NOVELTY - Preparation of aqueous emulsion of midblock sulfonated styrenic block copolymer involves providing cement of the copolymer in nonpolar solvent, mixing with co-solvent, emulsifying optionally in the presence of emulsifier, and removing the non-polar solvent, and optionally the co-solvent from the produced emulsion. The non-polar solvent has a Hansen polarity parameter ( delta p) less than 2.0 MPa1/2. The co-solvent has Hansen polarity parameter ( delta p) of 2.8-15 MPa1/2, and a Hansen hydrogen bonding parameter ( delta h) of 4.0-27 MPa1/2.    USE - Preparation of aqueous emulsion of midblock sulfonated styrenic block copolymer (claimed). Uses include but are not limited to preparation of moisture permeable membranes and coatings, fuel cells, separation equipment, clothing, energy recovery ventilation, and water purification.    ADVANTAGE - The method enables manufacture of aqueous emulsion of midblock sulfonated styrenic block copolymer having low film-forming temperature, and relatively small particle diameters due to the use of specific solvents during emulsification.    DETAILED DESCRIPTION - Preparation of aqueous emulsion of midblock sulfonated styrenic block copolymer involves providing cement of the block copolymer in non-polar solvent which is 5-12C hydrocarbon with boiling point of less than 100 degrees C, mixing cement with a co-solvent to form a mixture, emulsifying the mixture in presence of an emulsifier with water to produce an emulsion, and removing the hydrocarbon solvent, and co-solvent from the emulsion. The non-polar solvent has a Hansen polarity parameter ( delta p) less than 2.0 MPa1/2. The co-solvent is a polar aprotic or protic solvent with a Hansen polarity parameter ( delta p) of 2.8-15 MPa1/2, and a Hansen hydrogen bonding parameter ( delta h) of 4.0-27 MPa1/2.An INDEPENDENT CLAIM is included for aqueous emulsion of a midblock sulfonated styrenic block copolymer comprising at least two non-sulfonated polymer end-blocks A and at least one sulfonated block B with 10-30 %mass, preferably 10-15 %mass solid content, calculated based on emulsion. The copolymer contains 1500 ppm particles with average particle size of at most 2.0 mu m, calculated based on mass of emulsion.