Hydrogen Bonding in Supramolecular <i>AB</i> / <i>C</i> Melts: From Negative χ to Coherent-States Theory

We revisit the phase behavior of supramolecular AB/C polymer blends using a coherent-states supramolecular interaction model (CS-SIM), which explicitly captures reversible hydrogen bonding through one-to-one associations between A and C segments. By comparing CS-SIM predictions with those from the conventional auxiliary-field attractive interaction model (AF-AIM) based on the negative χ approach, we investigate how bond strength and C homopolymer molecular weight impact microphase transitions. While both models yield qualitatively similar phase diagrams, CS-SIM captures the bond saturation effect, which avoids the overestimation of phase transitions seen in AF-AIM. In addition, it provides direct access to bonding statistics and spatial distributions, enabling interpretation of phase behavior in terms of the underlying supramolecular physics. With the versatile and physically grounded CS-SIM framework in hand, we further investigate the influence of reactive site placement along the polymer backbone on bond spatial distribution and phase behavior.