Copolymers, which are synthesized through the statistical arrangement of two comonomers with different side chains, provide a versatile platform for the design of tunable multi-shape memory materials. However, their inherent spatial heterogeneity poses a challenge in precisely controlling the thermomechanical properties and the multi-shape memory effect (multi-SME). In this study, we propose a cooperative thermodynamic model that incorporates the concept of phase transition into the Adam-Gibbs model to address this issue. The statistical distribution of the two comonomers in the backbone is characterized using the Gaussian distribution function. By extending the Fox equation, we investigate the significant impact of composition fluctuation on local activation, heterogeneous dynamics, and the glass transition range in multi-shape memory copolymers. Furthermore, we evaluate the effectiveness of our proposed model by predicting the thermomechanical behavior and shape memory performance in copolymers with dual-, triple-, and quadruple-SMEs. The numerical results indicate that the compositional heterogeneity and the synchronized cooperative motion result in broad glass transitions in copolymers with pendant groups. Additionally, it is found that the tunable multi-SME is strongly correlated with the heterogeneous activations of local cooperative rearrangement regions. The proposed model is expected to provide theoretical guidance for the practical application of multi-shape memory copolymers.

中文翻译：

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具有吊坠基团的共聚物中异质玻璃化转变与可调多形状记忆效应之间的内在相关性


共聚物是通过两种具有不同侧链的共聚单体的统计排列合成的，为可调多形状记忆材料的设计提供了一个多功能平台。然而，它们固有的空间异质性对精确控制热机械性能和多形状记忆效应 （multi-SME） 构成了挑战。在这项研究中，我们提出了一个合作热力学模型，该模型将相变的概念纳入 Adam-Gibbs 模型来解决这个问题。使用高斯分布函数表征骨架中两种共聚单体的统计分布。通过扩展 Fox 方程，我们研究了成分波动对多形状记忆共聚物中局部活化、异质动力学和玻璃化转变范围的显着影响。此外，我们通过预测具有双、三和四 SME 的共聚物中的热机械行为和形状记忆性能来评估我们提出的模型的有效性。数值结果表明，成分异质性和同步的协同运动导致具有吊基的共聚物中产生广泛的玻璃化转变。此外，研究发现可调谐的 multi-SME 与局部协作重排区域的异质激活密切相关。所提出的模型有望为多形状记忆共聚物的实际应用提供理论指导。