softmatter:Nematic Order Parameter

From NSDL Materials Digital Library Soft Matter Wiki

One can measure the degree of order in a rod like system by using the following order parameter [1,2]:

where theta is the angle with respect to the director (average direction of the rods) in the system. Typically values of the order parameter [1,2]:

• Crystal: S~1
• Disordered liquids: S<0.3
• Liquid crystals: S~0.3-0.9

References

• [1] The Structure and Rheology of Complex Fluids
• [2] Polymers and Liquid Crystals Virtual Text Book