Charge-selective separation and recovery of organic ionic dyes by polymeric micelles (PMs) are reported. Branched polyethylenimine (PEI) functionalized with 4-cetyloxybenzaldehyde (CBA) via Schiff-base bonds (PEI@CBA) can extract an anionic dye from cationic contaminants, and transfer it from an aqueous phase into an apolar oil phase, and thus leading to separation. While a physical micelle of PAA@PS, with polyacrylic acid (PAA) as core and polystyrene (PS) as shell, can selectively extract a cationic dye from anionic contaminants. When polar, yet nonionic groups are eliminated from the core of a PM, charge selectivity can be significantly enhanced. Although many anionic-cationic dyes can form a poorly water-soluble complex or precipitate, separation is still feasible with a reasonably designed PM. Finally, entrapment of a guest by a PM is found easy but release may be difficult; in this case, PEI@CBA with an acid-sheddable shell, can recover the entrapped guest. It is also found the encapsulation of a dye is usually accompanied with dye stacking, resulting in a changed UV/vis spectrum. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 872-881