Piezoelectric effect in liquid

(MainsGS3:Science and Technology- developments and their applications and effects in everyday life.)

Context:

• Recently, for the first time, scientists have reported evidence of the piezoelectric effect in liquids which earlier believed to be found in solids only.
• 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.

About 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.

Effect in liquids:

• 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.

Possible applications:

• The discovery opens the door to applications that have previously not been accessible with solid-state materials, and [room-temperature ionic liquids] are more readily recyclable and in many instances pose fewer environmental issues than many currently used piezoelectric materials.
• The liquids also displayed the inverse piezoelectric effect: they became distorted when an electric charge was applied. 
• This effect could be used to control how the liquids bent light passing through them by passing different currents through them. 
• That is, using this simple control mechanism, vials of these liquids could be lenses with dynamic focusing abilities.

Conclusion:

• Having a theory to explain the liquids’ behaviour could reveal why these liquids behave the way they do, which could in turn reveal better ways to manipulate them, and develop newer applications.