Amphiphilic Graft Copolymer in a Selective Solvent:  Intramolecular Structures and Conformational Transitions

Abstract

We present a scaling theory for the equilibrium conformations of amphiphilic comblike (graft-) copolymer in dilute solution. We examine intramolecular self-assembly upon inferior solvent strength for the backbone. We demonstrate that at sufficiently dense grafting the backbone collapses via formation of a pearl necklace of intrachain micelles that are stabilized by steric repulsion between coronas. This behavior is reminiscent to the Rayleigh instability in hydrophobic polyelectrolyte, though occurs in a neutral macromolecule. The equilibrium local structure and the persistence length of comblike copolymer are analyzed as a function of solvent strength. Repulsion between micellar coronas leads to swelling of comblike macromolecule on larger scales and ensures the thermodynamic stability of the solution with respect to phase separation. In the case of sparse grafting we predict formation of not only spherical but also cylindrical intramolecular micelles and lamellar mesophases.

Interpolyelectrolyte Complexes Based on Polyionic Species of Branched Topology

“…For the specific system considered here, the effective long-range repulsions arise because of interactions between the side chains forming the cylindrical corona of the IPEC. Similar pearl-necklace structures have previously been theoretically predicted and experimentally observed for amphiphilic cylindrical brushes in selective solvents [90][91][92]. Figure 10 presents the radial distributions of the terminal segments of the side chains of the cylindrical PE brush in the complex with oppositely charged linear GPE chains.…”

Coarse-grained models for macromolecular systems

“…The different morphologies found in our simulations can be compared with the theoretical work based on scaling arguments by Borisov and Zhulina [38] on amphiphilic graft copolymers with hydrophobic backbone: They predict the formation of analogous structures (necklace of star-like or crew-cut micelles, cylindrical worm-like micelle and lamellar structure) depending on the degree of branching of the copolymer and the solvent quality. Despite the different connectivity constraints for the two polymers, sparse grafting may be compared to high substitution rate and dense grafting corresponds to multiblock copolymers with few associating monomers.…”

Hydrophobically Modified Sulfonated Polyacrylamides for IOR: Correlations between Associative Behavior and Injectivity in the Diluted Regime

“…Various techniques have been implemented among which viscosimetry [4][5][6][7][8][9][10][11][12], fluorescence [13][14][15][16], transmission, scanning and environmental scanning electron microscopy (TEM, SEM and ESEM) [16][17][18], 19 F NMR spectroscopy [19,20], neutron scattering [21][22][23][24] and Static and Dynamic Light Scattering (SLS and DLS) [14][15][16][25][26][27][28][29][30][31][32][33][34][35][36][37]. Theoretical approaches have also been proposed to describe HMWSP static [38,39] and dynamic [40] properties. Although intrachain associations are often reported as being dominant over interchain associations in the diluted regime, the conclusions of the different studies are largely dependent on the HMWSP microstructure, the chemical composition of the various constituents and the physicochemical conditions (salinity, pH and temperature).…”