Biodegradable synthetic hydrogels have emerged as promising materials for tissue engineering and drug/cell delivery applications. However, their successful implementation requires precise understanding of the degradation response in terms of mechanical properties, swelling, and mass loss. In this work, we develop a thermodynamically-consistent continuum framework and constitutive models for coupled large deformation and hydrolytic degradation in hydrogels. In particular, we propose constitutive models for the evolution of elastic modulus and polymer mass loss based on a description of the evolving network topology during hydrolysis. The theory is validated against experimental data for two model hydrogel systems with different network architectures, namely biodegradable Tetra-PEG hydrogels and PLA-b-PEG-b-PLA hydrogels. We have also implemented our model in a finite element software. We show that our model is capable of simulating degradation-induced heterogeneous swelling in scenarios relevant to biomedical applications. Our theory and constitutive models could be useful for the design of hydrogels with controlled degradation behaviour.

可生物降解的合成水凝胶已成为组织工程和药物/细胞递送应用的有前途的材料。然而，它们的成功实施需要准确了解机械性能、膨胀和质量损失方面的降解响应。在这项工作中，我们开发了一种热力学一致的连续体框架和本构模型，用于水凝胶中耦合的大变形和水解降解。特别是，我们基于对水解过程中不断演变的网络拓扑结构的描述，提出了弹性模量和聚合物质量损失演变的本构模型。该理论针对具有不同网络架构的两种模型水凝胶系统的实验数据进行了验证，即可生物降解的 Tetra-PEG 水凝胶和 PLA-b-PEG-b-PLA 水凝胶。我们还在有限元软件中实现了我们的模型。我们表明，我们的模型能够在与生物医学应用相关的场景中模拟降解引起的异质肿胀。我们的理论和本构模型可用于设计具有可控降解行为的水凝胶。