Sterically Stabilized Colloidal Boehmite Rods Polymer

3 Sterically Stabilized Colloidal Boehmite Rods + Polymer 

As mentioned in the introduction of this chapter, suspensions of rod-like inorganic colloids were the first systems in which the I-N transition was observed. In the early 1960s Zocher and Torok [39—41] and Bugosch [42] observed interesting 

Burning and Lekkerkerker [37] observed isotropic—nematic phase separation in a dispersion of sterically stabilized boehmite rods, which approximate hard rods, in cyclohexane. Buitenhuis et al. [43] studied the effect of added 35 kDa polystyrene (/ g = 5.9nm) on the hquid crystal phase behaviour of sterically stabilized boehmite rods with average length L = 1.1 nm and average diameter D = ll.lnm in ortho-dichlorobenzene. Different phase equihbria were observed. Two biphasic equilibria dilute isotropic phase Ij + nematic N, concentrated isotropic phase I2 + nematic N and a triphasic equilibrium 1 -F I2 + N (see photo. Fig. 6.20). In this system the boehmite rods are quite polydisperse. Therefore comparison with theory should be done with an approach including polydisperse rods. We further note no li +12 coexistence was observed experimentally but 

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

6 Phase Diagrams of Rod/Polymer Mixtures Including Highly Ordered Phases 

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