Exclusion zone water

Note: this is rather technical. 

This spring I had the pleasure of speaking briefly with a distinguished engineer, inventor, businessperson, and benefactor of science. He explained how he has recently become interested in the work of Prof. Gerald Pollack, who discovered what he calls the “4th phase of water”. The very term “4th phase of water” immediately raised an alarm bell in my head, since there are actually 19 or so known phases of water. I decided to check out what this “4th phase” was. It turns out this ‘phase’ has so far only been observed at the boundary with an odd material called Nafion, so really, it’s interfacial water with special properties, not a new phase of the liquid itself. My research focus the past three years has been understanding the microscopic details underlying the dielectric properties of water.  I am very interested in the structure and behavior of water around proteins and dissolved ions (and have read numerous papers on the subject) so naturally I am interested in Dr Pollack’s claims. Additionally, Pollack has shown that he can use the exclusion done phenomena to build a device that filters out nanospheres, and he claims his discovery can be used for desalination technology. He has not yet actually presented a functioning desalination apparatus, but he has filed a patent for the technology.
Background – pathological water science
There have been many spurious claims made about water over the years. I not referring just to the constant deluge of nonsense coming from hucksters and homeopaths who peddle ‘special’ water to cure various ailments. I am referring to research that has been pursued by highly respected scientists and published in top peer-reviewed journals like Science and Nature, but which ultimately turned out to be badly mistaken. History has shown that research having to do with water is very susceptible to what Irving Langmuir calls “pathological science“.  Two of the archetypal examples of pathological science are polywater and water memory. The case of polywater bears troubling similarities to exactly the claims Dr. Pollack has made.  Just like “EZ water”, polywater was purported to be a ‘new phase’ of water. Like EZ water, polywater only formed in special circumstances – ie. when water was condensed in tiny capillary tubes. Studying something that is confined to a tiny tube is also tricky, and in the same way, studying “EZ water” (water near a surface) is tricky. Years of painstaking research were dedicated to studying the properties of polywater. In the end it gradually became apparent that the tubes were contaminated with trace amounts of impurities, often from human sweat. In some cases, the ‘sample tubes’ contained very little water at all! The entire episode lasted about a decade before everyone admitted there was no real polywater.

I contend that the Mpbema effect, where hot water is observed to freeze faster than cold, is a modern day example of pathological water science. Invariably the experiments that found such an effect were later shown to potentially plagued by container variation, impurities, dissolved gases, and unwanted evaporation. The most carefully controlled experiment to date shows no such effect when an identical container is used (see my post on this). It was shown that “identical glass containers” are unavoidably non-identical – they have natural variation in their highest temperature nucleation site. (Brownridge, 2011)

A final example are the present day claims of the so-called autothixiotrpy of water – that containers of completely pure water will become more viscous after sitting still for a long time (months or years). The reported autothixiotropic effect is very small.

The main phenomena

an example of an exclusion zone observed in Pollack’s lab. The microspheres (right) are repelled from the Nafion sheet on the left.

Most of G. Pollack’s claims hinge on a single narrow class of experiments, where he measures how microspheres are repelled from different surfaces. In Unexpected Presence of Solute-Free Zones at Metal-Water Interfaces, for instance, he the various types of microspheres as follows:
“To quantify the size of the exclusion zone, various functionalized microspheres were used, all 1-µm diameter. These microspheres included carboxylate (2.65% solid-latex, Polysciences Inc.), polystyrene (2.65% solid-latex, Polysciences Inc.), amino (2.66% solid-latex, Polysciences Inc.), amidine (4.1% solid-latex, Invitrogen) and 488-nmexcitation fluorescent amine-modified microspheres (2% solid, yellow-green fluorescence, Invitrogen).”

The main surface that he studies in most of his work is Nafion, a proton exchange membrane developed by DuPont which is used in fuel cell technology. More specifically, it is a “sulfonated tetrafluoroethylene based fluoropolymer-copolymer”.   Nafion, and its interaction with water, has been the subject of several studiesUnfortunately, Pollack does not cite or discuss any of these studies, although I imagine he must be aware of them. Here is a list of some of relevant research that has been done on Nafion-water interaction:

  1. Quasielastic Neutron Scattering Study of Water Dynamics in Hydrated Nafion Membranes
  2. Properties of Nafion membranes under PEM water electrolysis conditions (review)
    A Computer Simulation Study of the Mesoscopic Structure of the Polyelectrolyte Membrane Nafion
  3. Molecular Simulation Study of Nafion Membrane Solvation in Water and Methanol
    An infrared study of water in perfluorosulfonate (Nafion) membranes
  4. Atomistic Simulation of Nafion Membrane. 2. Dynamics of Water Molecules and
    Hydronium Ions
  5. Structural Organization of Water-Containing Nafion: The Integral Equation Theory
    Diffusion and Interfacial Transport of Water in Nafion

Nafion can absorb a lot of water, forming a matrix of nafion and water. It is postulated that water helps the exchange of protons via Grotthuss mechanism. The structure of fully hydrated Nafion is rather complex, with numerous water domains and channels inside. The exact structure is not known (see Wikipedia). Note that Nafion may contain SO4- groups which carry negative charge. It is clearly important how these charges are arrayed on the surface!

Water’s behavior at interfaces
What do we know about the behaviour of water near interfaces? An enormous amount of research has been done on this topic, but water is complex liquid and behaves differently depending on the type of interface and the microscopic details in many cases are not fully understood. This complexity is due to the hydrogen bond network and the many different ways that water molecules can orient themselves at the interface, which alter the average structure of the H-bond network near the interface. After surveying the literature, it seems that more research has been done on hydrophobic interfaces (review here). At a very hydrophobic surface, a ‘hydrophobic gap’ is formed between the water and the interface. This gap consists of both a tiny bit of vacuum between the water and the surface and a very thin layer of lower-density water.  A 2006 study found that “the size (of the layer) is the diameter of a water molecule” and “the integrated density deficit at the interface amounts to half a monolayer of water molecules”. This result has been independently verified (see here and here) although because it is so small, it is hard to actually measure. The largest layer where the density is perturbed has an extent of about 5 Ang, at the interface with highly hydrophobic self assembled monolayers. A similar story holds for the air-water interface, which is a type of ‘hydrophobic’ interface. Water can exhibit complex behaviour at metal interfaces as well, where water molecules are known to adsorb themselves to form a surface layer. Counter-intuitively, the adsorbed water monolayer can be hydrophobic.  In any case, much less work has been done on studying water at hydrophillic interfaces.

“secondary effects”
It needs to be emphasized that there are many possible ‘secondary effects’ that can contaminate a microsphere system. Microsphere systems have been heavily studied to better understand the hydrophobic effect. Referring to research that uses plastic microspheres one scientist in the field says the following:

“these systems are notoriously plagued by secondary effects, such as bubble adsorption and cavitation effects or compositional rearrangements… Unfortunately, even if bubbles and other complications can be excluded, the very short-ranged portion of the hydrophobic between micrometer-sized surfaces can typically not be resolved experimentally because of mechanical instabilities of the measuring device. Likewise, the intricate scale dependence of the hydrophobic effect makes it nontrivial to relate the force between micrometer-sized particles to the one between molecules.”

Clearly these are temperamental systems!

Long aside: repulsive van der Waals forces? 

It occurred to me that the repulsion of the micropheres from the nafion (and metals) may be due to the repulsive van der Waals force (which in this context is also called the Casmir-Polder force). The possibility that two objects of different composition may feel a repulsive force when submerged in a liquid was first realized by Hamaker in 1937. The full theory for such forces, for arbitrary dielectric media, was worked out by Lifshitz in 1954. Lifshitz’s equations allow for a repulsive force between two objects if the dielectric susceptibility of the medium between the two plates is intermediary between the two. Recent calculations using Lifshitz theory show that the finite thickness of the slabs does not effect the repulsion between them.(Zhao, 2011)(van Zwol, 2010)

In widely-reported work in 2009, a repulsive Casmir force was measured between a gold plate and a silica sphere submerged in bromobenzene.(Munday, 2009)  This sphere-plate geometry is easier to study since one doesn’t have to worry about precisely aligning two plates.  Similar repulsion has been found in follow up work with cyclohexane and other liquids.(Meurk, 1997)(Lee, 2002) More recently, so-called intermediate-range repulsion was observed between a ZnO nanorod and a SiO2 nanorod in bromobenzene.

I managed to find a very interesting study from 1996 that measured the Casmir force between gold and PTFE submerged in several liquids, including water. Milling et al. (1996) measured the force between a gold sphere and PTFE block submerged in several liquids, including water. They state:

“For most of the polar solvents used ( water, ethanol, and dimethyl sulfoxide ) the forces between the surfaces was always attractive, albeit weakly in the case of ethanol. The only instance of repulsion between the gold and PTFE surfaces with a polar solvent was observed with dimethyl formamide…”

Although the force they measured for water was attractive, Table 2 of their study shows that theoretically a gold sphere and PTFE should repel each other in water (indicated by a negative Hamaker constant). Interestingly, the sign of the Hamaker constant predicted by theory only matches the sign found by experiment in 3/10 cases, suggesting problems with either the theory or experiment. At the end of the paper, they explain that this is likely due to incomplete knowledge about the high frequency (UV) dielectric function of the materials (the theory requires the frequency dependent dielectric function as input).

The authors also make this revealing remark:
“In some instances data collected using water as the intervening liquid showed a long-range exponential repulsion suggesting contamination of the surfaces by charge bearing groups. These may have been already present on the PTFE surfaces (21) as residual carboxylic groups from the polymerization process or other impurities, which would readily transfer to the gold surface. Clearly, van der Waals interactions between the surfaces are insufficient in describing the observed forces.”

Also, interestingly, in table 1, the dielectric constant of gold is listed as 200. I am not sure where this number comes from (metals are often considered to have an infinite dielectric constant), but I will use this number to make a point. Let’s assume the dielectric constant of the metals Dr. Pollack used is very high (at least 100). The dielectric constant of water is 78. The dielectric constant of a polystyrene microsphere is about 2.5, and it is safe to assume the others have dielectric constants between 1.5 and 3. Thus, the metal-microsphere-water system obeys the conditions necessary for Casmir Pollard repulsion.

Unfortunately, there is a fly in the ointment of this theory – retardation effects.  van der Waals forces are due to quantum mechanical charge fluctuations in atoms and molecules. For an attractive (or repulsive) force to be set up, two bodies must be able to respond to each other’s random fluctuations. If the travel time due to the speed of light becomes similar the timescale (period) of the fluctuations, then the force is weakened.  For example, for the usual der Waals force between two atoms, the force changes from falling as 1/r^7 to fall as 1/r^8.  The speed of light is slower in a liquid, which makes the situation even worse. For example, Lee and Sigmund reported measuring retardation effects at 4-5 nanometers. This is much smaller than the exclusion zone reported by Pollack (which ranges up to 100 micrometers). However, full Lifshitz theory for macroscopic bodies (ie. microspheres) seems to give a different picture. vdW forces are highly non-additive in nature and this non additive can greatly enhance the force experienced between macroscopic objects (so, for example, the force between a collection of N atoms  (microsphere) with another collection of N atoms is not just multiplied by N). In his book Intermolecular and Surface Forces, Isrealachvili notes that here is also a non-retarded zero frequency component to the vdW force. According to Isrealachvili, in many cases the progression in the vdW energy is 1/r^6 -> 1/r^7 -> 1/r^6.

In one study, the non-retarded vdW force between a microsphere and an insulating wall in water persisted up to ~200nm, about exactly the same length scale as the exclusion zone!

The repulsive van der Waals forces probably are present in the microsphere system, and they may in fact be causing the exclusion zone. There is a remaining highly speculative reason though that I believe van der Walls physics may be relevant – Pollack claims that the EZ grows when infrared radiation is shined on it. This is reminiscent of a paper I found while researching the repulsive van der Walls force. Based on the abstract of the paper, the van der Walls forces between silver nanoparticles can be enhanced by radiation, through a process involving induced dipole moments. Additionally, the argument above about retardation effects probably needs to be is modified if charge is fluctuating along the entire nano-article, as may be possible if it has conduction electrons. Overall, I am left with the impression that there are likely weird aspects of van der Waals physics / Lifshitz theory still waiting to be illuminated. Surprisingly, it was recently discovered that retardation effects can change an attractive vdW force into a repulsive one.

Debunking the quackery from Dr. Pollack
It seems that Dr. Pollack has alienated himself from the rest of the scientific community by peddling grandiose nonsense. Instead of with focusing on his discovery and getting other scientists to replicate it, Dr. Pollack has built an entire edifice of nonsense on top of it, which he documents in his book, The Fourth Phase of Water.  He discusses his ideas in a TEDx talk, another example of why TEDx is not TED. Dr. Pollack sees his ‘fourth phase’ Many of his claims are easy to refute. The first idea he has is that the hydrogens somehow lie directly between the oxygens, even though are most sophisticated quantum chemistry simulations have never shown any such behavour. Such behaviour isn’t predicted to occur in ice until extremely high pressures are reached (so called ‘superionic phase‘) The ‘phenomena’ that he attributes to EZ water are actually just mundane surface tension. Most notably, the electrically-induced water bridge (described in an earlier post) which Dr. Pollack claims is made of EZ water has been shown by researchers to have the same internal structure as regular water – implying that the water bridge is supported by enhanced surface tension.  Both molecular dynamics simulation and X-ray crystallography support this conclusion.

Pollack belongs to a group of people who think that confined water may have a special structure and special properties. Recently, the moniker ‘biological water’ has emerged to describe how cellular water may be different than normal, bulk water. It is true that confined water does exhibit different thermodynamic properties, such as reduced freezing point, and understanding how the effects of confinement change with confinement volume and geometry is an active area of research. The thermodynamic changes can largely be explained by the macroscopic phenomena of Laplace pressure of the solid-liquid boundary (detailed ref). Most of the claims about biological water have scant experimental evidence to back them up and contradict findings from computer simulation. Growing research on the hydration water around proteins shows evidence of dipolar ordering being disturbed up to a few nanometers from the protein, but structural ordering (ie, as shown in the Oxygen density PDF/RDF) is only disturbed a few angstroms from the surface.

Pollack pronounces is that when sunlight is shined on EZ water, it causes positive and negative charges to separate, and the EZ water region to grow. This seems rather dubious since water is a good conductor. In another experiment, Pollack shines light on a tube and finds flow of water.  Instead of trying to understand this experimental result through modeling the induced convection currents or by asking others to replicate it, he draws an outrageous conclusion – that the human body may absorb light to cause the blood to flow! If this was the case, mammals that live in darkness would die, along with animals with fur coats.. Most troubling, Dr. Pollack has no qualms about associating with Dr. Mercola, an anti-vaxxer and alternative medicine huckster.

The journal of which he is editor, WATER  is essentially an outlet for work on water that is too speculative or unscientific to appear in other journals. (WATER should not to be confused with the other bottom tier journal with the same name, water, which has been known to publish papers on water memory and other pseudoscience used to justify homeopathy.) Along the same lines, Pollack has helped organize a conference with an all-star lineup of the world’s top water crackpots. This is done to promote ‘speculative research’, something which I agree we need. Such conferences are dangerous though, in that they can legitimize each other’s research in an echochamber,and isolate researchers from the scientific scrutiny of the scientific community at large.

Kernel of truth 
The frustrating thing about Dr. Pollack’s research is that clearly he is observing some effect, but we can’t really say with confidence that it the type of effect he purports until it is reproduced by independent researchers!

My specific advice to Dr. Pollack (or his coworkers), is:
1. Have someone independently try to reproduce your work.
2. Cite previous work.  In one paper,  11/12 of the references are self citations! (with the remaining reference being to Einstein’s famous 1905 paper on Brownian motion). This is despite the fact that, as I mentioned, much work has already been done studying water-nafion interaction and water-microsphere systems.
3. Associating with Dr. Mercola will give you a bad reputation. Avoid him.

Update:
A very interesting and very promising theory for the exclusion zone can be found in these papers:
(1) Phenomena Associated with Gel-Water Interfaces. Analyses and Alternatives to the Long-Range Ordered water Hypothesis ( J. M. Schurr, J. Phys. Chem. B 2013, 117, 7653-7674)
— for background, see A Theory of Macromolecular Chemotaxis (J. M. Schurr et al., J. Phys. Chem. B 2013, 117, 7626-7652)
(2) Long-range Repulsion of Colloids Driven by Ion Exchange and Diffusiophoresis (D. Florea et al., Proc. Natl. Acad. Sri. USA 2014, 111, 6554-6559)

The last paper, published in PNAS, includes an independent experimental verification of the exclusion zone phenomena and neat videos. Another independent experimental verification was published here:
Exclusion Zone Dynamics Explored with Microfluidics and Optical Tweezers (I. N. Huszar, et al., Entropy 2014, 16, 4322-4337)

References

  1. Pollack GH. Chai B, Mahtani AG. Unexpected presence of solute-free zones at metal-water interfaces. Contemporary Materials, 3 1, 2012.
  2. H.C. Hamaker. The london van der waals attraction between spherical particles. Physica, 4(10):1058 – 1072, 1937.
  3. Irving Langmuir and Robert N. Hall. Pathological science. Physics Today, 42:36, 1989.
    E. M. Lifshitz. The theory of molecular attractive forces between solids. Sov. Phys. JETP, 2:73–83, 1956.
  4. Anders Meurk, Paul F. Luckham, and Lennart Bergs ̈om. Direct measurement of repulsive and attractive van der waals forces between inorganic materials. Langmuir, 13(14):3896–3899, 1997.
  5. Andrew Milling, Paul Mulvaney, and Ian Larson. Direct measurement of repulsive van der waals interactions using an atomic force microscope. Journal of Colloid and Interface Science180(2):460-465, 1996
  6. Capasso Federico Munday, J. N. and V. Adrian Parsegian. Measured long-range repulsive casimir-lifshitz forces. Nature, 457:170, 2009.
  7. P. J. van Zwol and G. Palasantzas. Repulsive casimir forces between solid materials with high-refractive-index intervening liquids. Phys. Rev. A, 81:062502, Jun 2010.
  8. Seung woo Lee and Wolfgang M. Sigmund. Afm study of repulsive van der waals forces between teflon af thin film and silica or alumina. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 204(13):43 – 50, 2002.
  9. R. Zhao, Th. Koschny, E. N. Economou, and C. M. Soukoulis. Repulsive casimir forces with finite-thickness slabs. Phys. Rev. B, 83:075108, Feb 2011.

13 Comments

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13 Responses to Exclusion zone water

  1. James McGinn

    I think you were mostly fair to Pollack in this piece. I had a chance to talk to him for about an hour on the phone last spring. I explained my discovery regarding polarity neutralization through hydrogen bonding. He didn’t seem to grasp it. But he at least seemed to be trying. He wa . . . .
    Delete this

  2. James McGinn

    I think you were mostly fair to Pollack in this piece. I had a chance to talk to him for about an hour on the phone last spring. I explained my discovery regarding polarity neutralization through hydrogen bonding. He didn’t seem to grasp it. But he at least seemed to be trying. He was also open to my assertion regarding the role of water in the atmosphere being completely misunderstood and mischaracterized by meteorology. (Some of his own speculations extend into the atmosphere, most of which I find poorly considered.)

    I think exclusion zone is overwrought. To me it doesn’t seem that different from reverse osmosis. But he, apparently, envisions it being many layers deep. And then there is all the speculations that you mention, sunlight, etc. I agree with your assessment. I also agree, as you indicate, that he definitely saw something. But, at best, I think we could say that he discovered another of the anomalies of H2O.

    Pollacks shortcomings notwithstanding there are also some considerable shortcomings associated with you “insiders” to the study of water. Being an outsider I think I recognize Pollack’s frustration with how you insiders are so completely lost in your own narrative.

    Specifically, insiders, like yourself, appear to be oblivious to the fact that your inability to resolve the many anomalies of H2O is indicative of the very real possibility that your model of water carries fundamental flaws. We might even say that you are being seduced by your own model–you are allowing the model to dictate what is valid or invalid. You think you understand what is happening at the molecular level, but actually it is your own model, not reality, that is providing you this confidence. You are trying to fit the round peg of water into the square peg of your model and you are failing. Again, your failure is made evident by the fact that you can’t explain anomalies and instead waste your resources trying to dismiss them or minimize them. (You have zero chance of effectively dismissing Mpemba, and it is one of many anomalies.)

    I know exactly where the flaws are in the conventional model:
    You are myopically focussed on electronegativity differences as being the cause of polarity and you discount, or dismiss, the importance of asymmetry.
    You don’t realize that hydrogen bonds have the same effect on the electron cloud as to covalent bonds
    Due to #1 and #2 you don’t realize that polarity is neutralized by the completion of bonds (restoring symmetry), producing a pendulumic relationship that conserves energy (thus explaining high heat capacity of H2O). Polarity is reactivated with bond distance.
    Your model of ice and the freezing process is based on idealized notions that have no basis in reality
    You missed a gigantic clue that is staring you right in the face that your model of freezing is mistaken. This is copied from my paper:
    Although the process underlying the origins of supercooled water—what we might describe as the antithesis of the freezing process—seemed to not have been adequately explained by the conventional model this was not the main reason my attention was drawn to it. Rather, it was the fact that the situational circumstances associated with its origins seemed to directly contradict what is predicted by the conventional model. Specifically, since the freezing process associated with the conventional model indicates an increase in the polar alignment of H2O molecules during the transition from liquid to ice it seems reasonable that one would predict chaotic or agitated conditions as the underlying root cause, but exactly the opposite is the case. Supercooled water is associated with situational factors in which water is cooled very gradually under placid, calm conditions.3 To me this indicated that the underlying mechanism involves the comprehensiveness of symmetrically coordinated bonds being locked in, forming a threshold that inhibits the breaking of bonds without which, in accordance with my hypothetical thinking, polarity remains dormant, preventing the formation of ice. And so, lastly, I hope to distinguish this new model by demonstrating that it engenders an elegant explanation as to why the conditional factors underlying supercooled water involve gradual cooling and placid, calm conditions.
    Generally: You are so obsessed with what you think you know and dismissive of what you can’t explain. You need to take the opposite approach. You should be dismissive of what you think you know and obsessed with what you can’t explain.

    In short: Your model has lead you by the nose. You aren’t using the anomalies as evidence that would bring you to look for a new model, instead you are spending your time trying to dismiss the significance of the anomalies.

    Daniel, you may fool yourself into thinking you can explain away the evidence of Mpemba. But you won’t be able to do anything but dismiss the evidence associated with non-Newtonian fluids.

    Here is my response to a comment on Physics Stack Exchange that I think is applicable here:
    Water is unique. My paper describes why. I am not surprised by your inability to dispute it. In so doing you reveal the ineptitude of conventional theory. But that isn’t necessary in that conventional theory has thus far–and despite no shortage of resources–failed miserably to reconcile the numerous anomalies of H2O, preferring, instead, to arrogantly dismiss them, hiding behind the perceived validity of their model instead of addressing arguments directly and, thereby, exposing the shortcomings of conventional misthinking.

    The following involves quotes from your article that I am responding to directly:

    Dan Elton: My research focus the past three years has been understanding the microscopic details underlying the dielectric properties of water.
    Jim McGinn: The inverse relationship with respect to polarity and distance solves the problem.
    Dan Elton: I am referring to research that has been pursued by highly respected scientists
    which ultimately turned out to be badly mistaken.
    Jim McGinn: The fact that it took so long to reveal it as mistaken indicates shortcomings of the conventional model.
    Dan Elton: History has shown that research having to do with water is very susceptible to what Irving Langmuir calls “pathological science“.
    Jim McGinn: It is susceptible because your model contains fundamental flaws.
    Dan Elton: polywater was purported to be a ‘new phase’ of water.
    Jim McGinn: Overwrought, as with EZ water, but there is something to this that conventional theory can’t explain.
    Dan Elton: water was condensed in tiny capillary tubes. Studying something that is confined to a tiny tube is also tricky, and in the same way, studying “EZ water” (water near a surface) is tricky. Jim McGinn: The mechanism that allows water to be pulled up in a chain or polymer (as in trees) is not well explained by conventional theory. My theory describes the molecular mechanism thereof. Conventional theory has, thus far, failed.
    Dan Elton: Mpbema effect, where hot water is observed to freeze faster than cold, is a modern day example of pathological water science.
    Jim McGinn: The evidence associate with Mpemba is subtle but indisputable. It can’t be resolved by the conventional model–revealing fundamental shortcomings of conventional model.
    Dan Elton: What do we know about the behaviour of water near interfaces? An enormous amount of research has been done on this topic, but water is complex liquid and behaves differently depending on the type of interface and the microscopic details in many cases are not fully understood.
    Jim McGinn:
    Dan Elton: Counter-intuitively, the adsorbed water monolayer can be hydrophobic.
    Jim McGinn: I’ve known about this. This has significant implications on my theories of atmospheric flow. Specifically, I theorize tha the inner surface (surface tension on “steroids”) of jetsteam vortices (and tornado vortices) has this property, thus allowing them to act as conduits of moist air without the moist air interfering with the integrity of the surface of the plasma-like structure of the vortice.
    Dan Elton: Long aside: repulsive van der Waals forces?
    Jim McGinn: When all else fails conventional theorists resort to van der Waals. It is used as an excuse rather than an explanation. It is overused.
    Dan Elton: The ‘phenomena’ that he attributes to EZ water are actually just mundane surface tension.
    Jim McGinn: Yes! You hit the nail on the head with this comment. But conventional theory has, thus far, failed to account for surface tension. My theory provides the missing ingredient.
    Dan Elton: This is done to promote ‘speculative research’, something which I agree we need.
    Kernel of truth
    Jim McGinn: We have mountains of evidence. Your theory is flawed. More evidence isn’t going to fix flawed theory. My paper provides the missing ingredient to fix the flawed theory.
    Dan Elton: The frustrating thing about Dr. Pollack’s research is that clearly he is observing some effect, but we can’t really say with confidence that it the type of effect he purports until it is reproduced by independent researchers!
    Jim McGinn: Excellent! This shows you have not completely closed your minds.
    Dan Elton: My specific advice to Dr. Pollack (or his coworkers), is:
    Jim McGinn: I suggest reading these two conversations I had with Soper and Saykally:
    https://groups.google.com/d/msg/sci.physics/8KHDL5XTD3U/bMN_XgiVEwAJ

    https://groups.google.com/d/msg/sci.physics/catCSHRs2Ns/S70bizqKEwAJ
    So, Dan, don’t waste your time telling me that my thinking is inconsistent with your model. Soper and Saykally tried that and I threw it back in their faces. Your model fails because you guys failed to comprehend simple concepts like importance of symmetry to polarity. And you allowed yourselvs to be seduced by the idealized model of ice and freezing. And you are way to comfortable with the fact that your model fails to explain so many of the anomalies causing you to waste time trying to dismiss them when these are the best clues you have to point you toward the only chance you will ever have of refuting the model that is the plank in your eye.

  3. delton137

    Hi James,

    Well you say “You are myopically focussed on electronegativity differences as being the cause of polarity..” I think you mean electrical charge?

    Then you say, “You don’t realize that hydrogen bonds have the same effect on the electron cloud as to covalent bonds.” — well, hydrogen bonds have been heavily studied and its understood there is a clear distinction between hydrogen bonds and covalent bonds. H-bonds are largely due to short-range dipole-dipole interaction, but they also have a covalent character (there can be charge transfer). This is standard, well established chemistry, and the IUPAC definition of the H-bond reflects this.

    The conversation with Soper is interesting. I haven’t read the entire exchange but I agree with his main point – hydrogen bonds increase the dipole moment (polarity) of the hydrogen bond donator.

    That is why the dipole moment increases from the gas phase value of 1.85 D to the value in the liquid of 2.7-3 D. In ice, where each molecule has 4 strong H-bonds, the dipole moment is I believe around 3.2 D.

    The liquid phase value of ~3D is well established at this point, for instance see:
    http://scitation.aip.org/content/aip/journal/jcp/117/11/10.1063/1.1501122

    Another way to see this basic fact would be to look at some of vast literature on clusters. (which are obviously important in atmospheric phsyics)
    Some of the simulations and experiments give dipole moments, I believe. You will see the dipole moments increase as the number of hydrogen bonds increase.

    There is an anticorrelation between the OH bond strength and Hydrogen bond strength. The presence of a hydrogen bond weakens the OH bond.

    This is why hydrogen bonding causes a red-shifting of the frequencies. The effect is very subtle and complicated by nuclear quantum effects, though. In D2O, where the effects of quantum delocatlization are smaller, the covalent OD bond is stronger than an OH bond and the hydrogen bonds are weaker. This causes an anomolous expansion of D2O ice and water, which another grad student in my group research extensively : https://mvfsgroup.wordpress.com/2012/04/02/first-paper-of-betul-pamuk-is-accepted-to-phys-rev-lett/

    If you are interested here are some more references on quantum delocalization on hydrogen bonding :
    http://www.chem.ucl.ac.uk/ice/docs/PNAS_2011_XLi.pdf
    http://arxiv.org/pdf/1401.3792v3.pdf

    As a final point, I wasn’t promoting or using any particular ‘model’ in this blog post. I was criticizing Pollack’s work on very general grounds, and it follows a historical trend of bad research on water, and you haven’t really pointed out anything specifically that invalidates my criticisms.

  4. James McGinn

    DE: I think you mean electrical charge?

    JM: No, I was referring to the electronegativity differences of the atoms that participate in a covalent bond. For example, H-C, in methane and H-O in water. See this:
    http://www.chemteam.info/Bonding/Electroneg-Bond-Polarity.html
    This is very important. You have to understand this or you will not understand polarity. I provide more quantitative explanation in my paper.

    DE: Then you say, “You don’t realize that hydrogen bonds have the same effect on the electron cloud as to covalent bonds.” — well, . . .

    JM: My assertion was that your education has has shortchanged you into thinking that polarity is all about electronegativity differences when actually that is only part of what causes a molecule to be polar. Electronegativity one of two factors that underlie polarity, the other is symmetry. And, most importantly, although electronegativity differences do not change symmetry actually does, with completion of hydrogen bonds in H2O. (If this concept isn’t clear I recommend sitting on it until it is.

    JM: My assertion is that hydrogen bonds fulfill symmetry, neutralizing polarity. You have no dispute with this assertion. All you can do is ignore it, because your model give you false confidence that this can be ignored. And that is the real problem. You’ve been educated to think you understand something that you really don’t. Your instructors have glossed over the details of polarity giving you to false impression that the details are not important.

    DE: “its understood there is a clear distinction between hydrogen bonds and covalent bonds.

    JM: That is obvious. (If there wasn’t a distinction we wouldn’t be having this conversation.) You missed the significance of my statement. And the reason you missed the significance, I can only assume, is because you don’t understand the how the lopsidedness of the electron cloud on the oxygen side of the H2O molecule is what causes polarity and how the completion of a hydrogen bond pushed the electron cloud back to the center of the oxygen molecule, neutralizing polarity. (Alan Soper couldn’t grasp this concept either.)

    JM: So, I suggest rereading my statement with this new understanding in mind. A hydrogen bond has the same effect ON THE ELECTRON CLOUD that a covalent bond has.

    JM: A little overview:
    Carbon has the same steric number as oxygen and, therefore, they both share the same template for the positions of their respective electron pairs, a tetrahedron. Methane is not a polar molecule because its four covalent bonds push the electron cloud to the center of the carbon atom. H2O is a polar molecule because it only has two covalent bonds. However, when hydrogen bonds are formed they have the same effect ON THE ELECTRON CLOUD that a covalent bond has. Thusly, when hydrogen bonds are formed polarity is, effectively, neutralized–the electron cloud is pushed to the center of the oxygen atom. (The implicaitions of this strange inverse relationship between bonds strength and bond completion is what undelies all of H2O’s anomalies.) This is the thing you (you insiders) are not grasping. And it all comes back around to the fact that your model gives you the arrogant belief that you can gloss over these details.

    JM: You have to fully understand polarity first. And you aren’t there yet. Only after you fully understand it will you be in position to realize how completion of hydrogen bonds neautralizes polarity. And only then can you start to understand the ensuing implications thereof. So, hand in there. It is going to take a while for you to understand all of this. Read my paper.

    DE: “H-bonds are largely due to short-range dipole-dipole interaction,”

    JM: This fact isn’t disputed. The dispute is how do we characterize the force or forces that maintain this distance. My model does that elegantly. Your model relies on phantom forces that over-extend the influence of the Pauli Exclusion principle. (See my conversation with Alan Soper for details.)

    DE: but they also have a covalent character (there can be charge transfer).

    JM: Yes. Pauling discovered this (initially). It dovetails with my model.

    DE: “This is standard, well established chemistry, and the IUPAC definition of the H-bond reflects this.”

    JM: Who cares. You see, this is the kind of arrogance your education has left you with. You barely understand polarity and you are trying to tell me my model is wrong because of a definition that you look up in a book. Definitions don’t define reality. Definitions attempt to capture reality and represent it, but they often are put on paper by people that don’t yet have a full grasp of the facts. If you rely on definitions to make your argument you are limiting your argument to the intelligence of the person that created the definition. And these definitions were often created by somebody who had limited understanding.

    DE: The conversation with Soper is interesting. I haven’t read the entire exchange but I agree with his main point – hydrogen bonds increase the dipole moment (polarity) of the hydrogen bond donator.

    JM: It is an absurd assertion that he was unable to support except to assert the existence of a phantom force. He is wrong to rely on phantom forces to make his argument, and you are wrong to blindly follow.

    DE: That is why . . .

    JM: When you present an argument you can’t just skip over the cause and start talking about the result. As I mentioned to Alan, you are presenting a “skyhook” argument.

    DE: the dipole moment increases from the gas phase value of 1.85 D to the value in the liquid of 2.7-3 D.

    JM: Alan discussed distances, not dipole moment. So, you are not making a coherent argument. The pieces of the puzzle of your model don’t fit. As you know, the measurment are highly interpreted. Make sure your theory makes sense first before you start pretending to correctly interpret the evidence.

    JM: Once again, all I’m seeing here is arrogance of partial understanding. You barely understand polarity, you model doesn’t make sense, and it has left you with the false confidence that you undertand what you do not.

    DE: In ice, where each molecule has 4 strong H-bonds, the dipole moment is I believe around 3.2 D.

    JM: Ice does not involve 4 strong H bonds. Again, this is your model giving you false confidence. This has never been confirmed. It’s a belief based on models, not on evidence.

    JM: I will try to look at some of the other things you posted here, but I don’t see the relevance to my post.

    DE: As a final point, I wasn’t promoting or using any particular ‘model’ in this blog post.

    JM: I’m saying your whole paradigm, your whole collective belief system (not just you) have allowed the model to dictate conclusions. You did it here, for example, when you stated: “”H-bonds are largely due to short-range dipole-dipole interaction,”
    “This is standard, well established chemistry, and the IUPAC definition of the H-bond reflects this.”
    “hydrogen bonds increase the dipole moment (polarity) of the hydrogen bond donator.”
    “That is why the dipole moment increases from the gas phase value of 1.85 D to the value in the liquid of 2.7-3 D. In ice, where each molecule has 4 strong H-bonds, the dipole moment is I believe around 3.2 D.”

    JM: My point is that you state these things with the confidence as if they have been empirically proven, and they haven’t. Most of these are conjecture or half conjectures based on interpreted evidence that itself was interpreted through the rose colored lenses of a paradigm that “everybody knows is true.” So what you really have is a belief system that gives you false confidence that you understand more than you actually do. And I am seeing this in every person associated with your paradigm.

    JM: Stop myopically focussing on the things you think you know. They will only give you false confidence that you can ignore what your model fails to explain.

    JM: Remember, at the time, everybody thought physics was in its finally chapter. Electromagnetic anomalies were just a small problem that most thought could be easily ignored. Einstien didn’t dismiss the anomalies. He tried to explain them.

    DE: I was criticizing Pollack’s work on very general grounds, and it follows a historical trend of bad research on water, and you haven’t really pointed out anything specifically that invalidates my criticisms.

    JM: I agree with your criticism. (I thought this was clear.) I’m just saying that the reason the door is open to the “bad research” is because the current models have failed to explain the anomalies. Your model is flawed. And the reason you can’t see it is because you are allowing the model to lead you by the nose. You are myopically focusing on what your model does explain and dismissing what it fails to explain. I gave you a perfect example. Your model will fail to explain non-newtonian fluids. My model explains it elegantly, effortlessly.

    JM: My model explains everything your model explains and it explains the things you mode fails to explain.

    Thanks for the response.

    • delton137

      Well, you haven’t given me any reason to doubt the common knowledge.

      You have presented zero evidence to the contrary, only assertions that I am blinded by my education. Well, my eyes are wide open and I am giving you full chance to present evidence for your assertion, either experimental or on theoretical grounds.

      I know what electronegativity is, although I admit as a physicist I’m not used to thinking of these problems in terms of electronegativity. Obviously charge moves from lower to higher. But that is all really besides the point. There are many facts that are established experimentally and corroborated with well-validated simulation methodologies, among them being that dipole moment of water increases from 1.8 to 3 going from gas to liquid.

      Now much of this increase explained on general grounds as being due to what’s called a ‘reaction field’ set up by the background dielectric media. The molecule polarizes its surrounding medium, which creates an electric field which further enhances the molecule’s polarization. This effect is enhanced by H-bonding, which increases dipole-dipole correlations. Kirkwood wrote a paper about this effect long ago
      http://scitation.aip.org/content/aip/journal/jcp/7/10/10.1063/1.1750343

      Kirkwood assumed the hydrogen bonds are tetrahedrally coordinated, and on the basis of this calculated the enhanced dipole moment and the dielectric constant. His calcualtion, while only considers the first shell, but he got within the right order of magnitude.

      Also, note the first sentence in the abstract to this paper:
      http://www.cchem.berkeley.edu/rjsgrp/publications/papers/1997/187_gregory_1997.pdf

      At some point I will look at your longer writeup when I have time. You are right that many facts are often taken for granted which are in fact hard to prove. Measuring the charge distributions and dipole moments in the liquid phase for instance is tricky, they have to be carefully inferred from various experiments (for instance x-ray scattering, where there is a debate about how to do it) and the experiments have to be corroborated with theory and computation.

  5. James McGinn

    Well, you haven’t given me any reason to doubt the common knowledge.

    I shouldn’t need to. You should already be doubting it. You should be very cognizant of the anomalies. You should be skeptical of authoritative claims. You should be making 100% sure that you fully understand H2O polarity (and h bonding) because that is what really distinguishes H2O from other similar molecules. And, frankly, I don’t think you are there yet. You aren’t yet fully conversant.

    My model explains all of the anomalies (potentially) your model does not (despite no shortage of resources and researchers). My model has no need for “skyhook” explanations, your model has many skyhooks. My model is based on an explicit understanding of what is happening to the electron cloud on the oxygen molecule, your model is based on consensus. authority, skyhook conclusions, and “experiments” that are not immune from confirmation bias. That is what I am seeing. These are your word: “hydrogen bonds have been heavily studied and its understood there is a clear distinction between hydrogen bonds and covalent bonds. H-bonds are largely due to short-range dipole-dipole interaction, but they also have a covalent character (there can be charge transfer). This is standard, well established chemistry, and the IUPAC definition of the H-bond reflects this.”

    You have presented zero evidence to the contrary, only assertions that I am blinded by my education.

    Predictably, you failed to support most of your arguments with substance.

    Well, my eyes are wide open and I am giving you full chance to present evidence for your assertion, either experimental or on theoretical grounds.

    I’ve already given you some. Your model predicts the initial conditions underlying supercooled water are the opposite of what they actually are. And your model fails to explain nonnewtonian fluids and mpemba effect. It also failed to predict that warmer water had more ice, which your own phonon experiments confirmed.

    But the biggest of all is the fact that you were unable to find anything explicitly erroneous about my notion of polarity neutralization by hydrogen bonding. Your only argument was to start telling me all the assumptions underlying your model–same thing Alan Soper did. (The strangest thing of all was that the things you were disputing my model with were the things that are most immeasurable of all. Alan’s explanation got really absurd in that he started talking about Pauli Exclusion principle, which only applies to atoms actually touching.)

    I know what electronegativity is, although I admit as a physicist I’m not used to thinking of these problems in terms of electronegativity. Obviously charge moves from lower to higher.

    The next step is to get symmetry straight in your mind. Because a molecule can only be a dipole if it’s electronegativity differences are distributed asymmetrically. The next step after that is to understand how symmetry is restored through hydrogen bonding. Then the fun begins. Then anomalies start becoming resolved–easily. (The easiest one of all to resolve is H2O’s high heat capacity.)

    But that is all really besides the point.

    Surreal. How can that be, “besided the point.”

    There are many facts that are established experimentally and corroborated with well-validated simulation methodologies, among them being that dipole moment of water increases from 1.8 to 3 going from gas to liquid.

    So, you made measurements that confirmed what you model predicted. Your approach is susceptible to confirmation bias. How do you know that my model wouldn’t make the same predictions? Or even some other model that neither of us know about? The truth is you don’t know.

    The best experiments involve two competing, well-defined hypotheses with specific predictions that decisively distinguish between them. If you don’t do that then, almost always, your results are going to give you false confidence that your model has been confirmed.

    Now much of this increase explained on general grounds as being due to what’s called a ‘reaction field’ set up by the background dielectric media.

    Yikes. Reaction field? Dielectric media? For hydrogen bonding between water molecule? Either you just changed the subject or what you are stating here sounds incredibly contrived. Are you, maybe, talking about something that is interfacial?

    The molecule polarizes its surrounding medium, which creates an electric field which further enhances the molecule’s polarization.

    Sorry, but this sounds contrived. It almost sounds spiritualistic. Why would these magical abilities only exist for water molecules? Does this actually explain anything or does it just add another layer of complexity to provide you with more false confidence. Sorry, but that is what I’m seeing.

    This effect is enhanced by H-bonding, which increases dipole-dipole correlations. Kirkwood wrote a paper about this effect long ago
    http://scitation.aip.org/content/aip/journal/jcp/7/10/10.1063/1.1750343

    Kirkwood sounds like a very imaginative fellow. But why would these magical abilities only exist for water? Do you see the problem with this, Daniel?

    Kirkwood assumed the hydrogen bonds are tetrahedrally coordinated, and on the basis of this calculated the enhanced dipole moment and the dielectric constant. His calcualtion, while only considers the first shell, but he got within the right order of magnitude.

    Do you find that convincing? I don’t. I find it contrived and desperate. And I’m not saying that just to be contrarian. And I’m also not saying this out of ignorance of the issue: there definitely is space between water molecules. And there definitely is a need for an explanation of what force or process maintains that space. (BTW, the space is not constant, it varies greatly.)

    Also, note the first sentence in the abstract to this paper:
    http://www.cchem.berkeley.edu/rjsgrp/publications/papers/1997/187_gregory_1997.pdf

    At some point I will look at your longer writeup when I have time. You are right that many facts are often taken for granted which are in fact hard to prove. Measuring the charge distributions and dipole moments in the liquid phase for instance is tricky,

    It is subject to interpretation bias based on initial assumption. Specifically, if what I am saying about there being an inverse relationship between distance and bond strength then the interpreted significance of the “two peaks” has been transposed. (Anders Nilsson)

    they have to be carefully inferred from various experiments (for instance x-ray scattering, where there is a debate about how to do it) and the experiments have to be corroborated with theory and computation.

    Yes, and the big argument started with Nilsson et all, in 2004.

  6. James McGinn

    Also, note the first sentence in the abstract to this paper:
    http://www.cchem.berkeley.edu/rjsgrp/publications/papers/1997/187_gregory_1997.pdf

    I read it. Not impressed. Nothing here gave me the slightest confidence that they actually isolated a monomer and measured it. (The only way one could knowingly isolate a monomer involves raising its temperature over 100 degrees C, and then how do you measure it?) Instead I’m seeing the phrase Ab Initro calculations, which is just a deceptive way of concealing the fact that you/they are making calculation based on assumptions (“first principles”). Also, as you probably already know, I consider Saykally a hack.

    Because of that last comment, you might want to consider not publishing this. (Or you can edit it out.)

    No offense, Daniel, but I’m still a bit perplexed as to how you got as far as you did in this discipline and not be fully conversant in something as fundamental as electronegativity. This criticism isn’t directed at you so much as it is at the education system that allowed you to get this far without this understanding. I think you students are inundated with so much blatant, “well-considered” nonsense (Kirkwood) that you are overwhelmed. It just gives you false confidence that, “we got it all figured out.”

    Do get a better understanding of the factors that dictate the tetrahron on C, N, O, and Fl. Then build upon that to better understand the significance of symmetry/asymmetry and its effect on the electron cloud to determine polarity. After that the neutralization of H2O through hydrogen bonding will be an easy concept to grasp.

    Stop obsessing over what your model does explain and start obsessing over what it cannot. If I was you I wouldn’t even bother with Mpemba. You will, most likely, only fool yourself into believing you can dismiss it. Go right to Non-newtonian fluids. You will not be able to resolve that with your model. And that will force you to be more skeptical of your model, something you and nobody in this discipline (except me) is inclined to do.

    Good Luck

    James McGinn
    Solving Tornadoes

  7. James McGinn

    DE: The conversation with Soper is interesting. I haven’t read the entire exchange but I agree with his main point – hydrogen bonds increase the dipole moment (polarity) of the hydrogen bond donator. That is why the dipole moment increases from the gas phase value of 1.85 D to the value in the liquid of 2.7-3 D. In ice, where each molecule has 4 strong H-bonds, the dipole moment is I believe around 3.2 D.

    JM: The dipole moment is increasing because H bonds are being broken in ice. You (conventional theory) has transposed the significance of the data to arrive at a false positive interpretation of your data.

  8. James McGinn

    “That is why the dipole moment increases from the gas phase value of 1.85 D”

    How do you know what they say is “gas” is actually gas and not water vapor which is actually liquid (with a lot of surface and, therefore, a lot of surface tension)?

    It’s a common error to assume that vaporous H2O is gaseous when it is actually not.

  9. J. Michael Schurr

    In order to understand Pollack’s exclusion zones, one must first determine whether they are equilibrium phenomena, as Pollack believes, or instead are merely long-lived non-equilibrium transients involving small-ion gradients wherein the microspheres move, as now appears to be the case. Macromolecular motions induced by small-ion or small molecule gradients are called molecular chemotaxis or cross-diffusion in general, and diffusiophoresis in those special cases where charged macromolecules in a small-ion gradient are driven entirely by electrostatic and hydrodynamic forces with no contribution from forces of shorter range, such as chemical binding forces. Relevant references are:
    (1) A Theory of Macromolecular Chemotaxis (J. M. Schurr et al., J. Phys. Chem. B 2013, 117, 7626-7652); see supplementary information for critique of conventional diffusiophoresis theory.
    (2) Phenomena Associated with Gel-Water Interfaces. Analyses and Alternatives to the Long-Range Ordered water Hypothesis ( J. M. Schurr, J. Phys. Chem. B 2013, 117, 7653-7674)
    (3) Exclusion Zone Dynamics Explored with Microfluidics and Optical Tweezers (I. N. Huszar, et al., Entropy 2014, 16, 4322-4337)
    (4) Long-range Repulsion of Colloids Driven by Ion Exchange and Diffusiophoresis (D. Florea et al., Proc. Natl. Acad. Sri. USA 2014, 111, 6554-6559). Any contribution from acid or base binding by the colloid is omitted from this treatment, but the argument for an origin of the exclusion zones in long-lived non-equilibrium small ion gradients is compelling.

    • delton137

      Just found and approved your comment today – it got sent to spam by mistake..

      Very interesting! I read the abstracts to the papers, and while I don’t understand the details yet, it sounds like a big step towards understanding the exclusion zone phenomena. I also looked at Pollack’s response. The pictures Pollack has published several times where he uses the pH indicator definitely show a gradient in acidity. At some point I’ll dig into your papers more. I wonder what implications this type of phenomena may have for cellular biology. The Entropy paper is also encouraging as an independent verification of the phenomena. I would imagine other experimental groups would be willing to study this, especially after the publication of your JPCB and work in PNAS. The experiments seem extremely simple to set up, but I suppose these type of systems can be temperamental and tricky to study.

      • delton137

        also, clearly your theory should be testable by monitoring things over time. When I first saw Pollack’s pictures I definitely wondered how a pH gradient could be sustained in such a system – obviously the gradients can’t be sustained indefinitely.

        I have added the papers you provided to the end of the article.

  10. J. Michael Schurr

    The phenomenon of macromolecular chemotaxis must have had a significant role in evolution, since it allows any organism with carboxylate, phosphate, or other charged groups on its surface to migrate away from its metabolic waste products, provided only that such waste products differ in pH from the surrounding solution, and are excreted in an asymmetric manner so as to maintain a fixed orientation of the pH gradient surrounding the cell as it moves. Macromolecular chemotaxis is also capable of inducing or assisting other relevant motions, such as (initially) oxygenated red blood cells moving through capillary beds in muscles toward higher concentrations of of H+ and HCO3- ions, both of which are bound by the formerly oxygenated hemoglobin inside such cells, and the deoxygenated red blood cells bearing bound H+ and HCO3- ions through the capillary bed in the lungs toward the regions of higher concentration of O2, which is bound by the formerly deoxygenated hemoglobin as it simultaneously dissociates its H+ and HCO3- ( which in turn combine to form H2CO3 that is dehydrated by carbonic anhydrase to yield CO2, which is then outgassed in the lung.
    The experiments are indeed “temperamental”. When a solution bearing a pH gradient is placed in contact with a glass surface, or other ionized surface, the solution will be convected along the surface by the same kind of chemotactic traction toward the acidic end of the gradient that is responsible for the motion of ionized microspheres through the same gradient bearing solution. One needs to work with a cell that has charge-free surfaces. We tried to do that by working with a polymethymethacrylate (PMMA) “cell”, but were thwarted in three of our five tries (each with a different “channel”). We suspect that our problem was unexpected convection caused by ionizable silanol groups formed by oxygen plasma treatment of the PMMA surface during the fabrication process. Such groups were supposed to be subsequently buried by surface reconstruction to form an entirely hydrophobic surface, but very (three times out of five) were not.

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