Effect of Solvent Molecular Size on the Self‐Assembly of Amphiphilic Diblock Copolymer in Selective Solvent

Abstract

Real‐space self‐consistent field theory (SCFT) is employed to study the effect of solvent molecular size on the self‐assembly of amphiphilic diblock copolymer in selective solvent. The phase diagrams in wide ranges of interaction parameters and solvent molecular size were obtained in present study. The results indicate that the solvent molecular size is a key factor that determines the self‐assembly of amphiphilic diblock copolymer. The self‐assembled morphology changes from circle‐like micelle to line‐like micelle, then to loop‐like micelle by decreasing the solvent molecular size in a wide range of solvent selectivity. We analyze and discuss this change in terms of the solvent solubility and the entropy contribution.magnified image

The Origins of Toroidal Micelles from a Liquid–Crystalline Triblock Copolymer†

“…However, this prediction was contradicted by the observation shown in Figure 5(d) that the toroidal micelle yield did not change significantly from Figure 1. As concluded by other researchers, [ 6a‐c,6f,17 ] the formation of toroidal micelles might be pathway‐dependent, but this does not necessarily mean that toroidal micelles are not thermodynamically stable structures. Morphologically, the toroidal micelles are not significantly different from cylindrical micelles from their structures, and energetically the toroidal micelles are very similar to that of the cylindrical…”

“…These rules seemed to apply in most of the reported investigations of toroidal micelles from amorphous block copolymers. [ 6a,b,f,17b,c ] However, our system met none of the three requirements. Firstly, the rigid PFMA core of the cylinders yielded a high bending modulus.…”

“…Other researchers have shown both experimentally [ 6b,17 ] and theoretically [ 18 ] that the formation of toroidal micelles is highly pathway‐dependent and can be influenced by many factors. For example, Jiang and coworkers showed that decreasing the temperature, [ 6f ] increasing the shearing flow rate, [ 17b ] addition of small interacting molecules [ 19 ] could all facilitate the formation of toroidal micelles. In the current system, several influencing factors were found as well, including the thermal history, solvent composition, and the stirring rate of the samples.…”

“…Jiang and coworkers showed that the formation of toroidal micelles was greatly influenced by the stirring rate of the solution. [ 17b ] At low shear rates, the toroidal micelles were formed through an end‐to‐end fusion of cylindrical micelles, while a rod‐to‐sphere‐to‐vesicle‐to‐toroid morphological transition was observed at high shearing rates. In our case, however, the influence of the shear flow rate was less complex.…”

Virtual Free-Radical Polymerization of Vinyl Monomers in View of Digital Twins

“…The interaction of terminated chains determines the formation of the main bulk of the polymer material. The result of each of these elementary processes is greatly influenced by the interaction of their components with solvent molecules [ 25 ].…”