Functional Fluoropolymer Surfactants for Droplet Generation in Microfluidics

Fluorinated surfactants play an important role in droplet-based microfluidics, enabling the rapid generation of uniform droplets, which is crucial for diverse applications. However, commercial fluorosurfactants are expensive and feature complex chemical structures that limit their ability to confer desired functionalities onto droplets. In this study, we employ a versatile and facile strategy using reversible addition–fragmentation chain transfer (RAFT) polymerization to produce well-defined droplets with facial tunability in functionalities. Various types of fluorinated surfactants have been prepared and investigated, encompassing hydrophilic poly(2-hydroxyethyl acrylate), thermal-responsive poly(N-isopropylacrylamide), pH-responsive poly(2-(dimethylamino)ethyl acrylate), and zwitterionic polymers. Moreover, our study demonstrates the utility of these surfactants in producing ion-exchange beads through in situ photopolymerization with precisely controlled sizes. This work unveils a promising strategy for designing and synthesizing functional fluorinated surfactants, thereby facilitating the development of ion-exchange resins for potential high-value applications.