Nanoparticles - SC26 Flashcards
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What are examples of bulk materials?
lumps and powders
what do bulk materials consist of?
huge numbers of atoms
what do nanoparticles consist of ? size?
just a few hundred atoms - 1-100nm in size
what are nanoparticles larger than?
atoms and simple molecules (most 0.1nm in diameter)
what are nanoparticles smaller than?
cells - (most 1000nm long)
are nanoparticles naturally occuring? how does this differ from modern applications?
yes, however modern applicatiins involve manifactured nanoparticles
What does it mean is a substance is described as being nanoparticulate?
the substance consists of nanoparticles
what do the uses of nanoparticulate depend on?
small size of the nanoparticles, and their large surface area to volume ratios
How does titanium dioxide differ from in bulk to nanoparticulate?
in bulk:
* a white solid
* absorbs harmful ultraviolet radiation in sunlight which causes skin cancer
nanoparticulate:
* Trasparent cuz small
* absorbs ultraviolet radiation
why is nanoparticulate titanium dioxide more useful to invisible sunscreens than in bulk?
nanoparticulate is transparent whereas bulk is white solid
why are large surface area to volume ratios of nanoparticles useful?
function as catalysts
why is stain resistant clothes treated with nanoparticulate materials?
nanoparticles catalyse breakdown of dirt so clothes stay clean
why can nanoparticles be considered a hazard to human health and the environment?
small size allows them to be breathed in or pass through cell-surface membranes
why is the large surface area to volume ratio of nanoparticles a concern?
allow them to catalyse harmful reactions or carry toxic substances bound to their surfaces
why are nanoparticle risks difficult to determine?
modern nanoparticulate materaisl have not been in use for long
