Binary interactions, blobs

Free, isolated, collapsed chains may be viewed as a spherical arrays of close packed collapse blobs. Collapse blobs, like screening blobs, occur because of binary monomer-monomer interactions. However, screening blobs occur in good solvents when the binary interactions are repulsive while collapse blobs resiJt from attractive monomer-monomer interactions in a poor solvent. When the temperature is not too far below the 6 temperature, the associated interaction energy is weak enough so as not to perturb the Gaussian behavior of short chain segments. Quantitatively the collapse blob is defined by the combination of vg / c ... 

The first theories that implemented a proper balance of intramolecular interactions and conformational elasticity of the branches were developed by Daoud and Cotton [21] and by Zhulina and Birshtein [22-24]. These theories use scaling concepts (the blob model), originally developed by de Gennes and Alexander to describe the structure of semidilute polymer solutions [64] and planar polymer brushes [65, 66]. Here, the monomer-monomer interactions were incorporated on the level of binary or ternary contacts (corresponding to good and theta-solvent conditions, respectively), and both dilute and semidilute solutions of star polymers were considered. Depending on the solvent quality and the intrinsic stiffness of the arms, the branches of a star could be locally swollen, or exhibit Gaussian statistics [22-24]. 

AT=Tci-T = 8 °C where T is the temperature of the measurements and Tci is the doud point. DOP is a neutral solvent for PS and PB and weakens repulsive segmental interactions between PS and PB. ° The system can be approximately treated as a pseudo-binciry system where a phase separation between PS and PB occurs in the medium of DOP and the phase separation between the polymers and the solvent is insignificant. The pseudo-binary system is regarded to be equivalent to bulk systems when the segments of polymers in bulk are replaced by the blobs, as already pointed out at the beginning of Section 2.30.2.1. 

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