Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Molecular motors: Power much less than expected?

Researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw have measured power generated by molecular machines -- collectively rotating molecules of liquid crystals in a monomolecular layer on the surface of water.

Credit: IPC PAS, Grzegorz Krzyżewski
Researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw have measured power generated by molecular machines -- collectively rotating molecules of liquid crystals in a monomolecular layer on the surface of water. Credit: IPC PAS, Grzegorz Krzyżewski

Abstract:
An innovative measurement method was used at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw for estimating power generated by motors of single molecule in size, comprising a few dozens of atoms only. The findings of the study are of crucial importance for construction of future nanometer machines - and they do not instil optimism.

Molecular motors: Power much less than expected?

Warsaw, Poland | Posted on August 28th, 2013

Nanomachines are devices of the future. Composed of a very little number of atoms, they would be in the range of billionth parts of a meter in size. Construction of efficient nanomachines would lead most likely to another civilization revolution. That's why researchers around the world look at various molecules trying to put them at mechanical work.

Researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw were among the first to have measured the efficiencies of molecular machines composed of a few dozen of atoms. "Everything points to the belief that the power of motors composed of single, relatively small molecules is considerably less than expected", says Dr Andrzej Żywociński from the IPC PAS, one of the co-authors of the paper published in the "Nanoscale" journal.

Molecular motors studied at the IPC PAS are molecules of smectic C*-type liquid crystals, composed of a few tens of atoms (each molecule is 2.8 nanometer long). After depositing on the surface of water, the molecules, under appropriate conditions, form spontaneously the thinnest layer possible - a monomolecular layer of specific structure and properties. Each liquid crystal molecule is composed of a chain with its hydrophilic terminal anchored on the surface of water. A relatively long, tilted hydrophobic part protrudes over the surface. So, monomolecular layer resembles a forest with trees growing at certain angle. The free terminal of each chain includes two crosswise arranged groups of atoms with different sizes, forming a two-blade propeller with blades of different lengths. When evaporating water molecules strike the "propellers", the entire chain starts to rotate around its "anchor" due to asymmetry.

Specific properties of liquid crystals and the conditions of experiment give rise to an in-phase motion of adjacent molecules in the monolayer. It is estimated that "tracts of the forest" of up to one trillion (10^12) molecules, forming areas of millimeter sizes on the surface of water, are able to synchronise their rotations. "Moreover, the molecules we studied were rotating very slowly. One rotation could be as long as a few seconds up to a few minutes. This is a much desired property. Would the molecules be rotating with, for instance, megahertz frequencies, their energy could be hardly transferred on larger objects", explains Dr Żywociński.

Earlier power estimations for molecular nanomotors were related either to much larger molecules, or to motors powered by chemical reactions. In addition, these estimations did not account for the resistance of the medium where the molecules worked.

Free, collective rotations of liquid crystal molecules on the surface of water can be easily observed and measured. Researchers from the IPC PAS checked how the speed of rotation changes as a function of temperature; they estimated also changes in (rotational) viscosity in the system under study. It turned out that the energy of single molecule motion generated during one rotation is very low: just 3.5•10^-28 joule. This value is as many as ten million times lower than the thermal motion energy.

"Our measurements are a bucket of cold water for designers of molecular nanomachines", notices Prof. Robert Hołyst (IPC PAS).

In spite of generating low power, rotating liquid crystal molecules can find practical applications. This is due to the fact that a large ensemble of collectively rotating molecules generates a correspondingly higher power. Moreover, a single square centimeter of the surface of water can accommodate many such ensembles with trillions of molecules each.

The same research at the IPC PAS included also a comparison of power generated by rotating molecules of liquid crystals with the power of a single biological motor - a very large molecule known as adenosinetriphosphatase (ATPase). The enzyme plays a role of sodium-potassium pump in animal cells. With appropriate calculations it was estimated that the density of energy generated in a volume unit was about 100,000 times higher for ATPase than for rotating liquid crystals.

"It took millions of years for evolution to develop such an efficient molecular pump. We, humans, have been working with molecular machines for a couple or maybe a dozen of years only", comments Prof. Hołyst and adds: "Give us just a bit of time".

This press release was prepared thanks to the NOBLESSE grant under the activity "Research potential" of the 7th Framework Programme of the European Union.

####

About Institute of Physical Chemistry of the Polish Academy of Sciences
The Institute of Physical Chemistry of the Polish Academy of Sciences was established in 1955 as one of the first chemical institutes of the PAS. The Institute's scientific profile is strongly related to the newest global trends in the development of physical chemistry and chemical physics. Scientific research is conducted in nine scientific departments. CHEMIPAN R&D Laboratories, operating as part of the Institute, implement, produce and commercialise specialist chemicals to be used, in particular, in agriculture and pharmaceutical industry. The Institute publishes approximately 200 original research papers annually.

For more information, please click here

Contacts:
Dr. Andrzej Zywocinski

Copyright © Institute of Physical Chemistry of the Polish Academy of Sci

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Laboratories

Tiny carbon nanotube pores make big impact October 29th, 2014

New evidence for an exotic, predicted superconducting state October 27th, 2014

National Synchrotron Light Source II Achieves 'First Light' October 23rd, 2014

Novel Rocket Design Flight Tested: New Rocket Propellant and Motor Design Offers High Performance and Safety October 23rd, 2014

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

Display technology/LEDs/SS Lighting/OLEDs

Strengthening thin-film bonds with ultrafast data collection October 23rd, 2014

QD Vision Wins Prestigious Presidential Green Chemistry Challenge Award from the U.S. Environmental Protection Agency October 16th, 2014

Beyond LEDs: Brighter, new energy-saving flat panel lights based on carbon nanotubes - Planar light source using a phosphor screen with highly crystalline single-walled carbon nanotubes (SWCNTs) as field emitters demonstrates its potential for energy-efficient lighting device October 14th, 2014

Govt.-Legislation/Regulation/Funding/Policy

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

'Electronic skin' could improve early breast cancer detection October 29th, 2014

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Tiny carbon nanotube pores make big impact October 29th, 2014

Molecular Machines

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Optimum inertial design for self-propulsion: A new study investigates the effects of small but finite inertia on the propulsion of micro and nano-scale swimming machines July 29th, 2014

Breakthrough laser experiment reveals liquid-like motion of atoms in an ultra-cold cluster: University of Leicester research team unlocks insights into creation of new nano-materials July 25th, 2014

NIST shows ultrasonically propelled nanorods spin dizzyingly fast July 22nd, 2014

Molecular Nanotechnology

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Fast, cheap nanomanufacturing: Arrays of tiny conical tips that eject ionized materials could fabricate nanoscale devices cheaply October 4th, 2014

Nano-bearings on the test bench: Fullerene spheres can be used to slide in the nanoworld October 3rd, 2014

Penn Team Studies Nanocrystals by Passing Them Through Tiny Pores September 26th, 2014

Announcements

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Iranians Present Model to Predict Photocatalytic Process in Removal of Pollutants October 30th, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

NanoNews-Digest
The latest news from around the world, FREE





  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE