The Polymer Society of Korea

Abstract

Block-copolymer diffusivity D directly reflects the kinetics of phase transitions. As the morphology develops from a mixed state into domains, mobility changes—often sharply near the phase-separation boundary and typically decreasing during domain growth due to increasing constraints.
By tracking D along this pathway, the progression of gelation can be quantitatively assessed. In hydrophilicity-driven gelation, hydrophilic blocks preferentially form a connected network that progressively restricts molecular motion, thereby lowering D. The time evolution of D therefore provides a simple kinetic readout of gelation, linking the growth of network constraints to the characteristic time scales of phase transition.
To access these kinetics efficiently, we use dissipative particle dynamics (DPD). Its coarse-grained, thermally consistent dynamics enable realistic simulations over long times and large length scales, allowing stable measurement of self-diffusivity during phase transitions.