Post Tagged with: "Ben Feringa"


Stephen J. Ebbens

Jonathan Howse

The current state of the art in nanopropulsion devices was recently reviewed by Ebbens and Howse in an article last Friday.[SoftMatter] A short summary of the nano- systems is presented below with video action shots when I could find them.

The Whitesides

Catalyst: Pt
Fuel: H2O2
Propulsion: Bubble propulsion
Terrain: Aqueous meniscus
Max Speed: 2 cm/s
Mitch’s Name: The Karl Benz (since it was the first)
Article: Autonomous Movement and Self-Assembly

The Sen-Mallouk-Crespi

Catalyst: Pt
Fuel: H2O2
Propulsion: Self electrophoresis/Interfacial tension
Terrain: Settled near boundary in aqueous solution
Max Speed: 6.6 um/s
Mitch’s Names: The Ford Mustang of nanopropulsion. (It is a hot rod, get it?)
Article: Catalytic Nanomotors: Autonomous Movement of Striped Nanorods

The Jones-Golestanian

Catalyst: Pt
Fuel: H2O2
Propulsion: Pure self diffusiophoresis
Terrain: Free aqueous solution
Max Speed: 3um/s
Mitch’s Name: The Volkswagen Beetle
Article: Self-Motile Colloidal Particles: From Directed Propulsion to Random Walk

The Mano-Heller

Catalyst: Glucose oxidase and Biliruben oxidase
Fuel: Glucose
Propulsion: Self electrophoresis
Terrain: Aqueous meniscus
Max Speed: 1 cm/s
Mitch’s Name: The Komatsu Truck (because it is huge)
Article: Bioelectrochemical Propulsion

The Feringa

Catalyst: Synthetic catalse
Fuel: H2O2
Propulsion: Bubble/interfacial
Terrain: Acetonitrile solution
Max Speed: 35 um/s
Mitch’s Name: The F150 (has some exhaust issues)
Article: Catalytic molecular motors: fuelling autonomous movement by a surface bound synthetic manganese catalase

The Sen-Mallouk

Catalyst: Pt (CNT) (+cathodic reactions at Au)
Fuel: H2O2/N2H4
Propulsion: Self electrophoresis
Terrain: Settled near boundary in aqueous solution
Max Speed: 200 um/s
Mitch’s Names: The Ford Mustang GT (has more kick than the regular version)
Article: Bipolar Electrochemical Mechanism for the Propulsion of Catalytic Nanomotors in Hydrogen Peroxide Solutions

The Feringa v2

Catalyst: Glucose oxidase and catalse
Fuel: Glucose
Propulsion: Local oxygen bubble formation
Terrain: Free aqueous buffer solution
Max Speed: 0.2–0.8 um/s
Mitch’s Name: The Chevrolet Nova (more hot rod action)
Article: Autonomous propulsion of carbon nanotubes powered by a multienzyme ensemble

The Gibbs-Zhao

Catalyst: Pt
Fuel: H2O2
Propulsion: Bubble release mechanism
Terrain: Aqueous solution
Max Speed: 6 um/s
Mitch’s Name: The Rover
Article: Autonomously motile catalytic nanomotors by bubble propulsion

The Bibette

Engine: External magnetic field
Propulsion: Flagella
Terrain: Aqueous solution
Max Speed: unknown
Mitch’s name: The BMW Mini E (because there is no such thing as a magnetic car)
Article: Microscopic artificial swimmers

The Sagués

Engine: External magnetic field
Propulsion: Doublet rotation coupling with boundary interactions
Terrain: Settled near boundary in aqueous solution
Max Speed: 3.2 um/s
Mitch’s Name: The Smart ED
Article: Magnetically Actuated Colloidal Microswimmers

The Fischer

Engine: External magnetic field
Propulsion: Propeller drive
Terrain: Aqueous solution
Max Speed: 40 um/s
Mitch’s Name:
Article: Controlled Propulsion of Artificial Magnetic Nanostructured Propellers

The Najafi-Golestanian

Engine: Conformation changes in linking units
Propulsion: Time irreversible translations
Terrain: Free solution
Max Speed: ?
Mitch’s Name: The Eternal Concept Car
Article: Propulsion at low Reynolds number

Some devices that were not included by the authors of the review article, but should definitely be included in any list like this are below:

The Gracias

Engine: External magnetic field
Propulsion: Brute Force
Terrain: Aqueous solution
Max Speed: ?
Mitch’s Name: The Truck Cranes
Article: Tetherless thermobiochemically actuated microgrippers

Tetherless Microgrippers Grabs Tissue SampleWatch today’s top amazing videos here

The Nelson

Engine: External electromagnetic fields
Propulsion: Flagella
Terrain: ?
Max Speed: 18 um/s
Mitch’s Name: The Tesla Roadster (simply awesome)
Article: Characterizing the Swimming Properties of Artificial Bacterial Flagella

Artificial SpermWatch more funny videos here

Link to Review Article: In pursuit of propulsion at the nanoscale


By January 16, 2010 5 comments materials chemistry

Light Powered Motor and Experiment Vlogging

Most of you probably read the last issue of C&EN with the spiffy carrot loving cover story (good for me because I love carrots, but have never tried those ugly-looking BetaSweets). Inside, however, there was an extremely interesting little article in the “Science and Technology Concentrates” about light-driven pulleys turning a plastic motor.

Now photo mobile polymer materials have been around for quite a while, at least from my perspective seeing as how I wasn’t even in highschool when the big Nature paper came out. Some might remember the Nature 1999 Sep 9;401(6749):152-5 Koumura et al. paper titled “Light-Driven monodirectional molecular rotor”. Although back then, the rotation was monodirectional around a C-C double bond in a chiral, helical alkene. It was activated by UV light or a change in temperature and the motor was based on light-induced cis-trans isomerizations that caused 180 degree rotations followed by thermally controlled helicity inversions, which basically nullified half a rotation. Four isomerizations resulted in 1 complete cycle.

Well this was pretty darn cool but we’ve come a long way since then. As expected, and as Koumura said, structurally modified chiral alkenes played the central role in the development of these molecular motors that were beginning to interest the MEMS people (MEMS stands for Micro-Electromechanical Systems…I am pretty sure).

In J Am Chem Soc. 2003 Dec 10;125(49):15076-86, ter Wiel MK et al. introduced the worlds smallest artificial light-driven motor using 28 carbon atoms and 24 hydrogen atoms.

Reprinted with permission from American Chemical Society: Journal of the American Chemical Society (Nov. 2003).

It also had a dramatic speed increase over the original designs, at a whopping 18s half-life at the fastest step. Even if it wasn’t going to be turning any relevant loads any time soon, it was a dramatic improvement over the original concept 4 years earlier. Still, even though some clever O-chem tricks made the motor better, it still operated on the same 4-step cycle that Koumura’s did back in 99′. Even recently, in Org. Biomol. Chem., 2008, 6, 507 – 512, DOI: 10.1039/b715652a, Pollard et al. report on substituting naphthalene moieties for phenyl moieties, in order to better control the speed of the motors, and to enable the design and synthesis of more complex systems.

Meanwhile, the MEMS people came up with interesting designs similar to this:

“A five micron wide resin structure, with a shape resembling a lawn sprinkler, rotates when illuminated by a laser beam. Tiny rotors like this one may someday power micromechanical systems (MEMS), or twist molecules to measure their mechanical properties.” Reported by: Péter Galajda; Pál Ormos, Applied Physics Letters, 8 January, 2001.

There was quite a bit of work done focusing on creating rotors that responded to laser light, although the practical applications of such devices aren’t as numerous as the devices that…well don’t require a coherent, collimated, polarized light beam to operate. Or at least they weren’t until Peidong Yang’s came around with his nanolasers.

Unfortunately, all of these motors share the drawback of being unidirectional. It was until recently, with Ikeda’s et al. paper in Angew. Chem. Int. Ed. 2008, 47, 4986, that a very cool and new method for directly converting light into mechanical work. Basically they drew on the fact that azobenzene derivatives, when incorporated into liquid crystals, can have an isotropic phase transition induced isothermally by irradiation with UV light to cause trans–cis photoisomerization, and that the reverse transition can be induced by irratiation with visible light to cause cis-trans back-isomerization. This photoinduced phase transition
led to successfully reversible deformations of liquid crystal elastomers containing azobenzene chromophores just by changing the wavelength of the incident light.

Now this by itself doesn’t a motor make. There was one large problem: the liquid crystal elastomer had to be made into a film or “belt” for a motor. However, the LCE film by itself wasn’t mechanically strong enough and tended to crack after short light irradiation at high intensities. So to fix this issue, they simply laminated the LCE film with flexible polyethylene sheets. I love this type of simple solution to what could have been a convoluted problem. This is very much like what Mitch and I tend to do.

*Note that they did do a study of increasing light intensity and it’s correlation to the mechanical force generated by the film. They found that “the maximum force and the increment rate of the generated force are enhanced with an increase of the light intensity.”*

So what happened? Well check this out:

Thats right. That is an actual light-driven motor NOT on the micro-scale. The diameter of those pulleys are 10mm on the left and 3 mm on the right. Sure it isn’t going to be competing in any races at the moment, but it could still be amazingly useful in the future. Light, straight to DC? That would be pretty darn awesome.

PS. Tomorrow is the first day of the experiment Mitch and I are running. Since we can, we will be broadcasting the first live cyclotron experiment out over the interweb. This may be one of the first live nuclear physics experiments broadcasted. Other then that, it is just cool. SO we will have it up all 24 hours as a “live vlog”.

Feel free; hell feel obligated to stop by, leave a comment, chat, ask questions, offer constructive or destructive criticism, whatever. Maybe ACS will pick this up as a new way to present new research: present it as it happens! Live!!!