Doc Brown's Chemistry Revision Notes  NANOCHEMISTRY - Nanoscience - Nanotechnology - Nanostructures

Part 3. Uses of nanoparticles of titanium(IV) oxide, fat and silver

Alphabetical keyword index for the nanoscience pages : Index of nanoscience pages : boron nitride * Buckminsterfullerenes-bucky balls * carbon nanotubes * fat nanoparticles * fluorographene * fullerenes * graphene * health and safety issues * liposomes * nanochemistry * nanomaterials * nanoparticles * nanoscale * nanoscience * nanosize-nanosized-particles * nanostructures * nanotechnology * nanotubes * problems in nanomaterial use * silver nanoparticles * safety issues * sunscreens-sunblockers * titanium dioxide

Part 3. Uses of nanoparticles of titanium(IV) oxide (titanium dioxide, TiO₂)

• How does titanium dioxide protect us from uv light? What does titanium dioxide do in sun creams?

• In the cosmetics industry the use of nanosized particles in creams etc is increasing, because of the small particle size, they can be more easily absorbed through the skin, as in moisturisers.

• Titanium dioxide, TiO₂, is a white powder and a good reflector of visible light and most commonly encountered as a brilliant white pigment in paint.

• However, it also used in the cosmetic and skincare products industry as a pigment, thickener, moisturiser and used in sunscreens as a uv absorber.

  • Ultraviolet light from the sun impacting on the skin can cause cell damage, e.g. DNA damage, which can lead to skin cancer.

• Titanium dioxide is a good uv light absorber and is effective as many organic molecules used as uv absorbers in many commercial sun creams.

  • Some of these 'sun blocker' molecules can cause skin irritations on sensitive skin

• Nanoparticles of titanium dioxide are incorporated into 'sun blockers', though the particles have to be specially coated (*) to avoid skin irritation problems from using such titanium dioxide based sunscreens.

  • (*) Apparently the interaction of uv light and titanium dioxide in the presence of other molecules can produce highly reactive and harmful free radicals.

• As well as being a good uv absorber (90% absorbed, 10% scattered), nanosized titanium dioxide particles have 2nd another advantage.

  • The TiO₂ particles are smaller than the wavelength of light and are therefore too small to see, and when used in sunscreen creams they are transparent to light rather than opaque, so the skin looks a more natural colour nanochemistry meets human aesthetics!

    • The wavelength of visible light ranges from 300 to 700 nm.

    • The nanoparticles of TiO₂ typically used vary from 20 to 170 nm in size.

  • A good example of where particle size matter, and the tiny size of titanium dioxide particles gives it this commercial advantage.

  • Note in passing that nanoparticles of zinc oxide are also used in sunscreens.

• Note - titanium dioxide in the form of anatase crystals can be converted into nanotubes 10-20 nm in diameter - but I don't their potential uses?

Nanoparticles of silver

• What are nanoparticles of silver? What size are they? What can we do with nanoparticles of silver?

• Silver has always been used as a catalyst to speed up specific reactions in the chemical industry to improve economic efficiency.

  • By using nanoparticles of silver (35-120 nm in size) the effectiveness of the catalyst is greatly improved because the surface area of nanosized silver is so much greater than the larger particles previously used.

  • Its a good example of the 'surface area' rates-kinetic factor for reactions involving a solid catalyst or reactant.

• Nanoparticles of silver are being used in anti-bacterial and anti-fungal agents in biotechnology, bioengineering, the textile industry, water treatment and disinfecting surfaces in the home or hospitals etc.

  • Bactericide and fungicide formulations are being developed to include nanoparticles e.g. of silver, because of their powerful ability to kill bacteria and other organisms.

  • Because of their antibacterial and antifungal properties, potential uses of silver nanoparticles include bone cement, surgical instruments, surgical masks and wound dressings.

  • There is an advantage (at least at the moment!) in using nanoparticles of silver in antibacterial agents, because many bacteria are evolving into strains which are resistant to many antibiotics rendering the ineffective in fighting infections, but so far bacteria don't seem to be resistant to nano-silver formulations!

• Nanoparticles of silver are also used in optics and electronics - important applications but not much, if any, chemistry involved?

Nanoparticles of fat

• Some cosmetics contain 'liposomes', which are fatty nanoparticles .

• Nanoparticles of fatty-like molecules have great potential in the pharmaceutical industry to deliver tiny doses of medicines directly into cells.

  • The use of liposome nanoparticles may enable the efficient delivery of chemotherapeutic agents for cancer treatment. see pdf file

Other examples of the use of nanoparticles and nanowires

• Hip replacement and dental surgery in nanoscience

  • Modern surgical techniques are being improved by using ceramic nanowire coatings based on inorganic materials like titanium dioxide and hydroxyapatite.

  • These inorganic nanowires (extremely fine molecular tubes!) create a more effective surface on implants in hip replacement operations and dental surgery.

  • The nanowire coating is applied to the surface of the implanted component where it is actually implanted in the bone and this ceramic nanowire surface layer encourages bone growth eg the surfaces of the 'wedges' on the ball and socket that are embedded in the bone in hip replacement operations to hold the ball and socket in place.

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WHERE NEXT?

INDEX NANOSCIENCE-NANOCHEMISTRY pages

Part 1. General introduction to nanoscience and commonly used terms explained

Part 2. NANOCHEMISTRY - an introduction and potential applications

Part 3. Uses of Nanoparticles of titanium(IV) oxide, fat and silver

Part 4. From fullerenes & bucky balls to carbon nanotubes

Part 5. Graphene and Fluorographene

Part 6. Cubic and hexagonal boron nitride BN

Part 7. Problems, issues and implications associated with using nanomaterials

see also INDEX SMART MATERIALS PAGES

Keywords: uses applications  liposomes fat sunscreens-sunblockers titanium dioxide silver nanoparticles TiO2 Revising for KS4 Science IGCSE/O level/GCSE Chemistry Information Study Notes for revising for AQA GCSE Science, Edexcel GCSE Science Edexcel IGCSE Chemistry & OCR 21stC Science, OCR Gateway Science, CCEA/CEA GCSE science, WJEC science  (revise courses equal to US grades 9-10) Aid notes for GCE Advanced Subsidiary Level AS Advanced Level A2 IB Revise AQA OCR Edexcel Salters CIE, CCEA/CEA & WJEC advanced level courses for pre-university students (equal to US grade 11 and grade 12 and Honours/honors level courses)

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