Phase Behavior of Block Copolymer Nanocomposite Systems

Abstract

Nanocomposite materials made of block copolymer (BCP) and nanoparticles display properties which can be different from the purely polymeric matrix. The resulting material is a crossover of the original properties of the BCP and the presence of the assembled nanoparticles. A mesoscopic study using cell dynamic simulations is reported, to quantitatively describe the structural properties of such hybrid materials. The most relevant parameters are identified to be the fraction of nanoparticles in the system and its chemical affinity, while the nanoparticle size with respect to the BCP length scales plays a role in the assembly. The morphological phase diagram of the BCP is constructed for nanoparticles with chemical affinity ranging from A-compatible to B-compatible for a symmetric A-B diblock copolymer. Block-compatible nanoparticles are found to induce a phase transition due to changes in the effective concentration of the hosting phase, while interface-compatible particles induce the appearance of two new phases due to the saturation of the diblock copolymer interface.

Nematic Ordering of Anisotropic Nanoparticles in Block Copolymers

“…The BCP phase is shown to transition from hexagonally ordered A-majority circular to lamellar (blue circles to black squares) and from lamellar to B-majority circles (black squares to red circles) in the presence of NPs. While this behavior is consistent with simpler isotropic NPs [25,36,57] and homopolymer additives, [58,59] two additional distinct features can be observed. First, the lamellar phase space is enhanced in the presence of anisotropic NPs, which is due to the NP anisotropy that effective swells the BCP domains.…”

“…Contrary to that, Figure 1a top-right region shows lack of nematic ordering at same volume fraction as (b) and (c). Furthermore, in Figure 1 the lamellar phase space is enhanced compared to isotropic NPs, [57] which motivates the study of the role of NP anisotropy in the co-assembly.…”

“…Isotropic NPs have been shown to induce phase transitions in the BCP morphology due to the changes in the effective concentration of the hosting domains. [25,36,57] Nonetheless, in this work we focus on the collective alignment of NPs with the BCP matrix and with themselves. In 2D, rhomboidal particles with n = 0.6 are used.…”

Conductivity of diblock copolymer system filled with conducting nano‐particles: Effect of copolymer morphology

“…While the distribution of fillers in simplest morphologies (e.g., lamellae) and their effect on the thermodynamics 6,19 of DBC are investigated, to some extent, both experimentally 1,2,30 and theoretically, 5,19,[31][32][33][34] the electrical properties of filled DBC has not yet received proper research attention. In our recent work, in refs.…”

Density Functional Theory for Polymer Phase Separations Induced by Coupling of Chemical Reaction and Elastic Stress

“…Based on the minimization of the free energy and the dissipation functional, DFT enables us to simulate mesoscopic phase separation dynamics by tracking a few numbers of order parameters that characterize the system. [18][19][20][21] In our simulation, we consider a three-component system that is composed of non-crosslinked polymer, crosslinked polymer, and solvent. A non-crosslinked polymer chain changes into a crosslinked polymer chain via chemical reaction.…”