Diffusivity Maximum in a Reentrant Nematic Phase

International Journal of Molecular Sciences

Tillmann Stieger¹  Marco G. Mazza¹ 

[1] Stranski-Lab for Physical and Theoretical Chemistry, Berlin Institute of Technology, 135 June 17th Street, Berlin 10623, Germany; E-Mails:

关键词: reentrant phase;    nematic;    dynamics;    diffusion;   

DOI  :  10.3390/ijms13067854

来源: mdpi

【 摘 要 】

We report molecular dynamics simulations of confined liquid crystals using the Gay–Berne–Kihara model. Upon isobaric cooling, the standard sequence of isotropic–nematic–smectic A phase transitions is found. Upon further cooling a reentrant nematic phase occurs. We investigate the temperature dependence of the self-diffusion coefficient of the fluid in the nematic, smectic and reentrant nematic phases. We find a maximum in diffusivity upon isobaric cooling. Diffusion increases dramatically in the reentrant phase due to the high orientational molecular order. As the temperature is lowered, the diffusion coefficient follows an Arrhenius behavior. The activation energy of the reentrant phase is found in reasonable agreement with the reported experimental data. We discuss how repulsive interactions may be the underlying mechanism that could explain the occurrence of reentrant nematic behavior for polar and non-polar molecules.

【 授权许可】

CC BY   
© 2012 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.