Growth kinetics and morphology characterization of binary polymeric fluid under random photo-illumination

AK Singh and A Chauhan and A Singh, JOURNAL OF CHEMICAL PHYSICS, 160, 024907 (2024).

DOI: 10.1063/5.0181688

We present a comprehensive study using dissipative particle dynamics simulations to investigate phase separation kinetics (PSK) in three- dimensional (3d) polymeric fluids under random photo-illumination. We consider two scenarios: polymer blends with active radicals at one end of each immiscible chain and block copolymer (BCP) melts with photosensitive bonds linking incompatible blocks. The phase separation (PS) is induced by temperature quench of the initial homogeneously mixed system. Simultaneously, the system experiences random photo- illumination, simulated by two concurrent random events: (a) the recombination of active radicals in polymer blends and (b) the breaking of photosensitive bonds in BCP chains. Variations in the bond-breaking probability, P-b, mimic the change in light intensity. The length scale follows power law growth, R(t) similar to t(phi), where phi represents the growth exponent. Increasing P-b results in a gradual transition in growth kinetics from micro-PS to macro-PS, accompanied by corresponding transition probabilities for both systems. Micro-PSK dominates the evolution process at low P-b values. The scaling functions exhibit data overlap for most scaled distances, indicating the statistical self- similarity of evolving patterns. Our study enhances the understanding of PSK in polymeric fluids, revealing the impact of photosensitive bonds and active radicals. Furthermore, it suggests the potential for designing novel polymeric materials with desired properties.

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