Scientists from the town of Zelenograd, located in the Moscow region, have developed a unit for building various carbon nanotubes.

Quite recently structures, made of carbon atoms and looking like long hollow tubes with several nanometers in diameter and tens of microns long, were as exotic as pineapples in the Antarctic. Today growing carbon nanotubes is the task for student laboratory workshops. Of course, not any laboratory would be able to perform such works, for it will need the unit for nanotube growth, developed in Zelenograd – Russian “Silicon Valley”.

Unit developers describe their creation as a simple and compact device, which is easy to use. The unit is a reactor oven with 1200 degrees Centigrade and low pressure (nearly vacuum) inside. Mixture of gas and steam is a substrate for nanotube growth. One peculiar feature of this unit is that vapours of ethanol, being a readily available and non-toxic material, serve as a source of carbon. Nanotubes grow like icy flowers on the window glass in winter.

Parameters of nanotubes depend on vapour pressure and structure of cold supporting structure, where carbon atoms condense, forming weird tubes. These supporting structures, which are usually made of metal, are called catalysts, since carbon nanotubes contain no metal, and supporting structures are non-expendable, but not a single nanotube will appear without these structures – instead carbon will turn to amorphous soot.

Reactor oven is not the only part of the unit – except it the unit contains servicing systems. Electronic control unit runs the oven, the pump creates vacuum in the chamber, manometer controls the pressure, and a special device delivers steam-gas mixture to the oven.

Authors have found out that thin (5-10 nm) nickel film is required for growing long (1-30 micron long with diameter between 2 and 40 nanometers) nanotubes, which tend to look like tangled thread. Catalyzing nickel particles from solution of labile nickel compound in ethanol are required for growing nanotubes of 30 nanometer long and 3 nanometer in diameter. As for planar nanotubes, scientists have solved this task, using three-layer film made of vanadium, nickel and again vanadium.

The unit offers magnificent possibilities – anyone can start one of many programmes, stored in the unit’s memory, and get various nanotubes, like a housewife uses a microwave oven to cook profusive variety of meals. The main difference of scientists from the cooks and housewives, whose playground is mainly food, is that materials they synthesize can find application in many fields – from production of nanocomposites to electronics and microsystem equipment. Revolutionary unit is perfect for students to learn, and for serious researchers to study growth processes of nanotubes on catalytic surfaces. And both students and researchers will search for solutions of nature’s mysteries and create new promising materials.

Source:
    Russian Science News
    Nanotechnologies in Russia
    Schoolchildren Science Laboratory
Kizilova Anna