Segregation effects, polymer surfaces copolymers

Differences are observed for both surface and bulk conductivities of one CB in various polymers as for example when Narkis et al. [19] compare PP, PS, HIPS, PE, Noryl . There is even a subtle effect of composition on resistivity in the case of PP homopolymer versus P P copolymer because the latter contains a rubbery component (Table 18.4). The CB apparently segregates into the rubbery phase and a higher loading of CB is needed to reach levels of conductivity comparable to the homopolymer [19]. Effects oftitanate surface treatments on the conductivity of CB compounds are included in Chapter 5. 

Polymer blends may be expected to reflect the balance of forces that control their phase structure in the bulk. If two polymers are compatible in the bulk, they may or may not segregate in the surface depending on the balance of forces. Materials that are able to phase separate will segregate in the surface, and generally speaking the lower surface energy material will move towards the free air surface. This effect was illustrated in Chapter 9 in the case of the surface segregation of the ether soft block in the case of block polyurethane copolymers. 

In this review, we introduce another approach to study the multiscale structures of polymer materials based on a lattice model. We first show the development of a Helmholtz energy model of mixing for polymers based on close-packed lattice model by combining molecular simulation with statistical mechanics. Then, holes are introduced to account for the effect of pressure. Combined with WDA, this model of Helmholtz energy is further applied to develop a new lattice DFT to calculate the adsorption of polymers at solid-liquid interface. Finally, we develop a framework based on the strong segregation limit (SSL) theory to predict the morphologies of micro-phase separation of diblock copolymers confined in curved surfaces. 

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