Local dynamics and failure of inhomogeneous polymer networks

Area of Science:

• Polymer Science
• Materials Science
• Computational Materials Science

Background:

• Inhomogeneous crosslinked polymers offer tunable properties by combining complementary materials.
• Understanding the dynamics and failure mechanisms of rubbery/glassy conetworks is crucial for materials design.

Purpose of the Study:

• To investigate the influence of phase boundaries on local mobility in microphase-separated polymer networks.
• To explore the microscopic failure mechanisms in these networks under uniaxial extension.

Main Methods:

• Coarse-grained molecular dynamics simulations were employed to create bicontinuous rubbery/glassy polymer networks.
• The study analyzed the local mobility gradient across phase interfaces and simulated bond breaking during deformation.

Main Results:

• An asymmetric mobility gradient was observed across the phase boundary, extending deeper into the lower glass transition temperature (Tg) phase when the system temperature is between the two Tg values.
• Under uniaxial extension, stress initially concentrates in the glassy domain, followed by homogenization of segmental dynamics and subsequent bond breaking.

Conclusions:

• The findings provide insights into the structure-property relationships of inhomogeneous polymer networks.
• This research contributes to the predictive design of advanced polymer materials with enhanced mechanical performance and specific transport capabilities.