Graphene: Supermaterial Goes Superpermeable
Discovery
Wonder material graphene has revealed another of its extraordinary properties -- University of Manchester researchers have found that it is superpermeable with respect to water.
Graphene's Properties
It is the thinnest known material in the universe and the strongest ever measured.
It conducts electricity and heat better than any other material.
It is the stiffest one too and, at the same time, it is the most ductile.
Graphene Oxide ( The Discovery)
Graphene oxide is the same graphene sheet but it is randomly covered with other molecules such as hydroxyl groups OH-.
Graphene oxide sheets stack on top of each other and form a laminate.
The researchers prepared such laminates that were hundreds times thinner than a human hair but remained strong, flexible and were easy to handle.
Graphene Oxide's Amazing Properties
When a metal container was sealed with such a film(of graphene oxide), even the most sensitive equipment was unable to detect air or any other gas, including helium, to leak through.
It came as a complete surprise that, when the researchers tried the same with ordinary water, they found that it evaporates without noticing the graphene seal.
Water molecules diffused through the graphene-oxide membranes with such a great speed that the evaporation rate was the same independently whether the container was sealed or completely open.
Dr Rahul Nair, who was leading the experimental work, offers the following explanation
Graphene oxide sheets arrange in such a way that between them there is room for exactly one layer of water molecules.
They arrange themselves in one molecule thick sheets of ice which slide along the graphene surface with practically no friction.
If another atom or molecule tries the same trick, it finds that graphene capillaries either shrink in low humidity or get clogged with water molecules.
Uses (Obvious)
This unique property can be used in situations where one needs to remove water from a mixture or a container, while keeping in all the other ingredients
Just for a laugh, we sealed a bottle of vodka with our membranes and found that the distilled solution became stronger and stronger with time.
BUT.....
The Manchester researchers report this experiment in their Science paper, too, but they say they do not envisage use of graphene in distilleries, nor offer any immediate ideas for applications.