Effect of distribution of stickers along backbone on temperature-dependent structural properties in associative polymer solutions

Abstract

Effect of distribution of stickers along the backbone on structural properties in associating polymer solutions is studied using self-consistent field lattice model. Only two inhomogeneous morphologies, i.e., microfluctuation homogenous (MFH) and micelle morphologies, are observed. If the system is cooled, the solvent content within the aggregates decreases. When the spacing of stickers along the backbone is increased the temperaturedependent range of aggregation in MFH morphology and half-width of specific heat peak for homogenous solutions-MFH transition increase, and the symmetry of the peak decreases. However, with increasing spacing of stickers, the above three corresponding quantities related to micelles behave differently. It is demonstrated that the broad nature of the observed transitions can be ascribed to the structural changes which accompany the replacement of solvents in aggregates by polymer, which is consistent with the experimental conclusion. It is found that different effect of spacing of stickers on the two transitions can be interpreted in terms of intrachain and interchain associations.

Effect of polymer concentration and length of hydrophobic end block on the unimer-micelle transition broadness in amphiphilic ABA symmetric triblock copolymer solutions

“…Above the transition region most copolymer molecules are in micelles. It is verified theoretically [5] and experimentally [6] that the broad nature should be ascribed to the structural changes which accompany the replacement of micellar core solvent by polymer. However, the effect of the hydrophobic block on the structural changes is not clarified so far, which is very important in high polymer concentration regimes.…”

“…Effect of polymer concentration and length of end block The half-width of a specific heat peak may be an intrinsic measure of transition broadness. [5,22]. In this work, the heat capacity per site of amphiphilic ABA symmetric triblock copolymers is expressed as (in the unit of k B ): figure 3 (a), the half-width of the transition peak rises, and the symmetry and the height of the transition peak decrease.…”

“…In this report, a SCFT lattice model is applied [14][15][16]. In earlier publications, we have used the SCFT lattice model to study the phase behavior of physically associating polymer solutions [5,17,18]. It is established that the temperature-dependent behavior of aggregates is affinitive to chain architecture [5], and the effect of polymer concentration is in a way similar to that of chain architecture [18].…”

Self-assembly in rod/coil block copolymers: Degenerate behavior under nonconfinement

“…In our previous works we used the SCFT lattice model to study the phase behaviors in associative polymer solutions [39][40][41][42] and in coil-rod-coil ABC triblock copolymers [44]. The effect of asymmetry of the coil block on the microphase separation was focused on a series of fixed rod fractions.…”

Self-consistent field theoretic simulations of amphiphilic triblock copolymer solutions: Polymer concentration and chain length effects

“…It is found that the broadness of transition is affected by the length of hydrophobic end blocks (i.e., chain length). However, in associative polymers [11], when the total length of hydrophilic blocks is decreased, keeping the chain length constant, the broadness of transition concerned micelles increases. It is an obvious conclusion drawn that the broadness of the transition changes due to the length ratio of hydrophobic to hydrophilic blocks.…”