Action of a weak static magnetic field on a family of nematic liquid crystals as starting point for the study of this effect on biological membranes

Abstract

Long-range ordered molecular systems, such as many biological intracellular membranes, are related to problems of human health and can be affected by physical effects such as electric and magnetic. To study the effect of low-intensity static magnetic fields (<40 mT), four alkylcyanobiphenyls (5CB, 6CB, 7CB and 8CB) were chosen as suitable model compounds. These liquid crystals contain two benzene rings, known to be susceptible to magnetic fields, but they also have an aliphatic chain of variable length that is affected by magnetic field, as observed on lecithin crystals. The object of this work was to examine their behaviour over the whole birefringent mesophase through changes in the refractive index of the extraordinary beam (ne), because the behaviour of the extraordinary refractive index (ne) as a function of the field intensity (B) and temperature (K) could be recorded over the whole mesophases. Three-dimensional plots (ne vs B vs K) indicated a distinct behaviour in the ne depending on the chain length of the alkyl substituent. This suggests that this procedure could be useful to examine the effect of weak static magnetic fields on liquid crystalline like molecular systems, especially those of biological interest.