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Observations: rolling versus sliding

Observations beyond the range of the naked eye require more deliberate and cautioned interpretation of what isobserved. Specifically, factual and accurate information must be discerned out of various interferences that can lead tounsubstantiated conclusions. The Tour group had to surmount these uncertainties to conclusively show that the nanocars underwentrolling, rather than sliding, translational motion.

Nanocar translational movement across a gold surface at 200°C. The pivoting of the molecule’s motion is due to out-of-sync rotation of wheel movement. Thepicture indicated path occurred over a minute period (images captured ever minute by STM). Reprinted with kindpermission from Dr. Kevin Kelly<picture courtesy of Rice University Office of Media Relations>.

The choice of a gold surface enabled temperature dependent adhesion to the surface, and allowed targetedobservation of specific molecules. In the picture to the left, you see several nanocars spread out along the Au(111) surface. As theresearchers increased the temperature to 200°C, the cars began to move at such a rate that they noticeably displaced from their originalposition in a period of one minute (figure 8). This indicates that 200°C is a viable temperature for imaging nanocars on gold with STM. However, imaging of the cars at temperatures above 225°C is currently impossible due to the rapid motion of the molecules at thattemperature. The nanocars are moving too quickly to be imaged by the one-minute capture rate of the STM. Once the system was heated to300-350°C, the car began to decompose. These observations indicated that motion of the nanocars was dependent on temperature.

It was also observed that the cars did not exclusively undergo translational motion, but also rotated. In theimage to the right, it can be observed that the cars pivot as they move across the frame, changing direction without moving forward. TheTour Group explained this rotation as an inability to synchronize the rotation of each wheel.

The Tour Group also observed three-wheeled molecules, or trimers, which they found useful inproving rotational motion of the C60 molecules. If the cars’ movement were in fact due to rotation, then the trimer would not be able tomove translationally due to the fact that the three wheels cannot rotate in a coordinated manner, that is no two wheels can rotate thesame parallel plane. This supports the idea that the C60 molecules are rotating, as opposed to sliding. To strengthen their assertion, theresearchers heated a sample of the trimer molecules on the same gold surface to 225°C—a temperature at which the four-wheeled molecules rapidly moved out of the scanning range of the STM. Upon doing so,they observed that the trimers did not undergo significant translational motion, and remained within nanometers of their originalposition. This showed that both the wheels and axels of the trimer and nanocar allow for rotational motion, therefore substantiating theassertion that translational motion of the nanocar is due to rolling.

The researchers used an STM to pull the nanocar in order to see if there was preferential motion (ie. Due torolling). When the molecules were pulled perpendicular to the axles (Figure 9; frame a) the molecule moved in the direction of thepull. But, pulling parallel to the axles resulted in no translational motion in the direction of the pull (frame b). Lastly, by pullingperpendicular to the axles, the nanocar resumed its forward path (frame c).

Translational Motion of Pulled Nanocars on Gold Surface at 200°C. Frame (a) depicts the movement of a nanocar pulled perpendicular to its axles. Frame (b) indicates theinhibited motion that results from pulling parallel to the axles. Frame (c) is another instance of a pulling force perpendicular tothe axles. Reprinted with kind permission from Dr. Kevin Kelly<picture courtesy of Rice University Office of Media Relations>.

These experiments carried out by the Tour Group combined to substantiate the claim that the nanocars wererolling on the C60 wheels as opposed to sliding. This observation designates the molecule as the first nanocar capable of executing apredetermined, engineered motion. These experiments lay down a foundation of knowledge on the molecular mechanics of motion.Particularly, these experiments conclusively demonstrate rolling motion of the C60 on gold surfaces at a given temperature. This marksthe first step in a greater understanding of molecular motion as it applies to molecular manufacturing.

The future of the development of molecular manipulation

Molecular manipulation as a science has developed in steps. Its early steps involved movement of atoms and molecules,along with the ability to observe those movements. Later came engineered molecular components that carried out predeterminedfunctions, such as bearings and axles. At the present, nanocars are an example of the developments in motility and function of integratedcomponents that serve a unified purpose. But more importantly, nanocars are an indicator of developments to come. They are usheringin an era of deliberate and controlled motion at the molecular level.

Questions & Answers

how can chip be made from sand
Eke Reply
is this allso about nanoscale material
are nano particles real
Missy Reply
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
where is the latest information on a no technology how can I find it
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
has a lot of application modern world
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
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Source:  OpenStax, Nanotechnology: content and context. OpenStax CNX. May 09, 2007 Download for free at http://cnx.org/content/col10418/1.1
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