Highly Deformable and Strongly Magnetic Semi-Interpenetrating Hydrogels Based on Alginate or Cellulose

The effective implementation of many of the applications of magnetic hydrogels requires the development of innovative systems capable of withstanding a substantial load of magnetic particles to ensure exceptional responsiveness, without compromising their reliability and stability under operational conditions. To address this challenge, double-network hydrogels have emerged as a promising foundation, thanks to their extraordinary mechanical deformability and toughness. Here, we report a semi-interpenetrating polymer networks (SIPNs) approach to create diverse magnetic SIPNs hydrogels based on alginate or cellulose, exhibiting remarkable deformability under certain stresses. Achieving strong responsiveness to magnetic fields is a key objective, and this characteristic is realized by the incorporation of highly magnetic iron microparticles at moderately large concentrations into the polymer network. Remarkably, the SIPNs hydrogels developed in this research accommodate high loadings of magnetic particles without significantly compromising their physical properties. This feature is essential for their use in applications that demand robust responsiveness to applied magnetic fields and overall stability, such as a hydrogel luminescent oxygen sensor controlled by magnetic fields that we designed and tested as proof-of-concept. These findings underscore the potential and versatility of magnetic SIPNs hydrogels based on carbohydrate biopolymers as fundamental components in driving the progress of advanced hydrogels for diverse practical implementations.磁性水凝胶（magnetic hydrogels）的诸多应用若要实现有效落地，需开发创新型体系，该体系可承受高负载量的磁性粒子，以保障优异的响应性能，同时不损害其在工作工况下的可靠性与稳定性。为应对这一挑战，双网络水凝胶凭借其卓越的机械变形能力与韧性，成为极具潜力的研究基础。本研究提出一种半互穿聚合物网络（semi-interpenetrating polymer networks, SIPNs）制备策略，用以构建基于藻酸盐（alginate）或纤维素（cellulose）的多样化磁性SIPNs水凝胶，该类水凝胶在特定应力下展现出优异的变形性能。实现对磁场的强响应是核心研发目标，这一特性可通过将高磁性铁微米颗粒以适中较高浓度掺入聚合物网络中得以实现。值得注意的是，本研究开发的SIPNs水凝胶可承载高负载量的磁性粒子，且不会显著劣化其物理性能。这一特性对于其应用于需要强磁场响应与整体稳定性的场景至关重要，例如我们设计并完成概念验证的磁场调控水凝胶发光氧传感器。本研究结果凸显了基于糖类生物聚合物的磁性SIPNs水凝胶的应用潜力与多功能性，其可作为核心组分推动先进水凝胶技术的发展，适配多样化的实际应用场景。