Surface-field-induced microstructures of asymmetric diblock copolymer nanoparticles

Abstract

The microstructures of asymmetric diblock copolymer nanoparticles were investigated using real-space self-consistent field theory. The nanoparticle boundary provides a spherical confinement in which the highly deformable copolymers are forced into a closed and crowded space. The surface-field-induced effects on the microstructures were examined systematically, and a rich variety of novel structures, such as mixtures of distorted cylinders and spherical lamellae, was observed in the copolymer nanoparticles. Investigations of the free energies indicate that the surface-field-induced structural transitions are of the first order. The formation mechanism of the confinement-induced structures was reasonably elucidated, based on the interactions between the polymer chains and confinement boundaries, and on the spherical symmetry from confinements. Our theoretical results are in good agreement with available simulation and experimental observations.

Frustrated phases under three-dimensional confinement simulated by a set of coupled Cahn–Hilliard equations

“…[1][2][3][4][5] Among the different types of three-dimensional confinements, cylindrical 2,3,6-27 and spherical 11,[28][29][30][31][32][33][34][35][36][37][38][39] confinements have been extensively studied with the aim of developing diverse technological applications such as the design of nanoreactors [40][41][42][43] and sophisticated vehicles possessing a rich internal structure for drug delivery, 44-51 among others. When these dual units interact with one another in large numbers, the interplay between attractive and repulsive forces gives rise to a plethora of self-organized morphologies.…”

Controlling the Formation of Polyhedral Block Copolymer Nanoparticles: Insights from Process Variables and Dynamic Modeling

“…Several computational investigations on BCP systems subjected to spherical confinement have been documented in prior studies. − Numerous attempts to understand BCP particle morphological transformations via simulations have employed coupled Cahn–Hillard (CCH) equations, successfully guiding nanoparticle design . In ref , the authors used the CCH to transform ellipsoidal BCP nanoparticles into onion-like spheres by modulating the parameters, accommodating temperature-induced changes during heating.…”

Confined Self-Assembly of Asymmetric Diblock Copolymers within Silica Nanobowl Arrays

“…Owing to their mutual repulsion, the two dissimilar blocks tend to segregate into different domains, and the spatial extent of the domains is limited by the constraint imposed by the covalent connectivity of the blocks, leading to a so-called microphase separation phenomenon. − The confinement provides a new route to develop unique self-assembled block copolymer (BCP) nanostructures which are not readily available in bulk or thin-film systems. − Compared to that in BCPs self-assembling under one-dimensional (1-D) and two-dimensional (2-D) confinements, polymer chains suffer more severe frustrations during microphase separation under three-dimensional (3-D) confinements. Thus, BCP self-assembly under 3-D confinements may experience unusual microphase separations which could lead to far more complex BCP nanostructures, as suggested by a number of theoretical predictions. − …”