A compound of formula: wherein A* is a monocyclic, polycyclic or polycondensed aromatic moiety, wherein compound is selected from compounds (L-1) to (L-3) below: wherein * B is a bridging group selected - from a C 1 -C 20 divalent alkylene group comprising at least one sulfur or oxygen atom directly bound to an sp 2 carbon atom of moiety (A*), said alkylene group being optionally fluorinated and optionally containing one or more hydroxyl groups and - from a group forming with aromatic moiety (A*) a condensed ring comprising the aromatic moiety (A*) and a non-aromatic cyclic moiety having two heteroatoms, each heteroatom being directly bound to an sp 2 carbon atom of moiety (A*); * chain (R f) comprises repeating units R°, said repeating units being chosen among the group consisting of: (i) -CFXO-, wherein X is F or CF 3, (ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF 3, with the provision that at least one of X is -F, (iii) -CF 2 CF 2 CW 2 O-, wherein each of W, equal or different from each other, are F, CI, H, (iv) -CF 2 CF 2 CF 2 CF 2 O-, (v) -(CF 2) j -CFZ-O- wherein j is an integer from 0 to 3 and Z is a group of general formula -OR f 'T 3, wherein R f ' is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings: -CFXO-, -CF 2 CFXO-, -CF 2 CF 2 CF 2 O-, - CF 2 CF 2 CF 2 CF 2 O-, with each of X being independently F or CF 3 and T 3 being a C 1 -C 3 perfluoroalkyl group; * Y is a hydrocarbon group, possibly fluorinated, which comprises at least one hydroxyl group; * G is a fluorine atom; * x is an integer of at least 1; * y is an integer ranging either - from 1 to z - x, wherein z is the number of carbon atoms of moiety (A*), when bridging group is a divalent alkylene group as defined above or - from 1 to z - 2x, when bridging group forms a condensed ring as defined above, with the proviso that, when moiety (A*) is a polycyclic or polycondensed aromatic moiety, the number of bridging carbon atoms is to be detracted from z. * B is a bridging group selected - from a C 1 -C 20 divalent alkylene group comprising at least one sulfur or oxygen atom directly bound to an sp 2 carbon atom of moiety (A*), said alkylene group being optionally fluorinated and optionally containing one or more hydroxyl groups and - from a group forming with aromatic moiety (A*) a condensed ring comprising the aromatic moiety (A*) and a non-aromatic cyclic moiety having two heteroatoms, each heteroatom being directly bound to an sp 2 carbon atom of moiety (A*); - from a C 1 -C 20 divalent alkylene group comprising at least one sulfur or oxygen atom directly bound to an sp 2 carbon atom of moiety (A*), said alkylene group being optionally fluorinated and optionally containing one or more hydroxyl groups and - from a group forming with aromatic moiety (A*) a condensed ring comprising the aromatic moiety (A*) and a non-aromatic cyclic moiety having two heteroatoms, each heteroatom being directly bound to an sp 2 carbon atom of moiety (A*); * chain (R f) comprises repeating units R°, said repeating units being chosen among the group consisting of: (i) -CFXO-, wherein X is F or CF 3, (ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF 3, with the provision that at least one of X is -F, (iii) -CF 2 CF 2 CW 2 O-, wherein each of W, equal or different from each other, are F, CI, H, (iv) -CF 2 CF 2 CF 2 CF 2 O-, (v) -(CF 2) j -CFZ-O- wherein j is an integer from 0 to 3 and Z is a group of general formula -OR f 'T 3, wherein R f ' is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings: -CFXO-, -CF 2 CFXO-, -CF 2 CF 2 CF 2 O-, - CF 2 CF 2 CF 2 CF 2 O-, with each of X being independently F or CF 3 and T 3 being a C 1 -C 3 perfluoroalkyl group; (i) -CFXO-, wherein X is F or CF 3, (ii) -CFXCFXO-, wherein X, equal or different at each occurrence, is F or CF 3, with the provision that at least one of X is -F, (iii) -CF 2 CF 2 CW 2 O-, wherein each of W, equal or different from each other, are F, CI, H, (iv) -CF 2 CF 2 CF 2 CF 2 O-, (v) -(CF 2) j -CFZ-O- wherein j is an integer from 0 to 3 and Z is a group of general formula -OR f 'T 3, wherein R f ' is a fluoropolyoxyalkene chain comprising a number of repeating units from 0 to 10, said recurring units being chosen among the followings: -CFXO-, -CF 2 CFXO-, -CF 2 CF 2 CF 2 O-, - CF 2 CF 2 CF 2 CF 2 O-, with each of X being independently F or CF 3 and T 3 being a C 1 -C 3 perfluoroalkyl group; * Y is a hydrocarbon group, possibly fluorinated, which comprises at least one hydroxyl group; * G is a fluorine atom; * x is an integer of at least 1; * y is an integer ranging either - from 1 to z - x, wherein z is the number of carbon atoms of moiety (A*), when bridging group is a divalent alkylene group as defined above or - from 1 to z - 2x, when bridging group forms a condensed ring as defined above, with the proviso that, when moiety (A*) is a polycyclic or polycondensed aromatic moiety, the number of bridging carbon atoms is to be detracted from z. - from 1 to z - x, wherein z is the number of carbon atoms of moiety (A*), when bridging group is a divalent alkylene group as defined above or - from 1 to z - 2x, when bridging group forms a condensed ring as defined above, with the proviso that, when moiety (A*) is a polycyclic or polycondensed aromatic moiety, the number of bridging carbon atoms is to be detracted from z.