PDMS-coated hypercrosslinked porous organic polymers modified via double postsynthetic acidifications for ammonia capture

Abstract

A hypercrosslinked porous organic polymer was modified by post-oxidation and post-sulfonation to obtain a porous platform with a high density of acidic groups. Such an acidified material exhibits record high NH₃ adsorption capacity per surface area, fast adsorption rate, and recyclability at low desorption temperature. Noticeably, the coating of the polymer with PDMS represents a facile and efficient route to enable both a significant improvement of low-pressure NH₃ adsorption capacity (∼40-fold enhancement; from 0.04 to 1.41 mmol g⁻¹) with respect to the non-modified polymer at 500 ppm and hydrophobicity associated with the selective sorption of NH₃ over water vapor (hydrophilic for the non-coated material). This material is easy to prepare, cost-effective, and scalable to mass production.