Isotropic-Nematic Phase Behaviour of Rods Plus Penetrable Hard Spheres

3 Isotropic-Nematic Phase Behaviour of Rods Plus Penetrable Hard Spheres 

We now consider the effect of added polymer on the phase behaviour of a system of hard rods. We first consider the simplest representation of a polymer the penetrable hard sphere (phs) with diameter a (see Sect. 2.1 for details about this model). 

The starting point for the calculation of the phase behaviour is the semi-grand potential for the system of colloidal rods + phs in osmotic equilibrium with a reservoir with phs, which sets the chemical potential of the phs. This system is depicted in Fig. 6.4. In the free volume approximation (see Sect. 3.3) we can write (3.24) 

6 Phase Transitions in Suspensions of Rod-Like Colloids Plus Polymers 

The opposite limit A 3 1 corresponds to the case when the size of the inserted phs is very large. Then W is, to a good approximation, equal to the volume work needed to create a cavity 

---