This issue of Dilutions Digest addresses research into the effects of different physical stresses on the properties of water. Listed below are some of the most conspicuous, in our view, studies that have recently been published in this area.
Changing the constants
Scientists from the University of Siena have published findings from their relaxation time experiments with water exposed to different physical stresses . The paper appeared in the International Journal of Design & Nature and Ecodynamics in 2020. A total of 174 NMR proton relaxation time experiments were performed by the authors over a period of 20 years in several universities. T1 and T2 (the spin-lattice relaxation time and the spin-spin relaxation time, respectively) were measured in different samples of water: distilled, homeopathic, spring water and water treated with electromagnetic fields. All samples were deoxygenated and particular care was devoted to avoiding paramagnetic impurities. According to classical magnetic resonance literature, for water, T1 and T2 are equal and each is 3.6 s. The authors obtained surprising results: in all the water samples, T1 was two or three times greater than T2. The results can be explained in terms of recent physical theories such as coherence domains, quantum electrodynamics (QED), thermodynamics of irreversible processes (TIP) and Pollack’s water exclusion zone (EZ). These results were related to the formation of a supramolecular structure of water in experimental samples.
Comparison of Т1 and Т2 for water samples treated with an electromagnetic field
According to the authors, water relaxation parameters may vary with the form and surface properties of materials that it interfaces.
The paper published in PHYSICS OF WAVE PHENOMENA in 2021 has studied the effects of serial dilutions and mechanical shaking on the conductivity of water samples . Electrical characteristics of water samples subjected to mechanical shaking and subsequent dilution by initial (unperturbed) water were investigated in the frequency region 10 kHz to 10 MHz. In all cases, the frequency increment of the permittivity was absent, and temporal variations in the permittivity were below 0.1%. Conductivity of all water samples showed nonmonotonic dependence on the number of centesimal dilution iterations. Graphic patterns underwent time evolution for several days while retaining correlation between them. Patterns obtained with the samples prepared on different days were different. Two simultaneously prepared sets of samples showed high correlation. Statistical characteristics of patterns of settled water samples differed from those of freshly prepared purified water. The hypomagnetic field caused the average variance of pattern characteristics to decrease with time.
The paper in the International Journal of Molecular Sciences  reports on long-lived luminescence that was found to occur in the blue region in deionized water saturated with atmospheric gases following mechanical shaking. Luminescence intensity decreased exponentially after the cessation of stress. During vigorous mechanical shaking, gas bubbles were observed in solution, and the liquid–gas interface area increased noticeably.
The effect of mechanical stress (30 Hz, amplitude of 5 mm, for 5 min) on intrinsic water luminescence (A) and gaseous phase distribution (B). The photograph was taken shortly after the mechanical treatment.
At the same time, the concentration of molecular oxygen decreased, which could not be attributed to increases in water temperature with exposure to mechanical stress. However, deaerated water rapidly became saturated with gases following mechanical stress. The authors suggest that the standard approach that recommends that cell culture media should be mixed after they are removed from the fridge in order to allow saturation with oxygen might be incorrect. They showed that gases that existed in water in the form of individual molecules as well as nanobubbles, and mechanical stress did not influence the number or size of the latter. While gas nanobubbles were absent in freshly prepared deaerated water, they appeared following exposure to mechanical stress. Furtherоre, there was an apparent equilibrium shift towards the decomposition of carbonic acid to water and carbon dioxide in mechanically purified gas-saturated water. Along with this, pH of water tended to increase once it was mechanically treated. It was shown that reactive oxygen species (ROS) form in gas-saturated water under mechanical stress (30 Hz, amplitude of 5 mm). The relative generation rate of hydrogen peroxide and of the hydroxyl radical was 1 nM/min and 0.5 nM/min, respectively. The rate of ROS generation was found to increase in proportion to f2 with an increase in the frequency of mechanical action (f). The major pathways for hydrogen peroxide generation might be associated with the formation of singlet oxygen and its further reduction, and the formation of hydrogen peroxide as a result of hydroxyl radical recombination is named by the authors as the alternative way.
WaTuSo. ‘Tunable’ solvent
In 2020, Chemical Society Reviews published a paper on the use of water as a “tunable” solvent . Although water is the sustainable solvent of excellence, its high polarity limits the solubility of non-polar compounds. According to the authors of the paper, when confined in hydrophobic pores, water shows altered hydrogen bonding structure and changes in related properties such as dielectric constant and solvation power. It has not been explored so far whether this special state of confined water may be made usable in chemical processes. The authors report that confining water in hydrophobic pores enables the use of water as a so-called “tunable” solvent (referred to by the authors as WaTuSo).
WaTuSo (Water Tunable Solvent) concept implemented in a pressure swing cycle: a heterogeneous mixture of non-polar compounds and water intrudes the nanoporous host material where the mixture becomes a single phase suitable for storage or catalysis. Depressurization causes extrusion; water regains its bulk properties and non-polar compounds segregate again.
Following exposure to pressure forces, heterogeneous mixtures of poorly soluble molecules and water permeate into hydrophobic nanopores of a host material where the lowered polarity of water enhances the dissolution of nonpolar solutes. Decompression occurring after the reaction causes expulsion of the solution from the pores and spontaneous demixing of reaction products because water returns to its normal polar state. Temporarily enhanced dissolution of hydrophobic compounds as observed during confinement is expected to be advantageous to chemical reaction and molecular storage. Nano-confined water could become an alternative to compression for storing CH4 and H2 gas, and offer new opportunities for green chemistry such as aqueous phase hydrogenation reactions, which benefit from enhanced hydrogen solubility. Unprecedented control in time and space over H2O solvation properties in a WaTuSo system will broadly expand the potential of using new technologies.
Investigations of the properties of water, and in particular the effects of different physical stresses on water, have recently become an important area of research for scientists worldwide. However paradoxical it may sound, water is one of the most common, yet one of the least explored substances on Earth. New surprising findings are presented each year by scientists specialized in this area. Noteworthy, technologies relying on the use of water properties are typically environmentally friendly, which perfectly fits in with modern views of global sustainable development. Importantly, in addition to enlarging the theoretical basis, water properties experiments are acquiring increasingly practical applications.
1. Tiezzi E., Catalucci M., Marchettini N. THE SUPRAMOLECULAR STRUCTURE OF WATER: NMR STUDIES. International Journal of Design & Nature and Ecodynamics, 2020
2. Lobyshev V.I. Evolution of High-Frequency Conductivity of Pure Water Samples Subjected to Mechanical Action: Effect of a Hypomagnetic Field. Physics of Wave Phenomena, 2021
3. Gudkov S.V., Penkov N.V., Baimler I.V., Lyakhov G.A., Pustovoy V.I., Simakin A.V., Sarimov R.M., Scherbakov I.A. Effect of Mechanical Shaking on the Physicochemical Properties of Aqueous Solutions. Int J Mol Sci. 2020
4. Chem. Soc. Rev., 2020,49, 2557-2569