CO₂-responsive hydrogels have attracted increasing and extensive attention from various fields such as sensors and controlled drug delivery systems. However, the traditional CO₂-responsive hydrogels suffer from unsatisfied responsive rate, which has limited their practical applications. Herein, we report on novel CO₂-responsive poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) hydrogels with fast responsive rate, which resulted from an open-celled porous structure inside the hydrogels. Oil-in-water emulsion templates prepared by microfluidic emulsification are used as porogens for synthesis of PDMAEMA hydrogels with open-celled porous structures. The open-celled porous structures provide numerous interconnected diffusion channels for the water transfer during the swelling process of PDMAEMA hydrogels. The effects of interconnectivity and size of pores on the CO₂-responsive rate of hydrogels are systematically investigated. The results show that the responsive rates of open-celled porous PDMAEMA hydrogels are much faster than that of the normal ones during the dynamic swelling processes. The open-celled hydrogels with large pore size exhibit the dramatic swelling after bubbling CO₂ for 20 s, and the maximum swelling rate is 30 times faster than that of normal hydrogels. The proposed new strategy for preparation of CO₂-responsive hydrogels with fast responsive rate may provide ever better performances for CO₂-responsive hydrogels in their myriad applications.

对CO ₂敏感的水凝胶已吸引了来自各个领域（例如传感器和受控药物输送系统）的越来越多的广泛关注。然而，传统的对CO ₂敏感的水凝胶具有不满意的敏感度，这限制了它们的实际应用。在此，我们报道了新型的CO ₂响应聚（N，N甲基丙烯酸-甲基丙烯酸二甲氨基乙酯（PDMAEMA）具有快速响应速率的水凝胶，这是由水凝胶内部的开孔多孔结构导致的。通过微流体乳化制备的水包油乳剂模板用作合成具有开孔多孔结构的PDMAEMA水凝胶的致孔剂。开孔的多孔结构为PDMAEMA水凝胶的溶胀过程中的水转移提供了许多相互连接的扩散通道。连通性和孔尺寸对CO _2的影响系统地研究了水凝胶的响应速度。结果表明，在动态溶胀过程中，开孔多孔PDMAEMA水凝胶的响应速度比正常水凝胶快得多。孔径大的开孔水凝胶在CO ₂鼓泡20 s后表现出明显的溶胀，最大溶胀速率比普通水凝胶快30倍。提出的用于制备具有快速响应速率的CO ₂响应水凝胶的新策略可能为无数应用中的CO ₂响应水凝胶提供更好的性能。