Yang Jinghao, Wen Hao, Zhuo Haitao, Chen Shaojun, Ban Jianfeng
Guangdong Research Center for Interfacial Engineering of Functional Materials, Shenzhen Key Laboratory of Polymer Science and Technology, Nanshan District Key Lab for Biopolymers and Safety Evaluation, College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China.
Shenzhen Key Laboratory of Functional Polymer, College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
Polymers (Basel). 2017 Jul 19;9(7):287. doi: 10.3390/polym9070287.
In this paper, we developed a photo-thermo staged-responsive shape-memory polymer network which has a unique ability of being spontaneously photo-responsive deformable and thermo-responsive shape recovery. This new type of shape-memory polyurethane network (A-SMPUs) was successfully synthesized with 4,4-azodibenzoic acid (Azoa), hexamethylenediisocyanate (HDI) and polycaprolactone (PCL), followed by chemical cross-linking with glycerol (Gl). The structures, morphology, and shape-memory properties of A-SMPUs have been carefully investigated. The results demonstrate that the A-SMPUs form micro-phase separation structures consisting of a semi-crystallized PCL soft phase and an Azoa amorphous hard phase that could influence the crystallinity of PCL soft phases. The chemical cross-linking provided a stable network and good thermal stability to the A-SMPUs. All A-SMPUs exhibited good triple-shape-memory properties with higher than 97% shape fixity ratio and 95% shape recovery ratio. Additionally, the A-SMPUs with higher Azoa content exhibited interesting photo-thermo two-staged responsiveness. A pre-processed film with orientated Azoa structure exhibited spontaneous curling deformation upon exposing to ultraviolet (UV) light, and curling deformation is constant even under Vis light. Finally, the curling deformation can spontaneously recover to the original shape by applying a thermal stimulus. This work demonstrates new synergistically multi-responsive SMPUs that will have many applications in smart science and technology.
在本文中，我们开发了一种光热分级响应形状记忆聚合物网络，它具有独特的自发光响应变形和热响应形状恢复能力。这种新型形状记忆聚氨酯网络（A-SMPUs）是通过4,4-偶氮二苯甲酸（Azoa）、六亚甲基二异氰酸酯（HDI）和聚己内酯（PCL）成功合成的，随后与甘油（Gl）进行化学交联。我们仔细研究了A-SMPUs的结构、形态和形状记忆性能。结果表明，A-SMPUs形成了由半结晶的PCL软相和Azoa非晶硬相组成的微相分离结构，这可能会影响PCL软相的结晶度。化学交联为A-SMPUs提供了稳定的网络和良好的热稳定性。所有A-SMPUs都表现出良好的三重形状记忆性能，形状固定率高于97%，形状恢复率高于95%。此外，具有较高Azoa含量的A-SMPUs表现出有趣的光热两级响应性。具有取向Azoa结构的预处理薄膜在暴露于紫外光（UV）时会自发卷曲变形，即使在可见光下卷曲变形也保持不变。最后，通过施加热刺激，卷曲变形可以自发恢复到原始形状。这项工作展示了新型的协同多响应SMPUs，它们将在智能科学技术中有许多应用。
