Poly(N‐isopropylacrylamide) Nanoparticle‐Incorporated PNIPAAm Hydrogels with Fast Shrinking Kinetics

Summary: Novel temperature‐responsive poly( N ‐isopropylacrylamide) (PNIPAAm) nanoparticle‐containing PNIPAAm hydrogels were prepared by radical polymerization. In comparison with conventional PNIPAAm hydrogels, the PNIPAAm gels thus prepared exhibit much faster response rates as the temperature is raised above the lower critical solution temperature. The improved properties are a result of the incorporation of PNIPAAm particles, which first shrink and then generate pores for water molecules to be quickly squeezed out of the bulky PNIPAAm gels. Schematic illustration of the shrinking process: (I) First PNIPAAm particles shrink and generate pores; (II) the bulky gels then shrink further at a rapid rate. image Schematic illustration of the shrinking process: (I) First PNIPAAm particles shrink and generate pores; (II) the bulky gels then shrink further at a rapid rate.