Connecting Molecular Exchange Dynamics to Stress Relaxation in Phase-Separated Dynamic Covalent Networks
Connecting Molecular Exchange Dynamics to Stress Relaxation in Phase-Separated Dynamic Covalent Networks
复制标题
将分子交换动力学与相分离动态共价网络中的应力松弛联系起来
DOI：
10.1021/acsmacrolett.3c00717
复制
发表时间：
2024
影响因子：
7.015
通讯作者：
Rowan, Stuart J.
中科院分区：
文献类型：
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作者：
Dolinski, Neil D.;Tao, Ran;Boynton, Nicholas R.;Kotula, Anthony P.;Lindberg, Charlie A.;Petersen, Kyle J.;Forster, Aaron M.;Rowan, Stuart J.
研究了一系列基于高度可调动态苄叉氰基乙酸（BCA）硫杂迈克尔受体的相分离动态共价网络。小分子模型系统的原位动力学研究与相稳定性和应力松弛的宏观表征结合使用，以了解分子动力学与松弛模式的关系。BCA单元的电子修饰强烈影响交换动力学（特别是解离速率）和系统的总体平衡常数（Keq），吸电子基团导致解离速率降低和Keq增加。重要的是，低于化学定义的温度截止（与硬相域的稳定性相关），这些相分离材料的应力松弛行为由分子交换动力学主导，从而允许具有定制的热机械响应的网络。
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 increasedKeq. 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.