Responsive Hybrid Poly(vinyl alcohol) Hydrogel Membranes with Embedded Microgels as Valves

The research and application of responsive materials have long been hampered by their complicated designs and tedious construction processes. Besides, many current responsive materials show retard or weak responsiveness. In this study, responsive hybrid poly(vinyl alcohol) hydrogel membranes with embedded poly( N -isopropylacrylamide-acrylic acid) microgels as valves were constructed by simple mixing and subsequent freezing-thawing process. In the structure of the membranes, the matrix poly(vinyl alcohol) chains thread through and entangle with the microgels, and the microgels are firmly constrained within the hybrid hydrogel network. The fast and sharp temperature responsiveness of the embedded microgels was largely retained and endowed the hydrogel membrane with excellent temperature and pH responsiveness. Moreover, the hydrogel membrane showed excellent fatigue resistance in both temperature and pH-responsive flux examination. This study presented the great potential of these hybrid hydrogel membranes in biomedical applications and provided a new strategy for the future design and construction of responsive biomaterials.