Shear-driven segregation kinetics in binary polymer blends: Insights from dissipative-particle-dynamics simulations

This study investigates the phase separation kinetics of binary (AB) polymer blends under various shear conditions using dissipative particle dynamics simulations. The system, confined by two parallel walls, is subjected to different shear cases, including stationary and moving walls. The simulations explore critical and off-critical polymer compositions, analyzing morphological evolution, scaling behavior, domain growth, and structural anisotropy. Our results indicate shear-induced alignment and thinning of polymer domains. The characteristic length scales exhibit power-law growth: R(t)∼t^{ϕ}, where ϕ is the effective growth exponent. Initially, the system displays viscous hydrodynamic growth with an exponent of ϕ∼1. As time progresses, this transitions to inertial hydrodynamic growth characterized by ϕ∼2/3. Additionally, for off-critical mixtures, the inertial growth exponent slightly reduces as the shear rate increases. Higher shear rates result in anisotropic structures, such as deformed cylindrical domains in off-critical blends and distorted lamellae in critical mixtures. The findings provide insights into manipulating polymer morphologies under shear, offering pathways for industrial applications in materials design and processing.