Short-range orientational order in polymer-solvent systems

Conformational and hydrodynamic parameters of hyperbranched pyridylphenylene polymers

“…Similar significant differences in electro‐optical characteristics of polymers in polar and non‐polar solvents have been observed before . These differences are caused by orientational correlation of polar solvent molecules with respect to a macromolecule; the latter acquires a dipole moment, which manifests itself as a permanent dipole in electro‐optical experiments.…”

Mesogen Molecules Orientation on Crystal Surfaces

“…Recently by using such method of atom-atom potential the short-range orientational order in polymer-solvent system has been investigated and good agreement of both theoretical results and experimental data has been obtained [19].…”

Flow-Induced Protein Chain Deformation, Segmental Orientation, and Phase Separation in Native Silk Feedstock

“…Various studies have suggested the importance of a critical shear rate, shear stress, or energy accumulation to initiate gelation. − ,− It is well known that flow can produce chain deformation and orientation in polymer solutions − and silk fibers are highly oriented at the molecular, crystalline, and fibrillar levels; − hence, it seems likely that some aspect of flow-induced chain deformation and orientation may underpin the gelation process. Based on the hypothesis of an “entropically penalized hydration shell” enslaved to the fibroin, it was suggested previously that flow-induced gelation may occur through desolvation due to chain deformation causing a further loss of entropy of the bound water.…”

“…Standard molecular theories of polymer elasticity describe the chains as “entropic springs”, for which stretching restricts the number of accessible conformations and causes an increase in free energy through the corresponding loss of entropy. − Consequently, this explanation of flow-induced gelation assumes that the accessibility of chain conformations also affects the entropy of the associated hydration shell. In this respect, it is interesting that several researchers ,, have reported correlations between the orientation of polymer chain segments and the associated solvent, suggesting that any constraints on the motion of the former will also apply to the latter.…”

“…57−61 Consequently, this explanation of flow-induced gelation assumes that the accessibility of chain conformations also affects the entropy of the associated hydration shell. In this respect, it is interesting that several researchers 39,62,63 have reported correlations between the orientation of polymer chain segments and the associated solvent, suggesting that any constraints on the motion of the former will also apply to the latter. A closer examination of the entropically penalized solvation shell hypothesis has been reported recently, 64 which suggested that the loss of independent motion caused a significant decrease in both the heat capacity (C p ) and entropy (ΔS) of the bound water relative to free water.…”