Russian scientists from the Institute of Applied Mechanics have made a significant contribution to the field of reusable nano-containers.

Nano-capsules are studied all around the world as advanced elements for new information-carrying media – they have larger capacity and need less energy for information recording and deleting. These elements are also expected to contribute to renewal of radioelectronic hardware components and to progress in diagnostics and precise drug delivery.

Nano-capsules, also known as nano-containers, can be divided into two main groups – disposable, which break up, releasing active substances, and reusable, which can be opened and closed according to process regulations. Reusable nano-containers are usually made of so-called “peapod” carbon nano-structures. These structures are nanotubes, which contain one or more fullerenes inside their cavities. “Peapod” carbon nano-structures are considered to be a good prototype for an “ideal nano-container”, inner cavity of which is used for storing required substance, and fullerene works like a locking nanoparticle, which prevents stored substance form leaving a container.

 

 

Russian physicists from Ural branch of Russian Academy of Sciences made a step forward in solving the problem of nano-containers. The point is that nano-containers, which work in changing thermodynamic environments, can under normal conditions store that amount of hydrogen (1.6 mass percent), which was absorbed under loading conditions (temperature of 77 K, pressure of 10 megapascals). Hydrogen usually escapes from nano-containers of this type, when temperature gets higher. Nano-containers with charged locking element (fullerene) are able to store hydrogen despite changing thermodynamic parameters. The only thing that defines stages of absorbing, storing and releasing of its contents is strength of external electrostatic field. In normal environment bottle-like nano-containers of increased capacity, which have charged locking element, are able to store 9 mass percent of methane, adsorbed under conditions of normal temperature and pressure of 10 megapascals.

Authors have suggested various designs of nano-containers for storing gases, which show specific directions for further usage and development of synthesis techniques for new highly effective adsorbing agents. In order to synthesize nano-capsules or nano-containers of complex structural forms, engineers use already existing technologies for forming nano-structural carbon by means of radiation or particle flows. These technologies cause changes in structure, morphology and various properties of carbon materials – electronic, mechanical and chemical properties. Mentioned technologies make defects or holes in nano-tubes with angstrom accuracy, change nanotube diameters, perform “welding” of various nanotubes, resulting in “Y” or “T”-shaped joints. Existing tools and techniques of direct changes of nano-structures are the basis for future facilities, aimed at creating nano-capsules of complex structures.

Source: Physics Institute of Russian Academy of Science

Kizilova Anna