Phase behavior predictions for polymer blends containing reversibly associating endgroups

Abstract

A mean field model is developed to predict how polymer-polymer miscibility changes if polymers are functionalized with noncovalent, reversibly binding endgroups. The free-energy model is based on the Flory-Huggins mixing theory and has been modified using Painter's association model to account for equilibrium selfassociation of endgroups. Model input parameters include the length of polymer chains, a temperature-dependent interaction parameter, and a temperature-dependent equilibrium constant for each type of associating endgroup. The analysis is applied to 12 possible blend combinations involving self-complementary interactions and seven combinations involving hetero-complementary [i.e. donor-acceptor (DA)] interactions. Combinations involve both monofunctional and telechelic associating chains. Predicted phase diagrams illustrate how self-complementary interactions can stabilize two-phase regions and how DA interactions can stabilize single phase regions. The model is a useful tool in understanding the delicate balance between the combinatorial entropy of mixing polymer chains, the repulsive interactions between dissimilar polymers, and the additional enthalpic and entropic changes due to endgroup association of chain ends.

Molecular Approach to Supramolecular Polymer Assembly by Small Angle Neutron Scattering

“…Because of the comparable size of the compound B-block with the step length of the polymer, also no distinction between the rigidity of both blocks was made. Rather easy corrections could account for the ( 1) agg agg agg (11) The relevant contrast factors are…”

Spacer‐length‐dependent association in polymers with multiple‐hydrogen‐bonded end groups

“…[1][2][3][4] Theoretical work has shown that the domain size and morphology of the phase-separated structures critically depend on the strength of the interpolymer noncovalent interactions. [5][6][7][8][9][10] To achieve these attractive enthalpic interpolymer interactions, end-functionalized homopolymers have been prepared with functional groups capable of noncovalent assembly such as hydrogen bonding, [11][12][13][14][15][16][17][18][19][20] ionic, 21 transition-metal, 22,23 host-guest, [24][25][26] and fluorophilic 27 interactions. Typically, these functional groups are attached to a homopolymer via a short, aliphatic spacer.…”

Lattice cluster theory of associating polymers. IV. Phase behavior of telechelic polymer solutions

“…is positive and almost independent of M. 25 The latter observation implies that the sensitivity of the phase stability boundaries of strongly interacting sticky systems to M can be traced to the derivatives ∂ 2 a(φ, M)/∂φ 2 finding enables estimating the spinodal temperature T sp analytically. Applying the spinodal condition from Eq.…”

“…12,20 The effective value y * for the volume fraction y in Eqs. (2) and (3) is determined through maximizing the free energy f s with respect to y, which leads to the relation, 12,20 …”

“…The increasing scientific interest [1][2][3][4][5][6] in telechelics and their significant technological importance [7][8][9][10][11] have motivated our recent investigations 12,13 of basic thermodynamic properties of telechelic solutions, including a study of the dependence of the enthalpy h p and entropy s p of self-assembly and the Flory-Huggins (FH) interaction parameter χ on molecular and thermodynamic variables. While all three interaction parameters have heretofore been treated as purely phenomenological quantities, the lattice cluster theory (LCT) represents them as dependent on the polymer volume fraction φ, temperature T, microscopic van der Waals and self-assembling interaction energies ( , s ), and the length M of the individual telechelic chains.…”