  We study the phase separation kinetics of miktoarm star polymer (MSP) melts
and blends with diverse architectures using dissipative particle dynamics
simulations. Our study focuses on symmetric and asymmetric miktoarm star
polymer (SMSP/AMSP) mixtures based on arm composition and number. For a fixed
MSP chain size, the characteristic microphase-separated domains initially show
diffusive growth with a growth exponent $\phi \sim 1/3$ for both melts that
gradually crossover to saturation at late times. The simulation results
demonstrate that the evolution morphology of SMSP melts exhibits perfect
dynamic scaling with varying arm numbers; the time scale follows a power-law
decay with an exponent $\theta \simeq 1$ as the number of arms increases. The
structural constraints on AMSP melts cause the domain growth rate to decrease
as the number of one type of arms increases while their length remains fixed.
This increase in the number of arms for AMSP corresponds to increased
off-criticality. The saturation length in AMSP follows a power law increase
with an exponent $\lambda \simeq 2/3$ as off-criticality decreases.
Additionally, macrophase separation kinetics in SMSP/AMSP blends show a
transition from viscous ($\phi \sim 1$) to inertial ($\phi \sim 2/3$)
hydrodynamic growth regimes at late times; this exhibits the same dynamical
universality class as linear polymer blends, with slight deviations at early
stages.
