An investigation into the preparation of poly(1‐methylpyrol‐2‐ylsquaraine) particles

Abstract

Poly(1‐methylpyrol‐2‐ylsquaraine) particles can be prepared in a one‐pot reaction by refluxing equimolar amounts of squaric acid (3,4‐dihydroxycyclobut‐3‐ene‐1,2‐dione) and 1‐methylpyrrole in butan‐1‐ol and precipitate from the reaction as porous micrometer‐sized spheres that have potential use as molecular adsorbents in chromatography and sensors, as well as ion batteries. Previous papers that have examined the electrical, photophysical, and adsorption properties of these particles have reported their size and shape, with appropriate proof in the form of electron microscope images but have paid little attention as to the actual limits of the particle size and spherical formation. Thus, a range of experiments have been undertaken to examine the robustness, in terms of reaction variation, of the construction of these spheres. Reaction characteristics such as solvent, sequence in which reactants are added, reaction time, reactant concentration, and mode of reaction agitation have all been examined to determine the optimal conditions for the production of these spheres. Fortuitously, butan‐1‐ol remains the most suitable solvent, but reactant concentration is important to produce uniformly sized spherical particles with minimal interparticle growth.