Direct and Inverse Micelles of Diblock Copolymers with a Polyelectrolyte Block Effect of Equilibrium Distribution of Counterions

作者：Venev Sergey V; Reineker Peter; Potemkin Igor I^*

来源：Macromolecules, 2010, 43(24): 10735-10742.

DOI：10.1021/ma102264g

We develop a mean field theory of micelle formation in salt free solution of diblock copolymers with a soluble polyelectrolyte block and an insoluble neutral block The so-called three-zone model is used which is a simplified alternative of the Poisson-Boltzmann approximation This model allows to analyze an inhomogeneous distribution of counterions outside the corona (an analogue of Gouy-Chapman layer and Manning condensation) We study both dilute and concentrated solutions Conventional spherical, cylindrical and planar morphologies of "direct (soluble) micelles are considered in the crew-cut regime (short soluble blocks) We also analyze the stability of inverse (insoluble) spherical and cylindrical micelles, which form a dense phase In this phase, the soluble blocks with the solvent form spherical (cylindrical) cores which are embedded in a matrix of the insoluble blocks Phase diagrams of the solution are constructed on the basis of conditions of the true equilibrium, i e, they Include one- and two-phase stability regions as well as triple points We demonstrate that the presence of charged groups practically does not change the phase behavior of the solution at high polymer concentrations In this regime, the main factor governing the swelling of the coronae is the polymer concentration On the other hand, the role of the charged groups at low polymer concentrations is very important The Rayleigh instability prevents formation of nonspherical micelles at low polymer concentrations The charged groups promote stability of the spherical micelles they remain stable at conditions when the neutral spherical micelles change morphology or precipitate

• 出版日期2010-12-28