The exclusion zone is a large stratum (typically on the order of a few microns to a millimeter) observed in pure liquid water, from which particles of other materials in suspension are repelled. It is observed next to the surface of solid materials, e.g. the walls of the container in which the liquid water is held, or solid specimens immersed in it, and also at the water/air interface. Several independent research groups have reported observations of the exclusion zone next to hydrophilic surfaces.[1][2][3][4] Some research groups have reported the observation of the exclusion zone next to metal surfaces.[5][6] The Exclusion zone has been observed using different techniques, e.g. birefringence, neutron radiography, nuclear magnetic resonance, and others,[4] and it has potentially high importance in biology, and in engineering applications such as filtration and microfluidics.
Historical background
editThe first observations of a different behavior of water molecules, close to the walls of its container, date back to late 1960s and early 1970s, when Drost-Hansen, upon reviewing many experimental articles, came to the conclusion that interfacial water shows structural difference.[7][8]
In 1986 Deryagin and his colleagues observed an exclusion zone next to the walls of cells.[9]
In 2006 the group of Gerald Pollack reported their observation of what they called an exclusion zone. They observed that the particles of colloidal and molecular solutes suspended in aqueous solution are profoundly and extensively excluded from the vicinity of various hydrophilic surfaces.[1] The exclusion zone has been observed and characterized by several independent groups since those early observations.[10][11][4]
Theoretical models
editSince the early observations, several theoretical models have been proposed, to explain the experimental observation of the exclusion zone.
Mechanical model: Change in geometrical structure
editSome researchers suggest that the exclusion zone is due to a change in the geometrical structure of water, induced by the surface of the hydrophilic (or metal) solid water's structure.[1][12] In this model, the water in the exclusion zone has a structure of hexagonal sheets, where the hydrogen atoms are positioned between oxygen atoms. Moreover, hydrogen atoms bond to the oxygens atoms lying in the layer above and below so that in total each hydrogen forms three bonds. This structure can be considered as an intermediate between ice and water. However, the hexagonal sheet hypothesis does not account for all aspects of the exclusion zone, and it is not supported by the majority of physicists.
Quantum Electrodynamical model: quantum confinement
editAnother calculation performed describes the molecules of the exclusion zone using Quantum Mechanics and Quantum Electrodynamics. In this model the liquid bulk water is in a gaseous state. Then, above a certain density threshold and below a specific critical temperature, those molecules go to another quantum state, with lower energy. In this lower energy, coherent state, the cloud of electrons oscillate between two quantum states: a ground state, and an excited state where one electron per molecule is almost free (the binding energy is about 0.5 eV). In this coherent state the quantum superposition has a component with coefficient 0.9 of the ground state, and a component with 0.1 of the excited state. The electrons in this quantum state oscillate between the ground state and the excited state with a certain frequency, and this oscillation creates an electromagnetic field, which is confined within the super-molecular structure, so that no radiation is observed. The molecules of the structure, together with the confined electromagnetic field, constitute in this model the exclusion zone.[13]
References
edit- ^ a b c Zheng, Jian-ming; Chin, Wei-Chun; Khijniak, Eugene; Pollack, Gerald H. (2006). "Surfaces and interfacial water: Evidence that hydrophilic surfaces have long-range impact". Advances in Colloid and Interface Science. 127 (1): 19–27. doi:10.1016/j.cis.2006.07.002. PMID 16952332.
- ^ Chen, Chi-Shuo; Chung, Wei-Ju; Hsu, Ian C.; Wu, Chien-Ming; Chin, Wei-Chun (2011). "Force field measurements within the exclusion zone of water". Journal of Biological Physics. 38 (1): 113–120. doi:10.1007/s10867-011-9237-5. PMC 3285724. PMID 23277674.
- ^ Bischof, Marco; Del Giudice, Emilio (2013). "Communication and the Emergence and of Collective and Behavior in and Living Organisms: A Quantum and Approach". Molecular Biology International. 2013: 987549. doi:10.1155/2013/987549. PMC 3833029. PMID 24288611.
- ^ a b c Elton, Daniel C.; Spencer, Peter D.; Riches, James D.; Williams, Elizabeth D. (2020-07-17). "Exclusion Zone Phenomena in Water - A Critical Review of Experimental Findings and Theories". International Journal of Molecular Sciences. 21 (14): 5041. doi:10.3390/ijms21145041. PMC 7404113. PMID 32708867.
- ^ Pedroza, Luana S.; Poissier, Adrien; Fernández-Serra, M.-V. (2015). "Local order of liquid water at metallic electrode surfaces". The Journal of Chemical Physics. 142 (3): 034706. Bibcode:2015JChPh.142c4706P. doi:10.1063/1.4905493. PMID 25612724. Archived from the original on 2022-03-19. Retrieved 2022-03-19.
- ^ Chai, B; Mahtani, AG; Pollack, GH (2012). "Unexpected presence of solute-free zones at metal-water interfaces". Contemporary Materials. 3 (1): 1–12. doi:10.7251/COM1201001C. PMC 3692373. PMID 23807904.
- ^ Drost-Hansen, Walter (1969). "Structure of water near solid interfaces". Industrial & Engineering Chemistry. 61 (11): 10–47. doi:10.1021/ie50719a005.
- ^ Drost-Hansen, Walter (1973). "Phase transitions in biological systems: manifestations of cooperative processes in vicinal water". Annals of the Lyceum of Natural History of New York. 204 (1): 100–112. Bibcode:1973NYASA.204..100D. doi:10.1111/j.1749-6632.1973.tb30773.x. PMID 4513148. S2CID 35243683.
- ^ Deryagin, BV; Golovanov, MV (1986). "Electromagnetic nature of forces of repulsion forming aureoles around cells". Colloid Journal of the USSR. 48 (2): 209–211.
- ^ Chen, Chi-Shuo; Chung, Wei-Ju; Hsu, Ian C; Wu, Chien-Ming; Chin, Wei-Chun (2012). "Force field measurements within the exclusion zone of water". Journal of Biological Physics. 38 (1): 113–120. doi:10.1007/s10867-011-9237-5. PMC 3285724. PMID 23277674.
- ^ Huszár, István N; Mártonfalvi, Zsolt; Laki, András József; Iván, Kristóf; Kellermayer, Miklós (2014). "Exclusion-zone dynamics explored with microfluidics and optical tweezers". Entropy. 16 (8): 4322–4337. Bibcode:2014Entrp..16.4322H. doi:10.3390/e16084322.
- ^ Oehr, Klaus; LeMay, Paul (2014). "The Case for Tetrahedral Oxy-subhydride (TOSH) Structures in the Exclusion Zones of Anchored Polar Solvents Including Water". Entropy. 16 (11): 5712–5720. Bibcode:2014Entrp..16.5712O. doi:10.3390/e16115712.
- ^ V. Elia, R. Germano; C. Hison, E. Del Giudice (2013). "Oxhydroelectric Effect in bi-distilled water". Key Engineering Materials. 543: 455–459. doi:10.4028/www.scientific.net/KEM.543.455. S2CID 94391774. Archived from the original on 2022-03-19. Retrieved 2022-03-19.