Publisher’s Note: Molecular Dynamics Simulations of Polymer Welding: Strength from Interfacial Entanglements [Phys. Rev. Lett.<b>110</b>, 098301 (2013)]

Ge, Ting; Pierce, Flint; Perahia, Dvora; Grest, Gary S.; Robbins, Mark O.

doi:10.1103/physrevlett.110.129902

Cited by 7 publications

(36 citation statements)

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“…To limit excluded volume effects, we use a modification of the original PPA algorithm where the diameter of repulsive interactions between chains is then reduced by a factor of four and the contour is minimized again. 6,18,45 The resulting configuration is a network of primitive paths for each chain.…”

Section: Simulation Model and Methodologymentioning

confidence: 99%

“…6. They show that at t c the interfacial entanglement density is still strongly suppressed from the bulk value for chains with N = 500.…”

Section: Correlating Failure Mechanisms To Entanglementsmentioning

confidence: 99%

“…[4][5][6][8][9][10][11][12][13][14][15][16][17][18] Experiments 4,8,9 have found a correlation between the mechanical strength and the interfacial width. For homopolymers, the growth of interfacial width with time has been explained using reptation theory.…”

Section: Introductionmentioning

confidence: 97%

“…This saturation occurs at the same time as the saturation of shear strength. 6 While σ max only increases by a factor of 2 or 3 during welding, G I increases by more than two orders of magnitude because of the large increase in craze volume. As in studies of shear strength, 18 interfaces between immiscible polymers are weaker because their finite equilibrium width suppresses entanglements.…”

Section: Introductionmentioning

confidence: 97%

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Tensile Fracture of Welded Polymer Interfaces: Miscibility, Entanglements, and Crazing

Grest

Robbins

2014

Macromolecules

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Large-scale molecular simulations are performed to investigate tensile failure of polymer interfaces as a function of welding time t. Changes in the tensile stress, mode of failure and interfacial fracture energy G I are correlated to changes in the interfacial entanglements as determined from Primitive Path Analysis. Bulk polymers fail through craze formation, followed by craze breakdown through chain scission. At small t welded interfaces are not strong enough to support craze formation and fail at small strains through chain pullout at the interface. Once chains have formed an average of about one entanglement across the interface, a stable craze is formed throughout the sample. The failure stress of the craze rises with welding time and the mode of craze breakdown changes from chain pullout to chain scission as the interface approaches bulk strength. The interfacial fracture energy G I is calculated by coupling the simulation results to a continuum fracture mechanics model. As in experiment, G I increases as * To whom correspondence should be addressed † Johns Hopkins University ‡ University of North Carolina ¶ Sandia National Laboratories 1 arXiv:1410.1917v1 [cond-mat.soft] 7 Oct 2014 t 1/2 before saturating at the average bulk fracture energy G b . As in previous simulations of shear strength, saturation coincides with the recovery of the bulk entanglement density. Before saturation, G I is proportional to the areal density of interfacial entanglements. Immiscibiltiy limits interdiffusion and thus suppresses entanglements at the interface. Even small degrees of immisciblity reduce interfacial entanglements enough that failure occurs by chain pullout and

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Section: Simulation Model and Methodologymentioning

confidence: 99%

“…6. They show that at t c the interfacial entanglement density is still strongly suppressed from the bulk value for chains with N = 500.…”

Section: Correlating Failure Mechanisms To Entanglementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

Tensile Fracture of Welded Polymer Interfaces: Miscibility, Entanglements, and Crazing

Grest

Robbins

2014

Macromolecules

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“…Since our goal is to address generic behavior, we use a simple model potential that captures many aspects of the behavior of hydrocarbon chains [68][69][70][71][72][73]. Fluid molecules are modeled as short linear chains of four spherical beads.…”

Section: Simulation Methodsmentioning

confidence: 99%

Capillary adhesion at the nanometer scale

Cheng

Robbins

2014

Phys. Rev. E

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Molecular dynamics simulations are used to study the capillary adhesion from a nonvolatile liquid meniscus between a spherical tip and a flat substrate. The atomic structure of the tip, the tip radius, the contact angles of the liquid on the two surfaces, and the volume of the liquid bridge are varied. The capillary force between the tip and substrate is calculated as a function of their separation h. The force agrees with continuum predictions based on macroscopic theory for h down to ∼5 to 10 nm. At smaller h, the force tends to be less attractive than predicted and has strong oscillations. This oscillatory component of the capillary force is completely missed in the macroscopic theory, which only includes contributions from the surface tension around the circumference of the meniscus and the pressure difference over the cross section of the meniscus. The oscillation is found to be due to molecular layering of the liquid confined in the narrow gap between the tip and substrate. This effect is most pronounced for large tip radii and/or smooth surfaces. The other two components considered by the macroscopic theory are also identified. The surface tension term, as well as the meniscus shape, is accurately described by the macroscopic theory for h down to ∼1 nm, but the capillary pressure term is always more positive than the corresponding continuum result. This shift in the capillary pressure reduces the average adhesion by a factor as large as 2 from its continuum value and is found to be due to an anisotropy in the pressure tensor. The component in the plane of the substrate is consistent with the capillary pressure predicted by the macroscopic theory (i.e., the Young-Laplace equation), but the normal pressure that determines the capillary force is always more positive than the continuum counterpart.

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Next‐Generation Vitrimers Design through Theoretical Understanding and Computational Simulations

Li,

Tran,

Pan

et al. 2023

Advanced Science

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Vitrimers are an innovative class of polymers that boast a remarkable fusion of mechanical and dynamic features, complemented by the added benefit of end‐of‐life recyclability. This extraordinary blend of properties makes them highly attractive for a variety of applications, such as the automotive sector, soft robotics, and the aerospace industry. At their core, vitrimer materials consist of crosslinked covalent networks that have the ability to dynamically reorganize in response to external factors, including temperature changes, pressure variations, or shifts in pH levels. In this review, the aim is to delve into the latest advancements in the theoretical understanding and computational design of vitrimers. The review begins by offering an overview of the fundamental principles that underlie the behavior of these materials, encompassing their structures, dynamic behavior, and reaction mechanisms. Subsequently, recent progress in the computational design of vitrimers is explored, with a focus on the employment of molecular dynamics (MD)/Monte Carlo (MC) simulations and density functional theory (DFT) calculations. Last, the existing challenges and prospective directions for this field are critically analyzed, emphasizing the necessity for additional theoretical and computational advancements, coupled with experimental validation.

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Publisher’s Note: Molecular Dynamics Simulations of Polymer Welding: Strength from Interfacial Entanglements [Phys. Rev. Lett.110, 098301 (2013)]

Cited by 7 publications

References 0 publications

Tensile Fracture of Welded Polymer Interfaces: Miscibility, Entanglements, and Crazing

Tensile Fracture of Welded Polymer Interfaces: Miscibility, Entanglements, and Crazing

Capillary adhesion at the nanometer scale

Next‐Generation Vitrimers Design through Theoretical Understanding and Computational Simulations

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