Polymer architecture dictates multiple relaxation processes in soft networks with two orthogonal dynamic bonds

Area of Science:

• Polymer Chemistry
• Materials Science
• Rheology

Background:

• Tunable polymer networks are essential for advanced applications like self-healing and additive manufacturing.
• Predictively designing polymer networks with hierarchical relaxation processes remains a significant challenge due to complex influencing factors.

Purpose of the Study:

• To investigate how network connectivity and orthogonal dynamic bond exchange mechanisms govern the relaxation spectrum.
• To synthesize polymer networks with both pendant and telechelic architectures using mixed orthogonal dynamic bonds.

Main Methods:

• Synthesis of polymer networks incorporating both hydrogen-bonding groups and vitrimeric dynamic crosslinkers.
• Characterization of multimodal relaxation behavior in pendant and telechelic network architectures.
• Analysis of the impact of orthogonal dynamic bonds on network dynamics and mechanical properties.

Main Results:

• Multimodal relaxation was observed in both pendant and telechelic networks synthesized with mixed orthogonal dynamic bonds.
• The incorporation of orthogonal dynamic bonds led to improved damping and enhanced mechanical properties.
• Two distinct relaxation processes were identified, originating from hydrogen-bond exchange and retained in the mixed dynamic networks.

Conclusions:

• This study provides molecular insights into the predictive design of hierarchical dynamics in soft materials.
• Orthogonal dynamic bonds offer a pathway to precisely control viscoelastic properties and enhance material performance.
• The findings facilitate the development of advanced polymers for demanding applications requiring tunable mechanical responses.