Summary
The mesomorphic or “liquid crystalline” neat and middle phases encountered in aqueous systems of soaps and synthetic detergents differ considerably in plasticity. Nevertheless, in fundamental phase studies or the examination of commercial products and processes, identification of these two phases has hitherto been uncertain, particularly when they are mixed with each other or with other phases; even under the polarizing microscope, their identification has not been positive since, by the classical criteria for identifying mesomorphic phases, both are “smectic.”
The present work reveals additional criteria by which the two phases may be satisfactorily distinguished. In the first place, there are non-geometric textures exhibited by middle but not by neat. Conversely, there are planar textures exhibited by neat but not by middle. Furthermore there are important systematic differences even among the focal conic textures upon which the smectic nature of the two phases has previously been predicated.
While the microscopic method now makes possible the identification of phase mixtures, it serves also as a rapid method even where one-phase compositions are concerned.
This study is primarily descriptive in its present state of development, but the existence of systematic microscopic differences between these two nominally smectic phases, coupled with their well-known and pronounced difference in consistency, suggests a fundamental structural distinction between them.
Much of the present subject-matter applies also to such materials as certain wetting agents and dyes, as well as phosphatides and certain other biological substances.
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References
Bernal, J. D., and Crowfoot, D., Trans. Faraday Soc.,29, 1042–3 (1933).
Bragg, W. H., Trans. Faraday Soc.,29, 1056–60 (1933).
Bragg, W. H., Proc. Roy. Inst. Gt. Brit.,28, 57–93 (1934); see Plates I, II.
Bragg, W. H.,ibid., Plates I and II, Figures 6, 7 and 8.
Cameron, J.,Soaps and Candles, p. 102, Blakiston, Phila. (1888).
de Bretteville, A. Jr., and McBain, J. W., J. Chem. Phys.,11, 426–9 (1943).
Dervichian, D. G., Trans. Faraday Soc.,42B, 180–7 (1946), espec. 183.
Doscher, T. M., and Vold, R. D., J. Coll. Sci.,1, 299–312 (1946).
Doscher, T. M., and Vold, R. D., J. Phys. & Colloid Chem.,52, 97–109 (1948).
Ferguson, R. H.,et al., unpublished work in this laboratory, beginning 1932.
Ferguson, R. H., and Richardson, A. S., Ind. Eng. Chem.,24, 1329–36 (1932).
Friedel, G., Ann. de physique,18, 300–304 (1922); see Plates 4 and 5 at end of volume. (More briefly in Ref. 16.)
Friedel, G.,ibid., 304–327; see Plates 6–10, 14, 16 at end of volume. Friedel terms a region based on a single ellipse and its corresponding hyperbola a “focal domain.”
Friedel, G.,ibid., 324–7; also Plates 11 and 18.
Friedel, G.,ibid., 328 ff.
Friedel, G., in Alexander’sColloid Chemistry, vol. I, pp. 107–8, Chem. Catalog Co., N. Y. (1926).
Friedel, G.,ibid.. Planar areas with sheets not parallel to the surface of the preparation, being derived ordinarily from sizeable single crystals, are rare in soaps.
Friedel, G., Z. Krist.,79, 9 (1931).
Hartshorne, N. H., and Stuart, A.,Crystals and the Polarizing Microscope, 2nd ed., Arnold, London (1950), chap. IX, espec. pp. 331–41.
Hermann, C., Z. Krist.,79, 186–221 (1931).
Hyde, A. J., Nature,170, 234 (1952).
Lascaray, L., in Hefter-Schönfeld,Fette u. Fettprodukte, vol. IV, pp. 122, 125–7, 179 ff., Springer, Vienna (1939).
Lascaray, L.,ibid., pp. 122, 125.
Lascaray, L.,ibid., pp. 125, 181.
Lawrence, A. S. C., J. Roy. Microscop. Soc.58, 30–48 (1938); see Figure 3.
Lehmann, O.,Flüssige Kristalle, Engelmann, Leipzig (1904): Photogr. 6 of Plate 1, Photogr. 1 of Plate 2.
Lehmann, O., ibid., Photogr. 6 and 7 of Plate 9.
Lehmann, O., ibid., Plates 3–5.
Lehman, O., Z physik., Chem.,4, 462–72 (1889).
Lehmann, O., Wied. Ann.,56, 771–88 (1895).
Lewkowitsch, J.,Chem. Technol. ... Oils, Fats and Waxes, 5th ed., vol. III, Macmillan, London (1915), p. 304.
Maclennan, K., J. Soc. Chem. Ind.,42, 393T-401T (1923), Figures 6 and 8; while the specific compositions of these are not given, the captions and accompanying text indicate that they must be neat soaps.
Maclennan, K.,ibid., Figures 20, 21.
McBain J. W., Nature,115,805–7 (1925); 2.5 Nw (37.5%) potassium laurate (in water) 45°C. Original photomicrograph of composition later shown to be middle soap (42).
McBain, J. W., Proc. Roy. Inst. Gt. Brit.,1925, 579–84, Figure 2: 3 Nw (42%) potassium laurate.
McBain, J. W., in Alexander’sColloid Chemistry, vol. I, pp. 137–64, Chem. Catalog Co., N. Y. (1926).
McBain, J. W., J. Chem. Ed.,6, 2115–27 (1929), Figure 21: reprinting of photo from Ref. 34; Figure 20: 3 Nw (42%) potassium laurate.
McBain, J. W.,ibid., Figure 22: 2.5 Nw (37.5%) potassium laurate, anisotropic liquid phase separating from isotropic melt at unspecified temperature.
McBain, J. W.,ibid., Figure 12.
McBain, J. W., and Elford, W. J., J. Chem. Soc.,1926, 421–38.
McBain, J. W., and Elford, W. J.,ibid., Photographs I and III: 9 Nw (74%) and 25 Nw (89%) potassium oleate in water. These two photographs, along with a statement that 4 Nw (56%) potassium oleate separates from isotropic liquid at 240°C. as “batonnets,” appear to constitute the total original evidence for the smectic nature of neat soap.
McBain, J. W., and Field, M. C., J. Phys. Chem.,30, 1545–63 (1926).
McBain, J. W., and Langdon, G. M., J. Chem. Soc.,1925, 852–70.
McBain, J. W., Lazarus, L. H., and Pitter, A. V., Z. physik. Chem.,A147, 87–117 (1930).
McBain, J. W., and Lee, W. W., Oil & Soap,20, 17–25 (1943).
McBain, J. W., Vold, M. J., and Porter, J. L., Ind. Eng. Chem.,33, 1049–55 (1941).
McBain, J. W., Vold, R. D., and Frick, M., J. Phys. Chem.,44, 1013–24 (1940).
McBain, J. W., Vold, R. D., and Vold, M. J., J. Am. Chem. Soc.,60, 1866–9 (1938).
McBain, J. W., and Watts, O., J. Rheol.,3, 437–60 (1932). Figure 2: reprinting of photo from Ref. 34.
Nordsieck, H., Rosevear, F. B., and Ferguson, R. H., J. Chem. Phys.,16, 175–80 (1948).
Rinne, F., Trans. Faraday Soc.,29, 1016–32 (1933); Figure 2 of Plate I.
Rosevear, F. B., Am. Mineral.,32, 693–4 (1947).
Vold, M. J., J. Am. Chem. Soc.,63, 1427–32 (1941).
Vold, R. D., J. Phys. Chem.,43, 1213–31 (1939).
Vold, R. D.,ibid., a) Figure 8: 36% sodium oleate, 80°C.; b) Figure 9: 36% sodium oleate, 115°C.
Vold, R. D.,ibid., Figure 11: 56% sodium oleate at 90°C.
Vold, R. D.,ibid., Figures 10, 12, 13, 14.
Vold, R. D., Soap Sanit. Chemicals,16, 31–37 (1940).
Vold, R. D., and Ferguson, R. H., J. Am. Chem. Soc.,60, 6066–76 (1938).
Vold, R. D., Reivere, R., and McBain, J. W., J. Am. Chem. Soc.,63, 1293–6 (1941).
Vold, R. D., Rosevear, F. B., and Ferguson, R. H., Oil & Soap,16, 48–51 (1939).
Vold, R. D., and Vold, M. J., J. Am. Chem. Soc.,61, 808–16 (1939).
Vold, R. D., and Vold, M. J., in Alexander’sColloid Chemistry, vol. V, pp. 266–80, espec. Figure 5, Reinhold Publ. Corp., N. Y. (1944).
Vold, R. D., and Vold, M. J., J. Phys. & Colloid Chem.,52, 1424–44 (1948).
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Presented before the Colloid Division, American Chemical Society, Chicago, Ill., Sept. 7, 1953; portions presented before the Crystallographic Soc. of America, Annapolis, Md., March 21, 1947. For abstract see Ref. 52.
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Rosevear, F.B. The microscopy of the liquid crystalline neat and middle phases of soaps and synthetic detergents. J Am Oil Chem Soc 31, 628–639 (1954). https://doi.org/10.1007/BF02545595
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DOI: https://doi.org/10.1007/BF02545595