Lipophilic polyelectrolyte gels as super-absorbent polymers for nonpolar organic solvents

Polyelectrolyte gels that are known as super-absorbent polymers swell and absorb water up to several hundred times their dried weights and have become ubiquitous and indispensable materials in many applications. Their superior swelling abilities originate from the electrostatic repulsion between the charges on the polymer chains and the osmotic imbalance between the interior and exterior of the gels. However, no super-absorbent polymers for volatile organic compounds (VOCs), and especially for nonpolar organic solvents (epsilon<10) have been reported, because common polyelectrolyte gels collapse in such solvents owing to the formation of a higher number of aggregates of ions and ion pairs. Here, we report that a novel class of polyelectrolyte gels bearing tetra-alkylammonium tetraphenylborate as a lipophilic and bulky ionic group swell in some nonpolar organic solvents up to 500 times their dry size. Dissociation of the ionic groups even in low-dielectric media (3