Composition comprising for 100% of its weight: - From 99% by weight to 20% by weight of at least one compound of formula (Ia) R'-O-A-O-H (Ia), formula (Ia) wherein R' is either a monovalent radical of formula (IIa): wherein R1 is a saturated or unsaturated, linear or branched alphatic radical, comprising from 7 to 30 carbon atoms, R2 is a hydrogen atom or a radical chosen from the radicals methyl, isopropyl, isobutyl, 1-methyl propyl, hydroxymethyl, 1-hydroxy ethyl, thiomethyl, 2-methylthio ethyl, 4-aminobutyl, 3-guanidino propyl, 3-ureido propyl, (1-amino carbonyl) methyl, 2-(amino carbonyl) ethyl, benzyl, 4-hydroxy benzyl, 3,4-dihydroxy benzyl, [1H-indol-3-yl] methyl, (1H-imidazol-4-yl) methyl, 3-amino propyl and R3 is a hydrogen atom or a methyl radical; or a monovalent radical of formula (IIb): wherein R1 is such as defined in the formula (IIa) and R4 is a hydrogen atom or a hydroxy radical; and formula (Ia) wherein A is the divalent radical of formula: -CH -[C]p-CH - wherein X1, X2, X3 and X4, are identical or different, and are either a hydrogen atom or a methyl radical or an ethyl radical, and p is an integer greater than or equal to 1 and less than or equal to 6; and - From 1 % by weight to 80% by weight of at least one compound of formula (Ib): R-O-A-O-R (Ib), formula (Ib) wherein R, is either a monovalent radical of formula (IIa): wherein R1 is a saturated or unsaturated, linear or branched alphatic radical, comprising from 7 to 30 carbon atoms, R2 is a hydrogen atom or a radical chosen from the radicals methyl, isopropyl, isobutyl, 1-methyl propyl, hydroxymethyl, 1-hydroxy ethyl, thiomethyl, 2-methylthio ethyl, 4-aminobutyl, 3-guanidino propyl, 3-ureido propyl, (1-amino carbonyl) methyl, 2-(amino carbonyl) ethyl, benzyl, 4-hydroxy benzyl, 3,4-dihydroxy benzyl, [1-indol-3-yl] methyl, (1-imidazol-4-yl) methyl, 3-amino propyl, and R3 is a hydrogen atom or a methyl radical; or a monovalent radical of formula (IIb): wherein R1 is such as defined in the formula (IIa) and R4 is a hydrogen atom or a hydroxy radical, and formula (Ib) wherein A is the divalent radical of formula: -CH -[C]p-CH - wherein X1, X2, X3 and X4, identical or different, are either a hydrogen atom, or a methyl radical, or an ethyl radical and P is an integer greater than or equal to 1 and less than or equal to 6. - From 99% by weight to 20% by weight of at least one compound of formula (Ia) R'-O-A-O-H (Ia), formula (Ia) wherein R' is either a monovalent radical of formula (IIa): wherein R1 is a saturated or unsaturated, linear or branched alphatic radical, comprising from 7 to 30 carbon atoms, R2 is a hydrogen atom or a radical chosen from the radicals methyl, isopropyl, isobutyl, 1-methyl propyl, hydroxymethyl, 1-hydroxy ethyl, thiomethyl, 2-methylthio ethyl, 4-aminobutyl, 3-guanidino propyl, 3-ureido propyl, (1-amino carbonyl) methyl, 2-(amino carbonyl) ethyl, benzyl, 4-hydroxy benzyl, 3,4-dihydroxy benzyl, [1H-indol-3-yl] methyl, (1H-imidazol-4-yl) methyl, 3-amino propyl and R3 is a hydrogen atom or a methyl radical; or a monovalent radical of formula (IIb): wherein R1 is such as defined in the formula (IIa) and R4 is a hydrogen atom or a hydroxy radical; and formula (Ia) wherein A is the divalent radical of formula: -CH -[C]p-CH - wherein X1, X2, X3 and X4, are identical or different, and are either a hydrogen atom or a methyl radical or an ethyl radical, and p is an integer greater than or equal to 1 and less than or equal to 6; and - From 1 % by weight to 80% by weight of at least one compound of formula (Ib): R-O-A-O-R (Ib), formula (Ib) wherein R, is either a monovalent radical of formula (IIa): wherein R1 is a saturated or unsaturated, linear or branched alphatic radical, comprising from 7 to 30 carbon atoms, R2 is a hydrogen atom or a radical chosen from the radicals methyl, isopropyl, isobutyl, 1-methyl propyl, hydroxymethyl, 1-hydroxy ethyl, thiomethyl, 2-methylthio ethyl, 4-aminobutyl, 3-guanidino propyl, 3-ureido propyl, (1-amino carbonyl) methyl, 2-(amino carbonyl) ethyl, benzyl, 4-hydroxy benzyl, 3,4-dihydroxy benzyl, [1-indol-3-yl] methyl, (1-imidazol-4-yl) methyl, 3-amino propyl, and R3 is a hydrogen atom or a methyl radical; or a monovalent radical of formula (IIb): wherein R1 is such as defined in the formula (IIa) and R4 is a hydrogen atom or a hydroxy radical, and formula (Ib) wherein A is the divalent radical of formula: -CH -[C]p-CH - wherein X1, X2, X3 and X4, identical or different, are either a hydrogen atom, or a methyl radical, or an ethyl radical and P is an integer greater than or equal to 1 and less than or equal to 6.