Monodisperse polymeric ionic liquid microgel beads with multiple chemically switchable functionalities.

We present simple, inexpensive microfluidics-based fabrication of highly monodisperse poly(ionic liquid) microgel beads with a multitude of functionalities that can be chemically switched in facile fashion by anion exchange and further enhanced by molecular inclusion. Specifically, we show how the exquisite control over bead size and shape enables extremely precise, quantitative measurements of anion- and solvent-induced volume transitions in these materials, a crucial feature driving several important applications. Next, by exchanging diverse anions into the synthesized microgel beads, we demonstrate stimuli responsiveness and a multitude of novel functionalities including redox response, controlled release of chemical payloads, magnetization, toxic metal removal from water, and robust, reversible pH sensing. These chemically switchable stimulus-responsive beads are envisioned to open up a vast array of potential applications in portable and preparative chemical analysis, separations and spatially addressed sensing.