Micro-scale structural polymer membranes with desired mechanical properties, such as modulus and stretchability, have extensive applications in repair scaffolds, stretchable electronic devices, etc., yet how to achieve the simultaneous tunability of high modulus (MPa-level) and excellent resilience in micron-scale polymer membrane remains challenge. In this work, based on the material-structure integrated design aided by mechanical modeling and photolithograph, a micro-scale-structured solid-state lithography polyurethane-urea (UVSLPU) membrane has been fabricated, achieving a wide range of controllability on elastic modulus of 25–55 MPa and stretchability of 2.7–7.6 by simultaneously controlling the exposure time and area. Based on the physical mechanism of solid-state lithography, a novel visco-hyperelastic constitutive model is developed to facilitate the quantitative tunning of the mechanical property of UVSLPU. According to the microstructure analysis, the model decomposes the free energy of UVSLPU into three components, including crosslinked network, free chains as well as dangling chains, and describes the influence of exposure time on their nonlinear evolutions through increasing chain density and reducing the number of Kuhn monomers per chain. The proposed model is validated through uniaxial tensile tests conducted at different strain rates and exposure conditions, and reveals the significant contribution of crosslinks and free chains in enhancing the modulus over exposure time. Then, by integrating constitutive modeling and spatiotemporal controllable photolithograph, the design and manufacture for the micro-scale-structured UVSLPU membrane achieving increasing stiffness without losing the stretchability is realized by precisely controlling the exposure area. This work offers a novel and efficient approach for the design and manufacture of micro-scale-structured membranes with desired mechanical properties.

中文翻译：

---

通过集成力学建模和时空可控光刻，同时调节微尺度结构聚合物膜的刚度和可拉伸性


具有所需机械性能（如模量和可拉伸性）的微尺度结构聚合物膜在修复支架、可拉伸电子设备等方面有广泛的应用，但如何在微米级聚合物膜中同时实现高模量可调性（MPa 级）和出色的回弹性仍然是一个挑战。在这项工作中，基于机械建模和光刻辅助的材料-结构一体化设计，制造了一种微尺度结构的固态光刻聚氨酯-尿素 （UVSLPU） 膜，通过同时控制曝光时间和面积，实现了 25-55 MPa 的宽弹性模量可控性和 2.7-7.6 的拉伸性。基于固态光刻的物理机理，开发了一种新的粘超弹性本构模型，以促进 UVSLPU 力学性能的定量调整。根据微观结构分析，该模型将 UVSLPU 的自由能分解为交联网络、自由链和悬链 3 部分，并通过增加链密度和减少每条链的 Kuhn 单体数量来描述暴露时间对其非线性演化的影响。通过在不同应变速率和暴露条件下进行的单轴拉伸测试验证了所提出的模型，并揭示了交联和自由链在提高暴露时间模量方面的显着贡献。然后，通过整合本构建模和时空可控光刻，通过精确控制曝光面积，实现了微尺度结构 UVSLPU 膜的设计与制造，在不损失拉伸性的情况下实现增加刚度。 这项工作为设计和制造具有所需机械性能的微尺度结构膜提供了一种新颖而有效的方法。