Entropic driving force

Miscibility or compatibility provided by the compatibilizer or TLCP itself can affect the dimensional stability of in situ composites. The feature of ultra-high modulus and low viscosity melt of a nematic liquid crystalline polymer is suitable to induce greater dimensional stability in the composites. For drawn amorphous polymers, if the formed articles are exposed to sufficiently high temperatures, the extended chains are retracted by the entropic driving force of the stretched backbone, similar to the contraction of the stretched rubber network [61,62]. The presence of filler in the extruded articles significantly reduces the total extent of recoil. This can be attributed to the orientation of the fibers in the direction of drawing, which may act as a constraint for a certain amount of polymeric material surrounding them. 

In summary, the combined experimental (NIS, IR- and Raman-spectroscopy) and computational (DFT) approach has enabled the identification of the vibrational modes that contribute most to the entropic driving force for SCO transition. 

The reversible recovery of a deformed elastomer to its original (undeformed) state is due to an entropic driving force. The entropy of polymer chains is minimum in the extended conformation and maximum in the random coil conformation. Cross-linking of an elastomer to form a network structure (IX) is... 

Secondly, iron(II) was observed to form octahedral complexes that incorporate the triamine in preference to the monoamine. When complex 16 was mixed with an equimolar amount of triamine in aqueous solution, complex 14 and monoamine were the only products observed (Scheme 1.15). The chelate effect [40] may be understood to drive this substitution The incorporation of one equivalent of triamine results in the liberation of three equivalents of monoamine, which provided the entropic driving force for this reaction. 

Cram DJ et al (1992) Host-guest complexation 62. Solvophobic and entropic driving forces for forming velcraplexes, which are 4-fold, lock-key dimers in organic media. J Am Chem Soc 114 7748-7765... 

The influence of the entropic driving force can be circumvented automatically, however, by evaluating so-called "real activation enthalpies, AH (Sect. 2.1), from the temperature dependence of the standard rate constant, /j orr, since eqn. (30) can be rewritten as [2b, c]... 

The divergent predictions of theories on entropic surface segregation advocating the surface enrichment in more flexible [184, 186, 205, 206], more stiff [200,204,207,209,214], or both types of molecules [183,208] may be compared with experimental results obtained for blends composed of the statistical olefines E EEx. The more branched (i.e., more flexible) component was found preferred at the free surface (with an exception of enrichment-depletion duality described in Sect. 3.1.2.4) but no segregation was observed at silicon or gold interfaces. This leads to the conclusion [120] that the entropic driving force alone cannot be in charge of the enrichment because in such a case the enrichment... 

Assuming a pure statistical entropic driving force for equilibrium (4) (i.e., corresponds to the ratio of the external symmetry... 

---