Phase separation kinetics of block copolymer melts confined under moving parallel walls: A DPD study

Singh, Ashish Kumar; Singh, Awaneesh

doi:10.1016/j.commatsci.2023.112224

Cited by 4 publications

(1 citation statement)

References 79 publications

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“…Our simulation model does not target any specific polymeric system; we employed commonly used rigidity parameters: k b = 128 and k a = 5 (in reduced DPD units) for all bonds and angles in DPD simulations for flexible polymer chains. ,,,, It is important to note that longer polymer chains may encounter bond crossing. To mitigate this, one can employ the modified segmental repulsive potential (mSRP) − or FENE , potential. However, integrating these potentials during the ATRP process is challenging.…”

Section: Simulation Methodologymentioning

confidence: 99%

Evolution Kinetics of Stabilizing Pickering Emulsion by Brush-Modified Janus Particles: DPD Simulation and Experimental Insights

Shrivastava,

Upadhyay,

Pradhan

et al. 2024

Langmuir

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In the present study, we report the evolution of stabilizing Pickering emulsions using brush-modified Janus particles (JPs), utilizing the dissipative particle dynamics (DPD) simulation technique. Our results are subsequently corroborated with experimental findings. Each JP has one-half of the hydrophobic surface, with the other half embedded with hydrophilic polymer brushes grown via atom transfer radical polymerization (ATRP). Our generic simulation model analyzes the chemical kinetics of polymer brush growth on one-half of the initiator-embedded microparticle (MP) surface, resulting in the formation of JP. This involves evaluating monomer conversion and reaction rates. Our results exhibit a substantial influence of the number of JPs, grafted brush density, and brush length on oil-inwater emulsion stability. We studied the evolution kinetics and stability of emulsion formation by analyzing the growth of average domain size and corresponding scaling functions up to a late time limit. This study aims to clarify the connection between the size, quantity, and functionality of JPs and the stability of Pickering emulsions.

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Section: Simulation Methodologymentioning

confidence: 99%

Evolution Kinetics of Stabilizing Pickering Emulsion by Brush-Modified Janus Particles: DPD Simulation and Experimental Insights

Shrivastava,

Upadhyay,

Pradhan

et al. 2024

Langmuir

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Nonlinear Melt Rheology of Lamellae Forming Polystyrene‐b‐Poly‐2‐Vinylpyridine Diblock Copolymers

Heck,

Wilhelm

2024

Macro Chemistry & Physics

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Lamellae forming polystyrene‐b‐poly‐2‐vinylpyridine diblock copolymer melts are investigated with linear shear rheology and Fourier transformation rheology (FT rheology) to quantify their nonlinear behavior under oscillatory shear via mechanical higher harmonic contributions such as I3/1(ω1, γ0). The determination of the zero‐shear nonlinearity () by a variation of γ0 is hindered by the increasing domain alignment at increasing γ0. Thus, an approach for determining 3Q0(T) by a variation of the temperature is developed and used. This approach allows obtaining insights on the nonlinear behavior directly at temperature‐dependent phase transitions, such as at the order‐disorder transition temperature TODT of block copolymers. The maximum of 3Q0 is found to be close to TODT. The nonlinearity originating from the connection of the unequal polymer blocks is shown to dominate the overall nonlinearity, and the maximum of 3Q0(T) correlates to domain alignment for T < TODT.

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

Singh,

Chauhan,

Singh

2024

The Journal of Chemical Physics

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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, Pb, mimic the change in light intensity. The length scale follows power law growth, R(t) ∼ tϕ, where ϕ represents the growth exponent. Increasing Pb 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 Pb 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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Phase separation kinetics of block copolymer melts confined under moving parallel walls: A DPD study

Cited by 4 publications

References 79 publications

Evolution Kinetics of Stabilizing Pickering Emulsion by Brush-Modified Janus Particles: DPD Simulation and Experimental Insights

Evolution Kinetics of Stabilizing Pickering Emulsion by Brush-Modified Janus Particles: DPD Simulation and Experimental Insights

Nonlinear Melt Rheology of Lamellae Forming Polystyrene‐b‐Poly‐2‐Vinylpyridine Diblock Copolymers

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

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