Department of Polymer Materials and Chemical Engineering, School of Materials Science and Engineering, East China Jiaotong University, Nanchang 330013, P. R. China.
Soft Matter. 2017 Oct 18;13(40):7371-7380. doi: 10.1039/c7sm00916j.
Stimuli-responsive hydrogels using dynamic covalent bonds (DCBs) as cross-links may exhibit simultaneously the stimuli-responsibility of the physical gels and stability of the chemical gels. We prepared well-defined, ketone-based polymers based on commercially available diacetone acrylamide (DAAM) by a reversible addition-fragmentation chain transfer (RAFT) polymerization technique. The polymers could react with hexanedihydrazide yielding hydrogels. The mechanics, flexible properties and gelator concentration of the hydrogels can be tuned by varying the ratio of DAAM. Gelation time and hydrogel stability were gravely affected by the pH of the surrounding medium. The hydrogels possess self-healing ability without any external stimuli and undergo switchable sol-gel transition by the alternation of pH. In addition, the hydrogels showed pH-responsive controlled release behavior for rhodamine B. These kinds of ketone-type acylhydrazone DCB hydrogels, avoiding the aldehyde component, may ameliorate their biocompatibility and find potential applications in biomedicines, tissue engineering, etc.
使用动态共价键 (DCB) 作为交联剂的刺激响应水凝胶可能同时表现出物理凝胶的刺激响应性和化学凝胶的稳定性。我们通过可逆加成-断裂链转移 (RAFT) 聚合技术，以市售的二丙酮丙烯酰胺 (DAAM) 为原料，制备了基于酮的、结构明确的聚合物。聚合物可以与己二酰肼反应生成水凝胶。通过改变 DAAM 的比例，可以调节水凝胶的力学性能、柔韧性和凝胶剂浓度。凝胶化时间和水凝胶的稳定性受到周围介质 pH 值的严重影响。水凝胶具有无需外部刺激的自修复能力，并通过 pH 值的交替发生可切换的溶胶-凝胶转变。此外，水凝胶对罗丹明 B 表现出 pH 响应性控制释放行为。这种酮型酰腙 DCB 水凝胶，避免了醛组分，可能改善其生物相容性，并在生物医学、组织工程等领域有潜在的应用。
