TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The co-solvent has a Hansen polarity parameter of 5-12 (expressed in square root of MPa). The co-solvent is methyl ethyl ketone, 1-propanol or tetrahydrofuran, preferably 1-propanol. The co-solvent has a boiling point of at most 99 degrees C.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: In the step (a) a homogenizer, preferably a high shear homogenizer is used. Preferred Components: The midblock sulfonated block copolymers are either linear or branched and preferably are of formulae (A-B1-A), ((A-B1)n(A)), ((A-B1-A)n), ((A-B1-A)nX), ((A-B1)nX), (A-B1-D-B-A), (A-D-B1-D-A), ((A-D-B1)n(A)), ((A-B1-D)n(A)), ((A-B1-D)nX) and/or ((A-D-B1)nX), preferably linear structures of formulae (A-B1-A), ((A-B)2X), ((A-B-D)2X) and ((A-D-B)2X) or radial structures of formulae ((A-B)nX) and ((A-D-B)nX). The midblock sulfonated block copolymers have ion exchange capacity of 0.2-2, preferably 0.5-1.25. The mass ratio of the hydrocarbon solvent to the co-solvent is 10:1-1:2, preferably 3:1 to 1:1. The cement has solids content of 5-60 (preferably 10-30) mass%.n = 2-30, preferably 3-6;X = coupling agent residue;A = non-sulfonated styrenic polymer end-block, preferably a polymer block having an apparent number average molar mass of 1000-60000, preferably 7000-20000;B1 = interior styrenic polymer block carrying sulfonyl groups and/or its derivatives, preferably a polymer block having an apparent number average molar mass 10000-300000, preferably 19000-100000; andD = interior polymer block that has a glass transition temperature of less than 20 degrees C, preferably a polymer block having an apparent number average molar mass 1000-60000, preferably 5000-20000, where the molar mass refers to polystyrene equivalent or apparent, molar mass of the polymer or block of the copolymer, measured with gel permeation chromatography using polystyrene calibration standards, according to ASTM D5296-11. EXAMPLE - 20 g MD9100 (RTM: Sulfonated styrenic block copolymer pentablock copolymer) solution was mixed with 7.5 g co-solvent (27% of methyl ethyl ketone, 27% tetrahydrofuran and 27% 1-propanol) and 30 g water in Ultra-turrax T25 (RTM: High-performance dispersing instrument) at 13500 rpm. Then the solvent and the majority of the co-solvent were stripped off under reduced pressure at elevated temperature to obtain a stable emulsion of midblock sulfonated styrenic block copolymer.