Experimental relationship between surface and bulk rotational viscosities in nematic liquid crystals

Abstract

Systematic measurements of the surface viscosity of several nematic liquid crystals in contact with a polymercaptan layer show that the latter scales like the bulk rotational viscosity . This result is interpreted in the framework of a ‘delocalized model’ for the surface viscosity.

Keywords:

• nematic liquid crystals
• sliding anchoring
• rotational surface viscosity
• rotational bulk viscosity
• polymercaptan layer

Acknowlegements

The authors are grateful to A. Pretrosyan for lending them his rubbing machine to prepare the planar samples and to A. Dequidt for fruitful comments. One of the authors (V.P.-N.) thanks Ecole Normale Supérieure de Lyon for scientific hospitality and acknowledges support from CNRS.