear what the long-term effects of nano-scale particles might be?

  Because their long-term effects on health and the environment are still unknown.
• How can nano-scale particles affect the human body?

  They can easily pass through our skin and into our bloodstream.
• What is a potential risk of nano-scale particles entering cells?

  The effect that these nanoparticles could have is not known.
• How can nano-scale particles impact the environment?

  They can easily enter the environment and could cause harm to plants and animals.
• What is an example of nano-scale particles used in clothing?

  Nano-scale silver is used to kill bacteria that cause unpleasant odours.
• What happens to nano-silver during washing?

  It can enter the water and subsequently the environment.
• What could be a long-term consequence of using nano-scale silver in clothing?

  It could cause damage to bacteria within the ecosystem over time.
• Is there evidence of negative effects from short-term use of nanoparticles?

  No, there is no evidence that short-term use has negative effects.
• What is the primary focus of the study material?

  Smart materials and nano-scale particles
• What is a key concern regarding nano-scale particles?

  Their long-term effects on health and the environment are unclear
• What are smart materials?

  • Materials that change properties reversibly
  • Changes depend on environmental conditions
• What is an example of a thermochromic pigment?

  Colour-changing novelty mugs
• How do thermochromic pigments function?

  They change colour at specific temperatures
• What is a common application of photochromic pigments?

  Photochromic lenses for glasses
• What happens to photochromic lenses in sunlight?

  They darken when exposed to ultraviolet light
• What is a shape memory polymer?

  A polymer that returns to its original shape when heated
• In what applications can shape memory polymers be used?

  Sporting equipment and medical stitches
• What is a shape memory alloy?

  A mixture of metals that returns to its original shape when heated
• How do shape memory alloys assist in medical applications?

  They apply greater tension for faster healing
• What is an example of a shape memory alloy?

  Nitinol, a mixture of nickel and titanium
• What are hydrogels capable of absorbing?

  Up to 1,000 times their own volume in water
• What triggers hydrogels to release absorbed water?

  Changes in temperature or pH
• What are some applications of hydrogels?

  • Artificial muscles
  • Hair gel
  • Nappies
  • 'Magic' expanding snow
  • Granules for soil water retention
• This is an example of thermochromic pigment.

  
• This is an example of photochromic pigment.

  
• This is an example of shape memory polymer.