Tag Archives: Thomas Pichler

Unraveling carbyne (one-dimensional carbon)

An international group of researchers has developed a technique for producing a record-breaking length of one-dimensional carbon (carbon chain) according to an April 4, 2016 news item on Nanowerk,

Elemental carbon appears in many different modifications, including diamond, fullerenes and graphene. Their unique structural, electronic, mechanical, transport and optical properties have a broad range of applications in physics, chemistry and materials science, including composite materials, nanoscale light emitting devices and energy harvesting materials. Within the “carbon family”, only carbyne, the truly one-dimensional form of carbon, has not yet been synthesized despite having been studied for more than 50 years. Its extreme instability in ambient conditions rendered the final experimental proof of its existence elusive.

An international collaboration of researchers now succeeded in developing a novel route for the bulk production of carbon chains composed of more than 6,400 carbon atoms by using thin double-walled carbon nanotubes as protective hosts for the chains.

An April 4, 2016 University of Vienna press release (also on EurekAlert) provides another perspective on the research,

Even in its elemental form, the high bond versatility of carbon allows for many different well-known materials, including diamond and graphite. A single layer of graphite, termed graphene, can then be rolled or folded into carbon nanotubes or fullerenes, respectively. To date, Nobel prizes have been awarded for both graphene (2010) and fullerenes (1996). Although the existence of carbyne, an infinitely long carbon chain, was proposed in 1885 by Adolf von Baeyer (Nobel laureate for his overall contributions in organic chemistry, 1905), scientists have not yet been able to synthesize this material. Von Baeyer even suggested that carbyne would remain elusive as its high reactivity would always lead to its immediate destruction. Nevertheless, carbon chains of increasing length have been successfully synthesized over the last 50 years, with a record of around 100 carbon atoms (2003). This record has now been broken by more than one order of magnitude, with the demonstration of micrometer length-scale chains.

The new record

Researchers from the University of Vienna, led by Thomas Pichler, have presented a novel approach to grow and stabilize carbon chains with a record length of 6,000 carbon atoms, improving the previous record by more than one order of magnitude. They use the confined space inside a double-walled carbon nanotube as a nano-reactor to grow ultra-long carbon chains on a bulk scale. In collaboration with the groups of Kazu Suenaga at the AIST Tsukuba [National Institute of Advanced Industrial Science and Technology] in Japan, Lukas Novotny at the ETH Zürich [Swiss Federal Institute of Technology] in Switzerland and Angel Rubio at the MPI [Max Planck Institute] Hamburg in Germany and UPV/EHU [University of the Basque Country] San Sebastian in Spain, the existence of the chains has been unambiguously confirmed by using a multitude of sophisticated, complementary methods. These are temperature dependent near- and far-field Raman spectroscopy with different lasers (for the investigation of electronic and vibrational properties), high resolution transmission electron spectroscopy (for the direct observation of carbyne inside the carbon nanotubes) and x-ray scattering (for the confirmation of bulk chain growth).

The researchers present their study in the latest edition of Nature Materials. “The direct experimental proof of confined ultra-long linear carbon chains, which are more than an order of magnitude longer than the longest proven chains so far, can be seen as a promising step towards the final goal of unraveling the “holy grail” of carbon allotropes, carbyne”, explains the lead author, Lei Shi.

Application potential

Carbyne is very stable inside double-walled carbon nanotubes. This property is crucial for its eventual application in future materials and devices. According to theoretical models, carbyne’s mechanical properties exceed all known materials, outperforming both graphene and diamond. Carbyne’s electrical properties suggest novel nanoelectronic applications in quantum spin transport and magnetic semiconductors.

Here’s a link to and a citation for the paper,

Confined linear carbon chains as a route to bulk carbyne by Lei Shi, Philip Rohringer, Kazu Suenaga, Yoshiko Niimi, Jani Kotakoski, Jannik C. Meyer, Herwig Peterlik, Marius Wanko, Seymur Cahangirov, Angel Rubio, Zachary J. Lapin, Lukas Novotny, Paola Ayala, & Thomas Pichler. Nature Materials (2016) doi:10.1038/nmat4617 Published online 04 April 2016

This paper is behind a paywall.

But, there is this earlier and open access version on arXiv.org,

Confined linear carbon chains: A route to bulk carbyne
Lei Shi, Philip Rohringer, Kazu Suenaga, Yoshiko Niimi, Jani Kotakoski, Jannik C. Meyer, Herwig Peterlik, Paola Ayala, Thomas Pichler (Submitted on 17 Jul 2015 (v1), last revised 20 Jul 2015 (this version, v2))

Twirl your ‘carbon’ moustache

I like the imagery they offered in the May 16, 2013 University of Vienna news release on EurekAlert,

Scientists try to understand how to initiate and control the growth of nanomaterials and are exploring different ways to design and build up nanostructures with fine control over shapes. In nature, many organic forms grow bilaterally, that is, symmetrically in two distinct directions. An international team of researchers from the University of Vienna (Austria), the University of Surrey (UK) and the IFW Dresden (Germany) have now achieved such a bilateral formation of inorganic nanomaterials in a controlled environment by implementing a new method.

The scientists pressurized a gas consisting of carbon and iron atoms at an elevated temperature until they observed two arms of carbon atoms spontaneously started growing out of an iron core. When the iron core was small enough, the two carbon arms started spiraling at their ends so that the whole nanostructure bore a striking resemblance with a twirled moustache. [emphasis mine]  “The encouraging insights we gained from our experiments provide a very good starting point for the controlled production of extraordinary new materials with designed nanostructures”, expects Dr. Hidetsugu Shiozawa, leading author of the scientific publication and researcher at the Faculty of Physics at the University of Vienna.

I’ll get back to the twirled moustache in a moment. In the meantime, here’s a citation for and a link to the researchers’ paper,

Microscopic insight into the bilateral formation of carbon spirals from a symmetric iron core
by Hidetsugu Shiozawa, Alicja Bachmatiuk, Andreas Stangl, David C. Cox, S. Ravi P. Silva, Mark H. Rümmeli & Thomas Pichler.  Scientific Reports 3, Article number: 1840
doi: 10.1038/srep01840

The paper is open access, which means finding this illustration (the one I think shows the twirling most clearly) was easy,

Figure 2: Spiralling and kinked bicones produced by a hodographic method using parameters (Δϕ, Δθ, and ΔTi) as a function of the cone length. [downloaded from http://www.nature.com/srep/2013/130514/srep01840/full/srep01840.html]

Figure 2: Spiralling and kinked bicones produced by a hodographic method using parameters (Δϕ, Δθ, and ΔTi) as a function of the cone length. [downloaded from http://www.nature.com/srep/2013/130514/srep01840/full/srep01840.html]

I believe the imagery associated with twirling moustaches, i.e., the villain in a silent movie cackling and twirling his moustaches as he watches over the heroine he’s tied the train tracks await the steaming train headed their way, is well known. Apparently, the trope was not as popular as most of us imagine. I found a fabulous website, The Bioscope; Formerly reporting on the world of early and silent cinema, which tells all in a Nov. 25, 2010 essay,

 It’s a mocking idea of a silent film, the kind of silent film that was never made. All those know [who?] don’t know silent films know one thing about them – that they featured evil villains who twirled their moustaches then tied a hapless female to the railway track. And all those who do know silent films know that such scenes were hackneyed even before films were invented, and the few films that did show them did so as parody.

It’s an issue that comes up time and time again, so let’s try and pin down the historical truth. The idea of an entertainment where someone is tied to a railway track and is rescued in the nick of time certainly predates cinema. The entertainment that put the idea into the popular imagination was an 1867 stage melodrama written by American playwright and theatre manager Augustin Daly entitled Under the Gaslight which featured a man tried to railway tracks who was rescued by a woman before he could be run over by the oncoming train (Victorian theatre revelled in such stage spectaculars).

There’s lots more to the essay along with some great stills and this very charming video animation that manages to poke fun at the trope and the modern UK rail system,

Enjoy!