Dissipative Particle Dynamics Study of the Structural Inversion Process of pH-Responsive Polymeric Micelles

作者：del Rosario Rodriguez Hidalgo Maria; Soto Figueroa Cesar; Vicente Luis^*

来源：Macromolecular Theory and Simulations, 2014, 23(1): 49-58.

DOI：10.1002/mats.201300131

• DPD molecular modeling
• Flory-Huggins interaction parameter
• micellar inversion
• stimuli-responsive polymers

The thermodynamic stability and structural inversion process of polymeric micelles is explored that are formed by the purely pH-responsive poly(methacrylic acid)-b-poly((2-diethylamino)ethyl methacrylate) (PMAA-b-PDEA) diblock copolymer in aqueous environment with different pH (from pH 2 to 12) employing dissipative particle dynamics (DPD) simulations and coarse-grained models. In acid environments, thermodynamically stable micelles can be generated with well-defined micellar structures of a PMAA-core and PDEA-corona by protonation of the amine groups of PDEA segments. In stark contrast, in alkaline environments, the polymeric micelles invert their micellar structure (PDEA-core and PMAA-corona) by ionization of the carboxylic acid groups of PMAA segments. The mesoscopic simulations, which agree with experimental outcomes, reveal an isoelectric point at pH 7.2 and a wide pH interval where the polymeric micelles lose their thermodynamic stability and tend to precipitate. The structural inversion process triggered by the pH effect is characterized by a simultaneous immersion and ascent of polymeric segments.

• 出版日期2014-1