Du Mengqi, Li Chuang
Key Laboratory of Precision and Intelligent Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, 230026, China.
Adv Mater. 2024 Oct;36(40):e2408484. doi: 10.1002/adma.202408484. Epub 2024 Aug 27.
The integration of photoswitchable supramolecular units into hydrogels allows for spatiotemporal control over their nanoscale topological network and macroscale properties using light. Nevertheless, the current availability of photoswitchable supramolecular interactions for the development of such materials remains limited. Here, the molecular design of a novel photoswitchable cucurbit[8]uril-spiropyran host-guest complex exhibiting fast and reversible switching of binding ratios between 1:2 and 1:1 is reported. Photoswitchable complexation stoichiometries are rationally exploited as (de)crosslinking units in multiple polymers for the design of supramolecular hydrogels displaying highly dynamic and switchable features that are spatiotemporally controlled by light. The hydrogels exhibit rapid reversible mechanical softening-hardening upon alternating irradiation with blue and UV light, which is used to significantly accelerate and improve the efficiency of self-healing and shape-remolding of hydrogels. Furthermore, spiropyran endows such materials with unique reversible photochromic properties for reproducible patterning/erasing and information storage. Using a dual-light-assisted extrusion process, meter-scale hydrogel fibers with enhanced structural integrity and photoswitchable ionic conductivity are constructed and woven into various slidable knots and fluorescent shapes. This work represents an innovative molecular design strategy for advancing the development of spatiotemporally engineered supramolecular hydrogels using light and opens avenues for their prospective applications in dynamic materials and adaptive systems.
将可光开关的超分子单元整合到水凝胶中，能够利用光对其纳米级拓扑网络和宏观性质进行时空控制。然而，目前可用于开发此类材料的可光开关超分子相互作用仍然有限。在此，报道了一种新型可光开关的葫芦[8]脲 - 螺吡喃主客体复合物的分子设计，该复合物在1:2和1:1之间表现出快速且可逆的结合比切换。可光开关的络合化学计量被合理地用作多种聚合物中的（去）交联单元，用于设计具有高度动态和可切换特性的超分子水凝胶，这些特性可通过光进行时空控制。该水凝胶在交替照射蓝光和紫外光时表现出快速可逆的机械软化 - 硬化，这被用于显著加速和提高水凝胶的自愈和形状重塑效率。此外，螺吡喃赋予此类材料独特的可逆光致变色特性，用于可重复的图案化/擦除和信息存储。使用双光辅助挤出工艺，构建了具有增强结构完整性和可光开关离子导电性的米级水凝胶纤维，并将其编织成各种可滑动的结和荧光形状。这项工作代表了一种创新的分子设计策略，用于推进利用光进行时空工程的超分子水凝胶的开发，并为其在动态材料和自适应系统中的潜在应用开辟了道路。
