Spatially Confined Tungstate Ion Polymerization in Microcapsules

A new approach for performing the WO₄²⁻ polymerization reaction exclusively inside polyelectrolyte capsules of a micron scale size is demonstrated. This approach is based upon a pH gradient across the capsule shell (2.5 inside the capsule volume and 6.5 outside the capsule) caused by encapsulated poly(styrene sulfonate) molecules. During the first stage of the reaction, different polytungstate anions were synthesized. Crystalline WO₃ nanoparticles were formed inside the capsule as the final polymerization product.

The tungstate ion polymerization confined within a micron‐sized polyelectrolyte capsule described herein.