Static Light-Scattering By Aqueous-Solutions Of Rodlike Fd-Virus Particles

Static light scattering measurements are reported on aqueous solutions of rodlike fd-virus (length L = 880 nm, molecular weight 16.4 × 10 6 g/mol) below and above the overlap concentration c ∗ = 1 particle/length 3 . In solutions of very low ionic strength a liquidlike structure with a significant first intensity maximum of the elastically scattered light is observed due to the electrostatic interaction of the charged rods. The scattering vector of the first static structure factor maximum scales with concentration as c 1/3 below c ∗ and as c 1/2 above. In comparison to results of spherical particle solutions the influence of particle anisotropy is evaluated. It is claimed that the c 1/2 -dependence is a general feature of solutions of rodlike particles above c ∗ . The experimental results in the crossover region around c ∗ are confirmed by Monte Carlo simulations, based on a model potential describing a screened Coulomb interaction between rods.