CHAPTER 5: Stimuli-Responsive Cationic Microgels and Hydrogels Based on Poly(N,N-dimethylaminoethyl methacrylate)

Stimuli-responsive hydrogel systems have attracted great interest as smart materials for numerous potential applications. Recently, cationic pH-responsive poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA)-based microgels and hydrogels with good biocompatibility have attracted great interest due to their potential applications in the biomedical and pharmaceutical fields. These microgels and hydrogels can swell in acidic environments due to protonation of tertiary amine groups and deswell in alkaline circumstance due to deprotonation of tertiary amine groups. In this chapter, cationic pH-responsive PDMAEMA microgels with excellent pH responsiveness and significant swelling at low pH values are introduced. Additionally, particles with narrow size distribution are preferable in drug delivery systems; thereby PDMAEMA microcapsules with high monodispersity are prepared using a microfluidic technology. Next, considering the fast response rate that is needed in many applications, cationic polymeric hydrogels with rapid response are demonstrated. Then, a pH-responsive composite membrane system with PDMAEMA hydrogels as pumping elements for improved controlled release is introduced. Finally, PDMAEMA-modified CO₂-responsive cationic hydrogels are discussed. These PDMAEMA-based microgels and hydrogels are highly potential in various applications such as drug delivery systems, chemical carriers, sensors and so on.