Preparation of superstructured comb polymers based on tadpole-shaped single-chain nanoparticles†

Abstract

Compared with the formation of individual elements, the creation of superstructures often yields exceptional properties. This approach has been applied to assemble diverse synthetic building blocks (molecules, macromolecules, inorganic nanoparticles, etc.) into highly organized constructs. In the present study, a novel comb polymer superstructure is developed via the grafting of tadpole-shaped single-chain nanoparticles (T-SCNPs) onto a high-molecular-weight linear backbone (H-LP). The resulting superstructure (comb of T-SCNPs), which utilizes T-SCNPs as building blocks, exhibits distinct rheological behavior in solution. The influences of the microstructure and related parameters (specifically the relaxation time (τ_R) and mesh size (ξ) of the entangled chains) on the macroscopic properties (modulus and viscosity) of this complex topological structure in solution are investigated. Compared with conventional comb macromolecules (comb of F-LPs) and blends of SCNPs with high-molecular-weight polymers (SCNPs&H-LP), T-SCNP combs exhibit significantly reduced chain entanglement, faster τ_R, and larger ξ in solution, resulting in a substantially decreased viscosity (up to 90%). Furthermore, our research underscores the intricate relationship between these rheological properties and the size and concentration of grafted T-SCNPs. As the size or concentration of T-SCNPs increases, the mesh size of the entangled chains expands, which leads to increased τ_R and decreased viscosity.