Enhancement by polydispersity of the biaxial nematic phase in a mixture of hard rods and plates.
The phase diagram of a polydisperse mixture of uniaxial rodlike and platelike hard parallelepipeds is determined for aspect ratios kappa=5 and 15. All particles have equal volume, and polydispersity is introduced in a highly symmetric way. The corresponding binary mixture is known to have a biaxial phase for kappa=15, but to be unstable against demixing into two uniaxial nematics for kappa=5. The phase diagram for kappa=15 is qualitatively similar to that of the binary mixture, regardless of the amount of polydispersity, while for kappa=5 a sufficient amount of polydispersity stabilizes the biaxial phase. This provides clues for designing an experiment to observe this long searched biaxial phase.
Martínez-Ratón
Yuri
Y
Grupo Interdisciplinar de Sistemas Complicados (GISC), Departamento de Matemáticas, Unversidad Carlos III de Madrid, Avenida de la Universidad, 30, E-28911, Leganés, Madrid, Spain. yuri@math.uc3m.es
Cuesta
José A
JA