A polyaryl ether sulfone polymer solution [solution (SP)] comprising: - at least one sulfone polymer [polymer (PSI)] having recurring units, wherein more than 50 % moles, with respect to all the recurring units of polymer (PSI), are recurring units (R PSI ) selected from the group consisting of those of formulae (R PSI -1) and (R PSI -2) herein below : wherein : - each of E', equal to or different from each other and at each occurrence, is selected from the group consisting of those of formulae (E'-1) to (E'-3): - each R' is independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium ; and - j' is zero or an integer of 1 to 4 ; T is a bond or a divalent group optionally comprising one or more than one heteroatom ; preferably T is selected from the group consisting of a bond, -CH 2 -, -C(O)-, -C(CH 3 ) 2 -, -C(CF 3 ) 2 -, -C(=CCl 2 )-, -C(CH 3 )(CH 2 CH 2 COOH)-, and a group of formula : - at least one polar organic solvent [solvent (S)]; and - at least one mixture of polyhydroxyl aliphatic alcohols having from 1 to 6 carbon atoms or derivatives thereof [mixture (PHA)], said mixture (PHA) comprising at least one ethylene glycol compound [compound (EthyGly)] and at least one glycerol compound [compound (Gly)]. - at least one sulfone polymer [polymer (PSI)] having recurring units, wherein more than 50 % moles, with respect to all the recurring units of polymer (PSI), are recurring units (R PSI ) selected from the group consisting of those of formulae (R PSI -1) and (R PSI -2) herein below : wherein : - each of E', equal to or different from each other and at each occurrence, is selected from the group consisting of those of formulae (E'-1) to (E'-3): - each R' is independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium ; and - j' is zero or an integer of 1 to 4 ; T is a bond or a divalent group optionally comprising one or more than one heteroatom ; preferably T is selected from the group consisting of a bond, -CH 2 -, -C(O)-, -C(CH 3 ) 2 -, -C(CF 3 ) 2 -, -C(=CCl 2 )-, -C(CH 3 )(CH 2 CH 2 COOH)-, and a group of formula : - at least one polar organic solvent [solvent (S)]; and - at least one mixture of polyhydroxyl aliphatic alcohols having from 1 to 6 carbon atoms or derivatives thereof [mixture (PHA)], said mixture (PHA) comprising at least one ethylene glycol compound [compound (EthyGly)] and at least one glycerol compound [compound (Gly)]. - each of E', equal to or different from each other and at each occurrence, is selected from the group consisting of those of formulae (E'-1) to (E'-3): - each R' is independently selected from the group consisting of halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine and quaternary ammonium ; and - j' is zero or an integer of 1 to 4 ; T is a bond or a divalent group optionally comprising one or more than one heteroatom ; preferably T is selected from the group consisting of a bond, -CH 2 -, -C(O)-, -C(CH 3 ) 2 -, -C(CF 3 ) 2 -, -C(=CCl 2 )-, -C(CH 3 )(CH 2 CH 2 COOH)-, and a group of formula : - at least one polar organic solvent [solvent (S)]; and - at least one mixture of polyhydroxyl aliphatic alcohols having from 1 to 6 carbon atoms or derivatives thereof [mixture (PHA)], said mixture (PHA) comprising at least one ethylene glycol compound [compound (EthyGly)] and at least one glycerol compound [compound (Gly)]. <EOS>