bonding, structure, and properties Flashcards
Thermochromic
define - change colour at diff temps
use - thermometer strips
photochromic
define - change colour at diff light intensities
use - sunglasses
polymer gels
define - can absorb a large volume of liquid
use - nappies
shape memory alloys
define - if deformed, returns to og shape when heated
use - spectacle frames
shape memory polymer
define - if deformed, return to og shape when heated
use - car bumpers
define alloy
solid mixture of different metals
define smart materials
materials whose properties change in response to their environment
name 2 nanomaterials
nano titanium dioxide and nano silver
define nanomaterials
materials with particle diameters of less than around 100 nanometers. have different properties compared to ‘bulk’ materials. risks of humans exposure not fully known.
nano titanium dioxide
property - absorbs ultra-violet light
use - sunscreen
nano silver
properties - antibacterial
use - antibac creams and coatings
metallic bonding strength
the larger the ion charge, the stronger the metallic bond.
graphite melting point and why
high because it has strong covalent bonds that need a lot of energy to break
graphite electrical conductivity
conducts electricity because it has delocalised electrons (4th electron of each carbon atom becomes delocalised)
graphite uses and why
uses - pencils, lubricant
why - the layers can slide over each other because there are no covalent bonds between them, making it soft and slippery
