Two-state nanocomposite based on symmetric diblock copolymer and planar nanoparticles: mesoscopic simulation†

We study a coarse-grained model of a nanocomposite consisting of a symmetric AB diblock copolymer and a planar nanoparticle (NP) using dissipative particle dynamics. The NP size exceeds the period of the lamellar domains formed by microphase separation of the copolymer blocks. The model predicts that the NP has two stable orientations due to its anisotropic nature and the difference between the NP size and the period of the matrix domains. In the case of good or poor compatibility of the NP with both copolymer blocks, the NP plane is oriented perpendicular to the plane of the matrix domains. In the case of selective interaction with the copolymer, the NP will be incorporated into the domain formed by the blocks with which it has the greatest compatibility. The appearance of the orientational ordering effect is explained by the imbalance in the distribution of copolymer blocks along the NP surface in the early stages of the microphase separation. This result allows us to consider this system as a two-state nanocomposite. It is also observed that the introduction of the NP reduces the incompatibility threshold of the copolymer blocks above which microphase separation occurs. We hope that the reported effect will be useful for the design of smart nanomaterials with switchable properties.