Fluids trapped in small spaces occupy a prominent place in science and technology, and understanding their properties is critical to progress in fields ranging from cellular biology to nanoscale device engineering. Such confined fluids often behave differently than bulk samples having the same chemical potential or average density. Properties affected by containment include
(i) how the particles accumulate,
(ii) the way the fluid responds to quasi-static heating or
(iii) the rapidity with which the fluid relaxes, diffuses, conducts heat or flows.
There are quantitatively exact theories for the first two types of properties, but even the qualitative rules for estimating the third type have been evasive. During the last decade, fluid research in nano-confined geometries has received considerable attention as a result of its wide applications in different fields. Several nano-confined systems such as water and ionic liquids along with an equally impressive array of nano-configuration media such as carbon nano-tube, graphene and graphene oxide have received increasing interest in recent years. Water is the first system that has been revised in this article, due to its important role in the phenomena of transport in the environmental sciences. Water is often considered as a highly nano-confined system, due to its reduction to a few layers of water molecules between the extended surface of large macro-molecules. The second system discussed here is ionic liquids, which have been extensively studied in the movement of modern green chemistry. Taking into account the great importance of ionic liquids in the industry, and also its oil / water counterpart, nano-confined ionic liquid system has become an important field of research with many fascinating applications. In addition, the molecular dynamics simulation method is one of the main tools in the theoretical study of water and ionic liquids in nano-conflation, which has increasingly been linked with experimental procedures.