Tag Archives: collapsing boundaries

A closer look at the interface between water and solid surfaces sparks memories of the water/air interface

Researchers at China’s Peking University have developed a technique for taking the closest look possible at the interface  between water and solid surfaces according to a Jan. 10, 2014 news item on Nanowerk,

The interaction of water with the surfaces of solid materials is ubiquitous. Many remarkable physical and chemical properties of water/solid interfaces are governed by H-bonding interaction between water molecules. As a result, the accurate description of H-bonding configuration and directionality is one of the most important fundamental issues in water science. Ideally, attacking this problem requires the access to the internal degrees of freedom of water molecules, i.e. the O-H directionality. However, resolving the internal structure of water has not been possible so far despite massive efforts in the last decades due to the light mass and small size of hydrogen.

Recently, the teams led by Professor Ying Jiang and Professor Enge Wang of International Center for Quantum Materials (ICQM) of Peking University succeeded to achieve submolecular-resolution imaging of individual water monomers and tetramers adsorbed on a Au [gold]-supported NaCl [sodium chloride](001) film at 5 K, using a cryogenic scanning tunneling microscope (STM).

The Jan. 9, 2014 University of Peking news release, which originated the news item, provides more detail,

… They first decoupled electronically the water molecule from the metal substrate by inserting an insulating NaCl layer and then employed the STM tip as a top gate to tune controllably the molecular density of states of water around the Fermi level. These key steps enabled them to image the frontier molecular orbitals which are spatially locked together with the geometric structures of water molecules. Notably, they were able to discriminate in real space the orientation of water monomers and the H-bonding directionality of water tetramers based on the submolecular-resolution orbital images.

This work opens up the possibility of determining the detailed topology of H-bonded networks at water/solid interfaces with atomic precision, which is only possible through theoretical simulations in the past. The ability to resolve the O-H directionality of water provides further opportunities for probing the dynamics of H-bonded networks at atomic scale such as H-atom transfer and bond rearrangement. In addition, the novel orbital-imaging technique developed in this work reveals new understanding of STM experiments and may be applicable to a broad range of molecular systems and materials.

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

Real-space imaging of interfacial water with submolecular resolution by Jing Guo, Xiangzhi Meng, Ji Chen, Jinbo Peng, Jiming Sheng, Xin-Zheng Li, Limei Xu, Jun-Ren Shi, Enge Wang, & Ying Jiang. Nature Materials (2014) doi:10.1038/nmat3848 Published online 05 January 2014

This paper is behind a paywall although you can get a preview via ReadCube Access.

As noted in the headline, this work sparked a memory of research conducted on the water/air interface and the discovery that the boundary between water and air is not as distinct as was believed. (I have a longstanding interest in boundaries, which often have an arbitrary nature.) From the 2011 (?) news item on Softpedia,

The question of where water stops and where air begins is a very old, and difficult-to-answer one. Experts have been trying to do so for years, and now it would appear that they finally have an answer. The layer separating the two is as thin as the distance between two atoms in a hydrogen molecules.

At the topmost layer of water, in an ocean for example, water (H2O) molecules are having a real problem – they cannot really decided whether to exist as gas or liquid. As such, one of the two hydrogen atoms remains in the water, while the second ones pokes out into the air.

Physicists now call this the layer of molecular ambiguity, and say that it has little to no effect on the way water below this level behaves. …

Interestingly, just one molecule beneath this first layer of H2O molecules, the rest of the water behaves as if nothing is going on in the layers above. This discovery is critically important for many fields of research, including for example atmospheric chemistry.

“In some ways this is a negative result. Sometimes a negative result can be very positive,” says Pavel Jungwirth, a scientist at the Academy of Sciences of the Czech Republic, in Prague. …

With the new data, says University of Victoria [located in British Columbia, Canada] physical chemist Dennis Hore, scientists will be able to refine models seeking to explain how water interacts with other chemicals within living cells. …

There’s a link to and a citation for the 2011 paper,

Hydrogen bonding at the water surface revealed by isotopic dilution spectroscopy by Igor V. Stiopkin, Champika Weeraman, Piotr A. Pieniazek, Fadel Y. Shalhout, James L. Skinner, & Alexander V. Benderskii. Nature 474, 192–195 (09 June 2011) doi:10.1038/nature10173 Published online 08 June 2011

This paper is behind a paywall although you can get a preview via ReadCube Access.

Zombies, brains, collapsing boundaries, and entanglements at the 4th annual S.NET conference

My proposal, Zombies, brains, collapsing boundaries, and entanglements, for the 4th annual S.NET (Society for the Study of Nanoscience and Emerging Technologies) conference was accepted. Mentioned in my Feb. 9, 2012 posting, the conference will be held at the University of Twente (Netherlands) from Oct. 22 – 25, 2012.

Here’s the abstract I provided,

The convergence between popular culture’s current fascination with zombies and their appetite for human brains (first established in the 1985 movie, Night of the Living Dead) and an extraordinarily high level of engagement in brain research by various medical and engineering groups around the world is no coincidence

Amongst other recent discoveries, the memristor (a concept from nanoelectronics) is collapsing the boundaries between humans and machines/robots and ushering in an age where humanistic discourse must grapple with cognitive entanglements.

Perceptible only at the level of molecular electronics (nanoelectronics), the memristor was a theoretical concept until 2008. Traditionally in electrical engineering, there are three circuit elements: resistors, inductors, and capacitors. The new circuit element, the memristor, was postulated in a paper by Dr. Leon Chua in 1971 to account for anomalies that had been experienced and described in the literature since the 1950s.

According to Chua’s theory and confirmed by the research team headed by R. Stanley Williams, the memristor remembers how much and when current has been flowing. The memristor is capable of an in-between state similar to certain brain states and this capacity lends itself to learning. As some have described it, the memristor is a synapse on a chip making neural computing a reality and/or the possibility of repairing brains stricken with neurological conditions. In other words, with post-human engineering exploiting discoveries such as the memristor we will have machines/robots that can learn and think and human brains that could incorporate machines.

As Jacques Derrida used the zombie to describe a state that this is neither life nor death as undecidable, the memristor can be described as an agent of transformation conferring robots with the ability to learn (a human trait) thereby rendering them as undecidable, i.e., neither machine nor life. Mirroring its transformative agency in robots, the memristor could also confer the human brain with machine/robot status and undecidability when used for repair or enhancement.

The memristor moves us past Jacques Derrida’s notion of undecidability as largely theoretical to a world where we confront this reality in a type of cognitive entanglement on a daily basis.

You can find the preliminary programme here.  My talk is scheduled for Thursday, Oct. 25, 2012 in one of the last sessions for the conference, 11 – 12:30 pm in the Tracing Transhuman Narratives strand.

I do see a few names I recognize, Wickson, Pat (Roy)  Mooney and Youtie. I believe Wickson is Fern Wickson from the University of Bergen last mentioned here in a Jul;y 7, 2010 posting about nature, nanotechnology, and metaphors. Pat Roy Mooney is from The ETC Group (an activist or civil society group) and was last mentioned here in my Oct. 7, 2011 posting), and I believe Youtie is Jan Youtie who wss mentioned in my March 29, 2012 posting about nanotechnology, economic impacts, and full life cycle assessments.