Screening blobs close packed

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 ... 

Our preceding discussion focused on systems described in terms of close packed screening blobs. As was previously stressed, such a picture is inherently associated with multichain interactions. Single chain blobs may also occur in systems incorporating many chains. In such situations it is necessary to allow for the effect of chain-chain interactions. The precise method varies with the details of the system. In the following we present two illustrative examples concerned, respectively, with confinement and with Pincus blobs. 

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