PIEZOELECTRIC
EFFECT – SCI & TECH
News:
Scientists spot
piezoelectric effect in liquids for the first time
What's
in the news?
●
For the first time, scientists have reported evidence of the piezoelectric
effect in liquids.
●
The effect has been known for 143 years
and in this time has been observed only
in solids.
●
The new finding challenges the theory that
describes this effect as well as opens the door to previously unanticipated
applications in electronic and mechanical systems.
Key
takeaways:
●
The effect was found in pure
1-butyl-3-methyl imidazolium bis(trifluoromethyl-sulfonyl) imide and
1-hexyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide – both ionic
liquids (i.e. liquids made of ions instead of molecules) at room temperature.
Piezoelectric
effect:
●
In the piezoelectric effect, a body develops an electric current when it
is squeezed.
●
Quartz
is the most famous piezoelectric crystal - it is used in this capacity in
analog wristwatches and clocks.
●
Such crystals are also used in cigarette
lighters, electric guitars, TV remote controls, audio transducers, and other
instruments where converting mechanical stress to a current is useful.
Why
is the effect in liquids surprising?
●
The reason the piezoelectric effect has
only been expected in solids thus
far is that the body being squeezed needs to have an organised structure, like the pyramids of quartz.
●
Liquids
don’t have such structure; instead, they take the shape of
their container.
●
Physicists explain the effect using a
combination of Hooke’s law – that
the force required to squeeze an object is linearly (i.e. non-exponentially)
proportional to the amount of squeezing – and the properties of dielectric
materials. These are materials that don’t conduct electricity but whose
electrons are still mildly affected by an electric field.