A phase diagram of smectogen-non-smectogen binary mixture: A photon transmission study


Yildiz S. , Serhatli I. , PEKCAN O., BERKER A., OBEK H.

INTERNATIONAL JOURNAL OF MODERN PHYSICS B, vol.16, no.26, pp.3959-3970, 2002 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 16 Issue: 26
  • Publication Date: 2002
  • Doi Number: 10.1142/s0217979202013122
  • Title of Journal : INTERNATIONAL JOURNAL OF MODERN PHYSICS B
  • Page Numbers: pp.3959-3970

Abstract

The ultraviolet/visible photon transmission technique was applied to study the phase diagram of a mixture of 4-ethoxy-4'-(6-vinyloxyhexyloxyl) azobenzene (VE), a smectogen, and 4-hexoxy-3'-methyl-4-(6-acryloyloxyhexyloxy) azobenzene (AH), which by itself exhibits no liquid crystalline behavior. It has been found that the N-Sm-A phase line terminates at either a tricritical point at about X-VE = 0.9, where X-VE is the weight percentage of VE in the binary mixture, or at least at a tricritical region 0.9 < X-VE < 1 within the experimental resolution. For X-VE = 1 the nematic phase region is not large enough to drive the transition second-order. It is found that the value of the critical exponent beta for X-VE = 0.9 is consistent with the tricritical value.