Controlling Degradation and Erosion of Polymer Networks: Insights from Mesoscale Modeling

Palkar, Vaibhav; Kuksenok, Olga

doi:10.1021/acs.jpcb.1c09570

Cited by 14 publications

(32 citation statements)

References 88 publications

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“…To characterize the degradation process, we first define a cluster as a set of bonded precursors at any stage during the degradation. 49 In a similar manner, we define the nanogel as the largest cluster of bonded precursors at a given time instant. This definition is relevant until the reverse gel point since only until this point, the largest cluster represents the remnant part of the original nanogel, as can be seen in Figure S1.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…For the bonded beads, an additional force is introduced in eq corresponding to the harmonic potential, U normalb normalo normaln normald = K normalb 2 ( r i j − r b ) 2 , where we set K b = 10 3 as a spring constant and r b = 0.7 as an equilibrium bond distance. To prevent unphysical crossing of polymer chains, we also adopted mSRP DPD formulation.…”

Section: Methodsmentioning

confidence: 99%

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Nanogel Degradation at Soft Interfaces and in Bulk: Tracking Shape Changes and Interfacial Spreading

2023

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Via mesoscale simulations, we characterize the process of controlled degradation of nanogels suspended in a single solvent and those adsorbed at the liquid−liquid interface between two incompatible fluids. Controlled degradation is of interest since it can be used to dynamically tailor size, shape, and transport properties of these soft particles. For the nanogels adsorbed at the liquid−liquid interfaces, controlled degradation can provide a means to dynamically tailor interfacial properties on the nanoscale. To characterize the degradation process, we track the structural characteristics of the remnant nanogel, such as its radius of gyration and shape anisotropy, and spatiotemporal distribution of the broken-off fragments. We use the dissipative particle dynamics approach with an adapted form of the modified segmental repulsive potential. We identify the reverse gel point and characterize the scaling of this point with the finite number of polymer precursors in the system. Furthermore, we characterize the effects of polymer−solvent interactions on the evolution of shape and effective size of the nanogel during the degradation process. We show that for the nanogel adsorbed onto the liquid−liquid interface, the extent of spreading is controlled by the relative extent of degradation. We demonstrate that depending on the properties of the soft interface, broken-off fragments can either disperse into one of the phases or adsorb onto the interface, enhancing the interfacial coverage and controlling interfacial properties on the nanoscale. Our study provides insights into using controlled degradation to dynamically tune shapes of nanocarriers and nanoscale topography at the liquid−liquid interfaces.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Nanogel Degradation at Soft Interfaces and in Bulk: Tracking Shape Changes and Interfacial Spreading

2023

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“…The parameters defining mSRP interactions are set as [101] b = 80 and d c = 0.8. These mSRP parameters were shown to effectively minimize topology violations in the original publication [101] and in the subsequent studies [105]. For the repulsion parameter between the same type of beads, we choose a ii = 78 in reduced DPD units, this value is calculated to reproduce water compressibility and corresponds to a single bead representing three water molecules [99].…”

Section: Methodsmentioning

confidence: 99%

Mesoscale Modeling of Agglomeration of Molecular Bottlebrushes: Focus on Conformations and Clustering Criteria

Choudhury

Giltner

et al. 2022

Polymers

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Using dissipative particle dynamics, we characterize dynamics of aggregation of molecular bottlebrushes in solvents of various qualities by tracking the number of clusters, the size of the largest cluster, and an average aggregation number. We focus on a low volume fraction of bottlebrushes in a range of solvents and probe three different cutoff criteria to identify bottlebrushes belonging to the same cluster. We demonstrate that the cutoff criteria which depend on both the coordination number and the length of the side chain allows one to correlate the agglomeration status with the structural characteristics of bottlebrushes in solvents of various qualities. We characterize conformational changes of the bottlebrush within the agglomerates with respect to those of an isolated bottlebrush in the same solvents. The characterization of bottlebrush conformations within the agglomerates is an important step in understanding the relationship between the bottlebrush architecture and material properties. An analysis of three distinct cutoff criteria to identify bottlebrushes belonging to the same cluster introduces a framework to identify both short-lived transient and long-lived agglomerates; the same approach could be further extended to characterize agglomerates of various macromolecules with complex architectures beyond the specific bottlebrush architecture considered herein.

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“…Within the mSRP formulation, an additional repulsive force F ij SRP = b (1 – d ij / d c ) e ij S is applied between the centers of the bonds if the distance between these centers, d ij = | d ij |, is below the cutoff distance d c ; herein, e ij S = d ij / d ij . Then, K b = 500, r b = 0.7, and mSRP parameters as b = 80 and d c = 0.8; these mSRP parameters were previously shown to effectively reduce topology violations. , Remaining parameters are chosen as follows: the beads number density is ρ = 3, the mass is m = 1, the cutoff radius is r c = 1, and the strengths of the dissipative and random forces are chosen to satisfy fluctuation-dissipation theorem , as γ = 4.5 and σ = 3.0. The parameters above and all of the simulation values below are provided in reduced DPD units.…”

Section: Methodsmentioning

confidence: 99%

“…Then, K b = 500, r b = 0.7, and mSRP parameters as b = 80 and d c = 0.8; these mSRP parameters were previously shown to effectively reduce topology violations. 42,43 Remaining parameters are chosen as follows: 32 the beads number density is ρ = 3, the mass is m = 1, the cutoff radius is r c = 1, and the strengths of the dissipative and random forces are chosen to satisfy fluctuation-dissipation theorem 32,34 as γ = 4.5 and σ = 3.0. The parameters above and all of the simulation values below are provided in reduced DPD units.…”

Section: Xf-np/pfoa Distribution Analysis Viamentioning

confidence: 99%

Effect of Fluorophobic Character upon Switching Nanoparticles in Polymer Films from Aggregated to Dispersed States Using Immersion Annealing

Zhang

Larison

et al. 2022

ACS Appl. Polym. Mater.

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For nanoparticle (NP) polymer composites, the state of dispersion vs aggregation significantly affects optical, electronic, thermal, and mechanical properties. The switching of NP distribution states thus far was limited to polymer solutions or bulky polymer-grafted NPs. Herein, for the first time, NP distribution states within polymer films are switched by adjusting fluorophobic interactions and the enthalpy of mixing with immersion annealing. The fluorophobic effect is the tendency of fluorinated molecules to strongly phase-separate from non/less fluorinated molecules. A highly fluorophobic homopolymer, poly(perfluorooctyl acrylate) (PFOA), was combined with gold NPs of variable fluorophobic character, prepared using mixtures of small-molecule ligands (xF-NP, where x is the mol % fluorinated ligands). Low-to-moderately fluorophobic F-NPs with PFOA were aggregated after spin coating where film swelling via immersion annealing with moderately fluorophobic trifluoro toluene (TFT) generally led to a dispersed state. In contrast, the highly fluorophobic 100F-NPs were dispersed regardless of immersion annealing. This behavior was attributed to the PFOA acting like a surfactant to enable dispersion of highly fluorophobic NPs in TFT. Since these two distinct behaviors favor nonoverlapping ranges of xF-NP compositions, the NPs with intermediate compositions exhibited limited dispersibility. This fluorophobic switchability could enable time- and chemical-selective sensing of fluorinated compounds in the future.

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Controlling Degradation and Erosion of Polymer Networks: Insights from Mesoscale Modeling

Cited by 14 publications

References 88 publications

Nanogel Degradation at Soft Interfaces and in Bulk: Tracking Shape Changes and Interfacial Spreading

Nanogel Degradation at Soft Interfaces and in Bulk: Tracking Shape Changes and Interfacial Spreading

Mesoscale Modeling of Agglomeration of Molecular Bottlebrushes: Focus on Conformations and Clustering Criteria

Effect of Fluorophobic Character upon Switching Nanoparticles in Polymer Films from Aggregated to Dispersed States Using Immersion Annealing

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