Effect of the Solvent on Polymer Incompatibility in Solution

Abstract

It is generally held that the incompatibility of polymers in solution arises from an unfavorable interaction (X23) between segments of the polymers and is independent of the polymer-solvent interactions (Xi2 and Xi3). This is correct when the polymer-solvent interactions are of equal magnitude, as assumed in Scott's original treatment of such ternary systems. We reexamine the theory, calculating spinodals which show that a small difference in polymer-solvent interactions has a marked effect on polymer incompatibility. This is in agreement with experimental findings of Dondos and others. At high polymer concentration, polymer incompatibility is associated with X23, but at low concentrations it should be mainly due to the difference between Xi2 and Xi3. Setting X23 = 0 but keeping a sufficient difference between Xi2 and 33 leads to a closed region of incomplete miscibility within the triangular phase diagram, although the binaries show complete miscibility.

Differentiation of Human Adipose-Derived Stem Cells into Neuron-Like Cells Which Are Compatible with Photocurable Three-Dimensional Scaffolds

“…These results were consistent with the previously published studies. 1,2,4,7,21,22 To further determine their multipotential differentiation capability, trilineage differentiation toward adipocytes, osteoblast, and chondrocytes was induced with specific induction medium. hADSCs show their stem cell properties and can also be specifically induced into NLCs by a cocktail induction protocol, which is consistent with the previous reports.…”

“…20,21 Chitosan, a naturally abundant degradable polysaccharide, has been used to prepare porous scaffolds for stem cell-based tissue regeneration. For example, Schwartz et al reported that chitosan is quite suitable for the induction of the chondrogenic differentiation of the human bone marrow mesenchymal stem cells.…”

On the one‐phase state of aqueous protein‐uncharged polymer systems: Casein‐guar gum system

“…Let us consider the effect of ionic strength on the phase state from the point of view of the general theoretical concepts relative to the relations between the intensity of polymer-solvent and polymerpolymer interactions, and the phase state of polymer/polymer/solvent systems. 2,50,51 Compatibility between caseinate and guar in water at low ionic strength when the pH is above the isoelectric point of casein can be ascribed to two causes: the formation of weak soluble interpolymer complexes, which dissociate when ionic strength rises; and/or the vanishing of the difference in the thermodynamic interaction parameter between each of the biopolymers and water. The second one seems unlikely, because caseinate is thermodynamically incompatible with PEG in the absence, as well as in the presence, of salt (Fig.…”

Influence of Competition Between Binary Pairwise Interactions on the Phase Behavior in Ternary Blends

“…Zeman and Patterson [1] were the first to demonstrate in their study of polymer solutions that the phase behavior in ternary systems was determined mainly by the asymmetry in the polymer-solvent interactions, the so-called ⌬ effect (⌬ = 12 Ϫ 13 ), which has been illustrated for a number of systems [2][3][4][5][6]. However, until now, little work on the influence of the difference of molecular weights between different components on the asymmetry of the polymer-polymer interactions has been reported [7].…”

“…In a binary polymer blend (designated components 1 and 2), there is only one binary interaction pair (1)(2), and miscibility in the system is judged by the criterion 12 р 12 crit , where crit = 0.5 (N Ϫ 0. and N i is the degree of polymerization of component i. There are three such binary pairs (1-2, 1-3 and 2-3) in a ternary polymer blend (designated 1, 2 and 3), and the interaction between any two of the components will be influenced by the third one, which has the opportunity to interact with other components as well.…”