Domain entropic effect

Interfacial electron-transfer reactions between polymer-bonded metal complexes and the substrates in solution phase were studied to show colloid aspects of polymer catalysis. A polymer-bonded metal complex often shows a specifically catalytic behavior, because the electron-transfer reactivity is strongly affected by the pol)rmer matrix that surrounds the complex. The electron-transfer reaction of the amphiphilic block copol)rmer-bonded Cu(II) complex with Fe(II)(phenanthroline)3 proceeded due to a favorable entropic contribution, which indicated hydrophobic environmental effect of the copolymer. An electrochemical study of the electron-transfer reaction between a poly(xylylviologen) coated electrode and Fe(III) ion gave the diffusion constants of mass-transfer and electron-exchange and the rate constant of electron-transfer in the macromolecular domain. 

Fig. 20 Experimental evidence for elevations Qess folded states) at the edge of the crystalline domains and for the rim-hole patterns related to the predictions of the simulation model. The left part shows the formation of high elevations at edges and rim-hole patterns in short chain PEO-2k crystals after long relaxation times at room temperature (RT). In the right part, analogous morphologies are obtained by annealing two-dimensional PS-PEO(3-3) crystals. Basicidly, the copolymer shows the same properties as the homopolymer. However, the non-crystallizable polystyrene block affects the ordering process of PEO chains in the crystal and therefore influences both the entropic barrier and the melting enthalpy (expressed by the effective temperature T in the simulations)...

In summary, there are two entropically driven processes for surface concentration of the P[3F-co-BrOx] soft block. 3F repeat units are surface concentrated by virtue of low surface energy, immiscibility, and side chain length that mimics an end-group. BrOx repeat units are miscible with the PTMO domain of the bulk phase and lack an end-group-like architecture. The latter provides a contravening effect that works against surface concentration in the chosen bulk polyurethane. 

---