Rheological and structural properties of associated polymer networks studied <i>via</i> non-equilibrium molecular dynamics simulation

Peng, Yuankun; Yue, Tongkui; Li, Sai; Gao, Ke; Wang, Yachen; Li, Ziwei; Ye, Xin; Zhang, Liqun; Li, Jun

doi:10.1039/d1me00017a

Cited by 7 publications

(7 citation statements)

References 32 publications

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“…Therefore, the shear viscosity as a function of shear rate is obtained using reverse nonequilibrium molecular dynamics simulation, from which the corresponding η 0 is available (as shown in Figure S2). It has been demonstrated in our previous work that this method of calculating viscosity is reasonable . We obtain a reliable viscosity value η 0 = 47.5 for the bottlebrush polymer system we established.…”

Section: Resultssupporting

confidence: 59%

“…It has been demonstrated in our previous work that this method of calculating viscosity is reasonable. 49 We obtain a reliable viscosity value η 0 = 47.5 for the bottlebrush polymer system we established. Based on eq 7, we calculate the predicted values of the SE equation that are compared with the diffusion coefficients obtained from MD simulations, as shown in Figure 4b.…”

Section: Dispersion Of Snps and Nrsmentioning

confidence: 72%

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Dispersion and Diffusion Mechanism of Nanofillers with Different Geometries in Bottlebrush Polymers: Insights from Molecular Dynamics Simulation

Chen

Huang

et al. 2022

J. Phys. Chem. B

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The dispersion and diffusion mechanism of nanofillers in polymer nanocomposites (PNCs) are crucial for understanding the properties of PNCs, which is of great significance for the design of novel materials. Herein, we investigate the dispersion and diffusion behavior of two geometries of nanofillers, namely, spherical nanoparticles (SNPs) and nanorods (NRs), in bottlebrush polymers by utilizing coarse-grained molecular dynamics simulations. With the increase of the interaction strength between the nanofiller and polymer (εnp), both the SNPs and NRs experience a typical “aggregated phase–dispersed phase–bridged phase” state transition in the bottlebrush polymer matrix. We evaluate the validity of the Stokes–Einstein (SE) equation for predicting the diffusion coefficient of nanofillers in bottlebrush polymers. The results demonstrate that the SE predictions are slightly larger than the simulated values for small SNP sizes because the local viscosity that is felt by small SNPs in the densely grafted bottlebrush polymer does not differ much from the macroscopic viscosity. The relative size of the length of the NRs (L) and the radius of gyration (R g) of the bottlebrush polymer play a key role in the diffusion of NRs. In addition, we characterize the anisotropic diffusion of NRs to analyze their translational and rotational diffusion. The motion of NRs in the direction perpendicular to the end-to-end vector is more hindered, indicating that there is a strong coupling between the rotation of NRs and the motion of the polymer. The NR motion shows stronger anisotropic diffusion at short time scales because of the steric effects generated by side chains of the bottlebrush polymer. In general, our results provide a fundamental understanding of the dispersion of nanofillers and the microscopic mechanism of nanofiller diffusion in bottlebrush polymers.

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Section: Resultssupporting

confidence: 59%

Section: Dispersion Of Snps and Nrsmentioning

confidence: 72%

Dispersion and Diffusion Mechanism of Nanofillers with Different Geometries in Bottlebrush Polymers: Insights from Molecular Dynamics Simulation

Chen

Huang

et al. 2022

J. Phys. Chem. B

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“…The viscosity of a non-Newtonian fluid decreases with increasing shear rate before reaching a critical shear rate, and this rheological behavior is known as shear thinning. Yuankun Peng et al 41 and Eihab Jaber et al 42 successfully characterized the relationship between shear thinning and chain orientation of polymers in NEMD simulations by calculating the polymer chain orientation, where shear action causes chain ordering and orientation changes, leading to physical network breakage. In this paper, we will use polymer chain orientation theory to describe the evolution of shear thinning behavior and microstructure of non-Newtonian fluids.…”

Section: Resultsmentioning

confidence: 99%

Microscopic mechanism study of the rheological behavior of non-Newtonian fluids based on dissipative particle dynamics

Wang

et al. 2023

Soft Matter

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“…The shear stress is also not proportional to the shear rate, exhibiting that the system is a non-Newtonian fluid. Combined with the variation of shear viscosity with shear rate (Figure G), the sample showed shear thinning behavior, corresponding to the wormlike micelle or polymers. , To obtain further information, the linear viscoelastic region of the system was determined by shear strain scanning (Figure S9), while oscillatory shear experiments were carried out on the sample with the shear strain (γ) fixed at 1% and frequencies of 0.01–1.00 Hz. The dynamic rheogram of 40.0 mmol/L aqueous solutions in the presence of Se-CQDs also infers the construction of “branched polymers”.…”

Section: Resultsmentioning

confidence: 99%

Phase Behavior and Aggregate Transition Based on Co-assembly of Negatively Charged Carbon Dots and a pH-Responsive Tertiary Amine Cationic Surfactant

Yin

Wang

et al. 2022

Langmuir

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We studied the co-assembly of an oppositely changed binary mixture of selenium-doped carbon quantum dots (Se-CQDs) and N,N-dimethyl octylamide-propyl tertiary amine (DOAPA) through turbidity, ζ potential measurement, and cryogenic transmission electron microscopy (cryo-TEM) with the aim of fabricating supramolecular assemblies with multiple dimensions and novel morphologies. The Se-CQD/DOAPA binary mixture exhibited abundant phase behavior, in which an isotropic phase (I 1 ) was first observed, followed by turbidity (T), precipitation (P), and a second isotropic phase (I 2 ), as the DOAPA concentration increased. Then we focused on investigating the morphologies of samples. In cryo-TEM observations, spherical aggregates were observed in all phase sequences, whereas the aggregates have different ζ potentials and sizes. In the I 2 phase, interesting nanocapsulelike aggregates and spindle-like aggregates can be identified in addition to spherical aggregates. In combination with the rheological behaviors of the I 2 phase solution and the detailed structure of the aggregates from enlarged cryo-TEM images, it is possible that the Se-CQDs and DOAPA co-assemble with novel network-like building blocks. The turbid solutions were found to be responsive to pH in phase P, and spherical aggregates were obtained at pH 6.5 but turned into vesicles when the pH reached 5.0. On the basis of these findings, CQDs and surfactants can be good structural building blocks for supramolecular structures, and the diverse morphologies of aggregates offer the prospect of multiple applications in the future.

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Rheological and structural properties of associated polymer networks studied via non-equilibrium molecular dynamics simulation

Abstract: An intensive understanding of the rheological and structural properties of polymer physical networks formed via the associative functional groups at the molecular level is still lacking. Herein, we employed coarse-grained...

Cited by 7 publications

References 32 publications

Dispersion and Diffusion Mechanism of Nanofillers with Different Geometries in Bottlebrush Polymers: Insights from Molecular Dynamics Simulation

Dispersion and Diffusion Mechanism of Nanofillers with Different Geometries in Bottlebrush Polymers: Insights from Molecular Dynamics Simulation

Microscopic mechanism study of the rheological behavior of non-Newtonian fluids based on dissipative particle dynamics

Phase Behavior and Aggregate Transition Based on Co-assembly of Negatively Charged Carbon Dots and a pH-Responsive Tertiary Amine Cationic Surfactant

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