Preparation of perfusive chromatographic materials via shear-induced reactive gelation

A simple method for producing highly porous materials suitable for chromatographic applications is discussed. Starting from a dispersion of polymer core-shell nanoparticles (latex), micrometer sized clusters (100 μm) are produced via shear-induced Reactive Gelation. Thanks to their fractal structure, these aggregates exhibit highly porous structures, with pore size distribution ranging from 0.1 to several micrometers. The effect of different properties of the primary nanoparticles on the qualities of the final products is also investigated. Particle architecture, namely the ratio between the hard, highly crosslinked core, and the soft, poorly crosslinked shell, turned out to be the most important parameter to be tuned in order to obtain highly porous and mechanically resistant clusters. The final materials can be easily slurry-packed into conventional chromatographic columns. In comparison to other commercial stationary phases, these materials show not only much lower pressure drops at very high flow rates (i.e. <0.2 bar/cm at 6 mL/min), but also HETP profiles independent of fluid velocity when measured with tracers of sizes comparable to typical bio-macromolecules. Moreover, these materials, while offering the key advantage of being in a slurry form and thus easily packable and scalable, have a behavior that closely resembles that of monoliths, in which convective flow contribution dominates.