Phase transitions in polymesomorphic compounds

Il Nuovo Cimento D - Tập 7 - Trang 421-436 - 1986
R. Caciuffo1, S. Melone1, G. Torquati1, V. G. K. M. Pisipati2, N. V. S. Rao2
1Dipartimento di Scienze dei Materiali e della Terra, Facoltà di Ingegneria dell'Università, Ancona, Italia
2Faculty of Physical Sciences, Nagarjuna University, Nagarjuna Nagar, India

Tóm tắt

The results of a X-ray diffraction study, performed on N(p-n-pentyloxy benzylidene)p′-n-octylaniline (50.8) and N(p-n-pentyloxy benzylidene)p′-n-decylaniline (50.10) are presented. The investigated compounds exhibit smecticB, smecticA and nematic phases in between solid and isotropic liquid phases. In addition, after a thermal cycle the 50.8 compound exhibits a smecticG phase at room temperature. The interlayer and the in-plane intermolecular distances were obtained as functions of temperature through all the mesophases. A phase coexistence has been observed during the solid to smecticB and the smecticB to smecticA phase transitions of the 50.8 compound. The nematic to smecticA phase transitions are found to be of second order for both compounds. Pretransitional effects due to cybotactic-cluster formation in the nematic region are observed.

Tài liệu tham khảo

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Thông tin
Thông tin xuất bản

Il Nuovo Cimento D

Tập 7

421-436

Thông tin tác giả