Microporous polymeric microsphere via surfactant-free Suzuki coupling polymerization in a single-phase: Porosity and gas uptake

Using two spirocyclic core building units, microporous polymeric spheres SPOP-5 and SPOP-6 have been successfully prepared through a surfactant-free Suzuki coupling polymerization in a single-phase, which is different from the commonly employed heterogeneous polymerization technique. Especially, for SPOP-6, the SEM image shows that the polymer consists of relatively uniform monodisperse solid microspheres with particle sizes about 500 nm in diameter. The mechanism of microsphere formation is believed to occur by a two-step process involving particle nucleation and subsequent growth. The Brunauer–Emmett–Teller (BET) specific surface area for these polymers ranges from 705 to 744 m2 g−1. Based on the gas (H2 or CO2) physisorption isotherms, an increase in the gas loading capacity with increasing specific surface area is observed. Especially, hydrogen adsorption isotherms show that the adsorption capacity of SPOP-6 for hydrogen is 1.62 wt% at 1.0 bar and 77 K, which can be competitive with, even higher than lots of porous polymers with higher BET specific surface area under the same conditions.