U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

PUBLICATIONS

Connecting Molecular Exchange Dynamics to Stress Relaxation in Phase-Separated Dynamic Covalent Networks

Published

Author(s)

Neil Dolinski, Ran Tao, Nicholas Boynton, Anthony Kotula, Charlie Lindberg, Kyle Petersen, Aaron M. Forster, Stuart Rowan

Abstract

A suite of phase separated dynamic covalent networks based on highly tunable dynamic benzalcyanoacetate (BCA) thia-Michael acceptors are investigated. In situ kinetic studies on small molecule model systems are used in conjunction with macroscopic characterization of phase stability and stress relaxation to understand how the molecular dynamics relate to relaxation modes. Electronic modification of the BCA unit strongly impacts the exchange dynamics (particularly the rate of dissociation) and the overall equilibrium constant (Keq) of the system, with electron-withdrawing groups leading to decreased dissociation rate and increased Keq. Critically, below a chemistry-defined temperature cutoff (related to the stability of the hard phase domains), the stress relaxation behavior of these phase separated materials is dominated by the molecular exchange dynamics, allowing for networks with a tailored thermomechanical response.
Citation
ACS Macro Letters
Volume
13
Pub Type
Journals

Download Paper

https://doi.org/10.1021/acsmacrolett.3c00717
Local Download

Keywords

dynamic covalent chemistry, exchange kinetics, stress relaxation, phase separation
Thermochemical properties, Polymers, Materials characterization, Materials and Composites

Citation

Dolinski, N. , Tao, R. , Boynton, N. , Kotula, A. , Lindberg, C. , Petersen, K. , Forster, A. and Rowan, S. (2024), Connecting Molecular Exchange Dynamics to Stress Relaxation in Phase-Separated Dynamic Covalent Networks, ACS Macro Letters, [online], https://doi.org/10.1021/acsmacrolett.3c00717, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956894 (Accessed April 27, 2024)

Created January 22, 2024, Updated January 24, 2024