Crosslinked colloids with cyclopropenium cations

ABSTRACT Chemical crosslinkers are commonly used to stabilize both natural and synthetic macromolecules, while providing opportunities to install functionality and modulate polymer architecture. Here, we introduce the aromatic cyclopropenium cation as a tri‐functional crosslinker of secondary amine‐containing polymers. The one‐step crosslinking reaction is rapid and requires no subsequent purification. When dispersed in aqueous media, the crosslinked polymers form spherical nanoparticles with highly positive charge that is maintained even in alkaline conditions. This synthetic strategy will enable the incorporation of cyclopropenium into a wide variety of macromolecules. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2641–2645 The aromatic cyclopropenium cation is used as a crosslinker for secondary‐amine containing polymers. In a one‐step crosslinking reaction under ambient conditions without purification, spherical nanoparticles are prepared with high thermal stability and permanent positive charge across a wide pH range.