The role of structure in the nonlinear mechanics of cross-linked semiflexible polymer networks

Nicholas Agung Kurniawan; Søren Enemark; Raj Rajagopalan

doi:10.1063/1.3682779

The role of structure in the nonlinear mechanics of cross-linked semiflexible polymer networks

The Journal of Chemical Physics ◽

10.1063/1.3682779 ◽

2012 ◽

Vol 136 (6) ◽

pp. 065101 ◽

Cited By ~ 19

Author(s):

Nicholas Agung Kurniawan ◽

Søren Enemark ◽

Raj Rajagopalan

Keyword(s):

Polymer Networks ◽

Nonlinear Mechanics ◽

Semiflexible Polymer

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The role of stickiness in the rheology of semiflexible polymers

Soft Matter ◽

10.1039/c9sm00433e ◽

2019 ◽

Vol 15 (24) ◽

pp. 4865-4872 ◽

Cited By ~ 5

Author(s):

Tom Golde ◽

Martin Glaser ◽

Cary Tutmarc ◽

Iman Elbalasy ◽

Constantin Huster ◽

...

Keyword(s):

Rheological Properties ◽

Polymer Networks ◽

Semiflexible Polymers ◽

Semiflexible Polymer

The rheological properties of semiflexible polymer networks are strongly affected by a polymer specific stickiness.

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Increasing valence pushes DNA nanostar networks to the isostatic point

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1819683116 ◽

2019 ◽

Vol 116 (15) ◽

pp. 7238-7243 ◽

Cited By ~ 5

Author(s):

Nathaniel Conrad ◽

Tynan Kennedy ◽

Deborah K. Fygenson ◽

Omar A. Saleh

Keyword(s):

Shear Modulus ◽

Strain Hardening ◽

Polymer Networks ◽

Plateau Modulus ◽

Entropic Elasticity ◽

Semiflexible Polymer ◽

Rubber Model ◽

Series Of Experiments ◽

Nonlinear Elastic

The classic picture of soft material mechanics is that of rubber elasticity, in which material modulus is related to the entropic elasticity of flexible polymeric linkers. The rubber model, however, largely ignores the role of valence (i.e., the number of network chains emanating from a junction). Recent work predicts that valence, and particularly the Maxwell isostatic point, plays a key role in determining the mechanics of semiflexible polymer networks. Here, we report a series of experiments confirming the prominent role of valence in determining the mechanics of a model system. The system is based on DNA nanostars (DNAns): multiarmed, self-assembled nanostructures that form thermoreversible equilibrium gels through base pair-controlled cross-linking. We measure the linear and nonlinear elastic properties of these gels as a function of DNAns arm number, f, and concentration [DNAns]. We find that, as f increases from three to six, the gel’s high-frequency plateau modulus strongly increases, and its dependence on [DNAns] transitions from nonlinear to linear. Additionally, higher-valence gels exhibit less strain hardening, indicating that they have less configurational freedom. Minimal strain hardening and linear dependence of shear modulus on concentration at high f are consistent with predictions for isostatic systems. Evident strain hardening and nonlinear concentration dependence of shear modulus suggest that the low-f networks are subisostatic and have a transient, potentially fractal percolated structure. Overall, our observations indicate that network elasticity is sensitive both to entropic elasticity of network chains and to junction valence, with an apparent isostatic point 5<fc≤6 in agreement with the Maxwell prediction.

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Exploring secondary interactions and the role of temperature in moisture-contaminated polymer networks through molecular simulations

Soft Matter ◽

10.1039/d0sm02009e ◽

2021 ◽

Vol 17 (10) ◽

pp. 2942-2956

Author(s):

Rishabh D. Guha ◽

Ogheneovo Idolor ◽

Katherine Berkowitz ◽

Melissa Pasquinelli ◽

Landon R. Grace

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulations ◽

Temperature Variation ◽

Polymer Networks ◽

Molecular Simulations ◽

Effect Of Temperature ◽

Secondary Interactions ◽

Dynamics Simulations ◽

Secondary Bonding

We investigated the effect of temperature variation on the secondary bonding interactions between absorbed moisture and epoxies with different morphologies using molecular dynamics simulations.

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