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lyotropic, a. Physical Chem.|laɪəˈtrɒpɪk, -ˈtrəʊpɪk|
[f. lyotrope a. + -ic: see -tropic.]
1. Associated with the change of internal pressure of a solution from that of the solvent which is caused by the solute. lyotropic series, a series in which ions are arranged in order of their lytropic effects, esp. their ability to cause precipitation of a lyophilic sol.
1924W. A. Patrick in H. S. Taylor Treat Physical Chem. II. xx. 1285 Those properties of solutions or liquids that are in causal relation to the forces of molecular attraction are termed lyotropic. We thus have two great groups of properties of solutions, the colligative, and the lyotropic. 1925G. Barger tr. Freundlich's Elem. Colloid Chem. 27 The characteristic series of cations and anions so obtained..are called the lyotropic series. 1926H. S. Hatfield tr. Freundlich's Colloid & Capillary Chem. 49 We can therefore distinghish from the group of properties which are comprehended in the van't Hoff theory a second independent group, which are due to the change of the internal pressure by the solute. These properties will be described as lyotropic; the influence of the solute upon the surface tension, the compressibility, the solubility of difficultly soluble substances, and others will be called lyotropic influences. 1937Chem. Rev. XX. 170 The numbers obtained in the case of salting-out experiments with lyophilic colloids play an important part in other lyotropic phenomena. Ibid. 179 Since the heat of hydration of ions depends on the electric field which surrounds them, the lyotropic effects are beyond doubt caused by the different electric field strengths of the ions. 1956Bacteriol. Rev. XX. 51/2 Attempts have been made to correlate the toxicity of various salts to the lyotropic..series. 1970Biochemistry IX. 2802/1 We have adopted an approach to the elucidation of lyotropic mechanism in which the effects of related perturbants on a standard collagen-buffer system have been compared.
2. Of a mesophase: having its phase transitions readily effected by a change of concentration. Also applied to the mesomorphism exhibited by such a mesophase.
1933Trans. Faraday Soc. XXIX. 1008 (heading) Lyotropic mesomorphism. 1966Molecular Crystals II. 55 Lyotropic systems are also thermotropic and it is the co⁓operative action of the temperature and of the solvent which enables them to pass successively from the solid crystalline state to the liquid crystalline state and to the isotropic liquid or dissolved state. 1969Analytical Chem. Nov. 26A/3 Liquid crystals are divided into two major groups. One of these is identified as thermotropic, indicating that the class is prepared by heating... Lyotropic liquid crystals constitute the second major group and are prepared by mixing two or more components. In two-component systems involving water the second component is generally an amphiphile. Lyotropic systems can be large in number and varied in composition. 1974P. G. de Gennes Physics Liquid Crystals i. 5 For all the systems listed in this section, the transitions are induced most easily by changing the concentration of rods rather than the temperature; for this reason they are commonly called lyotropic. Ibid. 6 Depending on which..conditions hold, amphiphilic compounds may be lyotropic or thermotropic. |