SCF Study of Amphiphilic Micellar Shells Containing Polyelectrolyte and Hydrophobic Sequences

Abstract

The behavior of amphiphilic polyelectrolyte shells of micelles with kinetically frozen hydrophobic cores in aqueous solutions was studied by self-consistent field calculations. The calculations emulate the behavior of annealed (weak) shell-forming polyelectrolyte chains, e.g., poly(methacrylic acid), PMA, containing a relatively low fraction of strongly hydrophobic units, e.g., polystyrene, PS. The hydrophobic units are arranged either in sequences, or are distributed uniformly in the shell-forming chains. The analysis of concentration profiles of individual species reveals strong segregation and important self-organization of hydrophobic units in the shell. Hydrophobic units either adsorb at the core, or form small hydrophobic domains relatively far from the core. The transition from one type of conformations to the other, which depends on the position of hydrophobic sequence in the polyelectrolyte chain, can be provoked by changes in pH and ionic strength. The behavior of shell-forming chains composed of a long inner polyelectrolyte sequence (grafted to the micellar core), a short middle hydrophobic sequence and a peripheral polyelectrolyte sequence is of interest. The calculations yield a bimodal distribution of hydrophobic units as a function of the radial distance from the core/shell interface. It means that two types of chains (fairly stretched and loop-forming ones) coexist in the shell.

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

“…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]. Recently, SCFT is applied to the study of the properties of micelles in polymer solutions [24][25][26]. In previous paper [27], we focused on the thermodynamic properties and structure transitions in PAPSs.…”

Spherical brushes within spherical cavities: A self-consistent field and Monte Carlo study

“…Spherical polymer brushes are very interesting systems due to their multiple possible uses: drug delivering, 1,36 stabilization of colloidal particles, 37,38 mimicking of hard spheres, 39 creation of bioinspired materials, 40 smart catalyst, 9 etc. The study and characterization of polymer and polyelectrolyte spherical brushes have received considerable attention including experimental works, 41,42 theoretical 33,43,44 and selfconsistent field ͑SCF͒ developments, [44][45][46][47][48][49][50][51] as well as numerical simulations. 17,32,42,[52][53][54][55][56][57][58] The determination of the pairwise interaction [59][60][61][62][63][64] and the study of solutions of spherical brushes [65][66][67][68] have also been studied extensively.…”

Theoretical Modeling of Chemical Equilibrium in Weak Polyelectrolyte Layers on Curved Nanosystems

“…For weak PE brushes on NPs, the presence of the surface also critically affects the molecular organization of the chains. Theoretical methods, including scaling theory [ 85 ], mean-field approximation approaches [ 86 ], numerical SCF methods [ 87 ], and SF-SCF calculations [ 88 , 89 , 90 ], have contributed greatly to what we know about the effect of bulk pH, salt concentration, and surface density of chains on the conformational properties and the distribution of charge of weak PE grafted to curved surfaces. In a work combining grand canonical titration Monte Carlo simulations of coarse-grained weak PE chains end-tethered to a spherical NP in a salt solution, Barr and Panagiotopoulos investigated the effect of solvent quality and pH of the solution on the ionization state of the monomers and the phase behavior of the grafted layer [ 70 ].…”