Advertisement

On the polymorphism of the smectic A phases of highly polar compounds

  • N. V. Madhusudana
Crystallography
  • 24 Downloads

Abstract

The smectic A phase is characterized by a layered arrangement of rod-like molecules, with the average orientation of the molecules normal to the layers and a liquid-like organization within the layers. When the molecules have a strongly polar end group (like-C≡N, -NO2 etc.,), neighbouring molecules prefer an antiparallel orientation. This results in a bilayer structure, with a layer spacing much larger than the molecular length. In many compounds, the structure of the bilayer is sensitive to temperature (or pressure). This results in some interesting phenomena: (a) reentrant phases, as for example, the appearance of a nematic phase below the temperature range of existence of the A phase; (b) a number of polymorphic forms of smectic A; and (c) an ‘induced smectic A’ phase when the compounds with the highly polar terminal groups are mixed with weakly polar compounds even when neither compound by itself exhibits the A phase. This article gives a brief summary of recent results on all these aspects.

Keywords

smectic A polymorphism reentrant phases bilayer smectics induced smectic phases 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Ais-Nielsen J 1981 inSymmetries and broken symmetries in condensed matter physics, (ed.) N Boccara (Paris: Idset) p. 107Google Scholar
  2. Anderson A C, Reese W and Wheatley J C 1963Phys. Rev. 130 1644CrossRefGoogle Scholar
  3. Benguigui L and Hardouin F 1981J. Phys. Lett. (Paris) 42 L-111Google Scholar
  4. Berker A N and Walker J S 1981Phys. Rev. Lett. 41 1469CrossRefGoogle Scholar
  5. Billard J 1979 inLiquid Crystals, Proc. Int. Conf. Bangalore, (ed.) S Chandrasekhar (London: Heyden) p. 155Google Scholar
  6. Born M 1916Sitz. d. Phys. Math. 25 614Google Scholar
  7. Brownsey G J and Leadbetter A J 1980Phys. Rev. Lett. 44 1608CrossRefGoogle Scholar
  8. Chandrasekhar S 1977Liquid Crystals (Cambridge: University Press)Google Scholar
  9. Chandrasekhar S and Madhusudana N V 1978 inProgress in Liquid Physics (ed.) C A Croxton (Chichester: Wiley) Ch. 14Google Scholar
  10. Chandrasekhar S, Suresh K A and Rao K V 1979 inLiquid Crystals, Proc. Int. Conf. Bangalore, (ed.) S Chandrasekhar (London: Heyden) p. 131Google Scholar
  11. Cladis P E 1975Phys. Rev. Lett. 35 48CrossRefGoogle Scholar
  12. Cladis P E 1979 inLiquid Crystals, Proc. Int. Conf. Bangalore, (ed.) S Chandrasekhar (London: Heyden) p. 105Google Scholar
  13. Cladis P E, Bogardus R K and Aadsen 1978Phys. Rev. A18 2292Google Scholar
  14. Cladis P E, Bogardus R K, Daniels W B and Taylor G N 1977Phys. Rev. Lett. 39 720CrossRefGoogle Scholar
  15. Clark N A 1979J. Phys. (Paris) 40 C3–345Google Scholar
  16. Dave J S, Patel K L and Vasanth K L 1966Indian J. Chem. 4 505Google Scholar
  17. de Gennes P G 1972Solid State Commun. 10 753CrossRefGoogle Scholar
  18. de Gennes P G 1975The physics of liquid crystals (Oxford: Clarendon Press)Google Scholar
  19. de Jeu W H 1982Solid State Commun. 41 529CrossRefGoogle Scholar
  20. Engelen B, Heppke G, Hopf R and Schneider F 1979Mol. Cryst. Liquid Cryst. Lett. 49 193CrossRefGoogle Scholar
  21. Guillon D and Skoulios 1983Mol. Cryst. Liquid Cryst. Lett. 92 1CrossRefGoogle Scholar
  22. Hardouin F and Levelut A M 1980J. Phys. (Paris) 41 41Google Scholar
  23. Hardouin F, Sigaud G, Achard M F and Gasparoux H 1979Phys. Lett. A71 347Google Scholar
  24. Heppke G and Schneider F 1979 inLiquid Crystals, Proc. Int. Conf. Bangalore, (ed.) S Chandrasekhar (London: Heyden) p. 147Google Scholar
  25. Hida K 1981J. Phys. Soc. Jpn 50 3869CrossRefGoogle Scholar
  26. Klug D D and Whalley E 1979J. Chem. Phys. 71 1874CrossRefGoogle Scholar
  27. Landau L D and Lifshitz E M 1959Statistical physics (London: Pergamon)Google Scholar
  28. Leadbetter A J, Richardson R M and Colling C N 1975J. Phys. (Paris) 36 C1–37Google Scholar
  29. Leadbetter A J, Frost J C, Gaughan J P, Gray G W and Mosley A 1979J. Phys. (Paris) 36 C1–37Google Scholar
  30. Levelut A M, Tarento R J, Hardouin F, Achard M F and Sigaud G 1981Phys. Rev. A24 2180Google Scholar
  31. Longa L and de Jeu N H 1982Phys. Rev. A26 1632Google Scholar
  32. Lyden J E and Coakley C J 1975J. Phys. (Paris) 36 C1–45Google Scholar
  33. Madhusudana N V and Chandrasekhar S 1973 Int. Liquid Crystals Conf., Bangalore,Pramana Suppl.1 57Google Scholar
  34. Madhusudana N V, Sadashiva B K and Moodithaya K P L 1979Curr. Sci. 48 613Google Scholar
  35. Madhusudana N V, Savithramma K L and Chandrasekhar S 1977Pramana 8 22CrossRefGoogle Scholar
  36. Madhusudana N V and Srikanta B S 1982 9th Int. Liquid Crystal Conf.,Mol. Cryst. Liq. Cryst. (in press)Google Scholar
  37. Madhusudana N V, Srikanta B S and Subramanya Raj Urs 1982aMol. Cryst. Liq. Cryst. Lett. 82 25CrossRefGoogle Scholar
  38. Madhusudana N V, Srikanta B S and Subramanya Raj Urs 1982bMol. Cryst. Liq. Cryst. Lett. 82 317CrossRefGoogle Scholar
  39. Madhusudana N V, Srikanta B S and Subramanya Raj Urs 1982c 9th Int. Liquid Crystal Conf., Bangalore,Mol. Cryst. Liq. Cryst. (in press)Google Scholar
  40. Maier W and Saupe A 1959Z. Naturforsch. 14a 882Google Scholar
  41. McMillan W L 1971Phys. Rev. A4 1238Google Scholar
  42. Meyer R B and Lubensky T C 1976Phys. Rév. A14 2307Google Scholar
  43. Moodithaya K P L and Madhusudana N V 1979 inLiquid Crystals, Proc. Int. Conf. (ed.) S Chandrasekhar (London: Heyden) p. 297Google Scholar
  44. Park J W, Bak C S and Labes M M 1975J. Am. Chem. Soc. 97 4398CrossRefGoogle Scholar
  45. Peierls R E 1934Helv. Phys. Acta Suppl. 7 81Google Scholar
  46. Pelzl G, Demus D and Sackmann H 1968Z. Phys. Chem. (Leipzig) 238 22Google Scholar
  47. Pelzl G, Botger U and Demus D 1981Cryst. Res. Tech. K16 67Google Scholar
  48. Pershan P S and Prost J 1979J. Phys. Lett. (Paris) 40 L-27Google Scholar
  49. Prost J 1980 inLiquid crystals of one- and two-dimensional order, (eds) W Helfrich and G Heppke (Berlin: Springer-Verlag) p. 125Google Scholar
  50. Prost J 1981 inSymmetries and broken symmetries in condensed matter physics (ed.) N Boccara (Paris: Idset) p. 159Google Scholar
  51. Ratna B R, Shashidhar R and Rao K V 1979 inLiquid Crystals, Proc. Int. Conf. Bangalore, (ed.) S Chandrasekhar, (London: Heyden) p. 135Google Scholar
  52. Riblot G and Winzer K 1971Solid State Commun. 9 1663CrossRefGoogle Scholar
  53. Schaetzing R and Litster J D 1979 inAdvances in liquid crystals (ed.) G H Brown (New York: Academic Press) p. 147Google Scholar
  54. Schneider F and Sharma N K. 1981Z. Naturforsch. 36a 1086Google Scholar
  55. Sharma N K, Pelzl G, Demus D and Weissflog W 1980Z. Phys. Chem. (Leipzig) 261 579Google Scholar
  56. Shashidhar R 1983Proc. Indian Acad. Sci. (Chem. Sci.) 92Google Scholar
  57. Sigaud G, Hardouin F, Achard M F and Gasparoux H 1979J. Phys. (Paris) 40 C3–356CrossRefGoogle Scholar
  58. Srikanta B S and Madhusudana N V 1982 9th Int. Liquid Crystal Conf., Bangalore,Mol. Cryst. Liq. Cryst. (in press)Google Scholar
  59. Subramanya Raj Urs M and Sadashiva B K 1982Mol. Cryst. Liqu. Cryst. Lett. 72 227CrossRefGoogle Scholar
  60. Tinh N H 1983Mol. Cryst. Liq. Cryst. 91 285CrossRefGoogle Scholar
  61. Tinh N H, Hardouin F and Destrade C 1982aJ. Phys. (Paris) 43 1127Google Scholar
  62. Tinh N H, Hardouin F, Destrade C and Levelut A M 1982bJ. Phys. Lett. (Paris) 43 L-33Google Scholar

Copyright information

© Printed in India 1983

Authors and Affiliations

  • N. V. Madhusudana
    • 1
  1. 1.Raman Research InstituteBangalore

Personalised recommendations