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

Han Han,Zhang Zhang,Ma Ma

doi:10.5488/cmp.15.33602

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 temperature-dependent 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.

Highlights

Associating polymers are polymer chains containing a small fraction of attractive groups along the backbones
The properties of associative polymer solutions depend on four tunable parameters: χ is the Flory-Huggins interaction parameter, N is the degree of polymerization of chain, where N equals 81 in this paper, l is the spacing of stickers along the backbone and φst is the average volume fraction of polymers
At fixed l, when χ is increased from homogenous solutions, microfluctuation homogenous (MFH) and micelle morphologies appear in turn. φP(r ) and φst(r ) in the solutions with MFH morphology slightly fluctuate around φP and φst, respectively

Summary

Introduction

Associating polymers are polymer chains containing a small fraction of attractive groups along the backbones. The junctions can be broken and recombined frequently on experimental time scales This property of the junctions makes associative polymer solutions behave reversibly when ambient conditions, such as temperature and concentrations, change. The study of the effect of distribution of sticker along the chain in physically association polymer solutions (PAPSs) would be useful to establish and understand the thermodynamics of block copolymers in a selective solvent. It is well-known that self-consistent field theory (SCFT), as a mean-field theory, has been applied to the study of a great deal of problems in polymeric systems [19,20,21,22,23]. It is found that this result can be interpreted in terms of intrachain and interchain associations

Theory

Result and discussion

Conclusion and summary