NOVELTY - Double-quaternary ammonium cation and anion molecular exchange film comprises quaternized amino groups of chitosan molecules and diquaternary cation/crosslinked acrylamide block polymers, which are formed by a molecular quaternary cation polymerization, where the film has an interpenetrating network structure.    USE - The double-quaternary ammonium cation and anion molecular exchange film is useful in a fuel battery.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for producing double quaternary ammonium cation and anion molecular exchange film, comprising (a) adding 20% of isopropanol solution to the quaternized chitosan under mechanical stirring in a water bath heated to 80-90 degrees C, then adding an equal volume of 2,3-epoxypropyltrimethylammonium chloride to the reaction mixture, stirring the reaction mixture under thermostatic condition and reduced pressure for 8-12 hours after distillation to obtain quaternized chitosan, drying the quaternized chitosan at 70-90 degrees C for 30-50 minutes, and crushing the quaternized chitosan having a degree of deacetylation of greater than 95%, or 65%; and (b) reacting a substituted 3-amino-5-ethyl-6-hydroxymethyl-2-methoxymethyl-tetrahydro-pyran-4-ol with trimethyl(oxiran-2-ylmethyl)ammonium chloride to give 3-ethyl-2-(hydroxymethyl)-6-(methoxymethyl)-5-((2-methyl-3-(trimethyl-5-azanyl)propyl)amino)tetrahydropyran-4-ol, adding acrylamide and initiator potassium persulfate aqueous solution to the reaction mixture, maintaining the temperature of the reaction mixture to be 70-80 degrees C, then adding a portion of double-quaternary ammonium cation molecule monomer, standing for 25-35 minutes, mechanically stirring for 8-12 minutes, further adding glutaric dialdehyde and a solvent to the reaction mixture, mechanically stirring for 25-35 minutes after ultrasonic treatment, and evaporating the solvent to obtain the film containing a potassium hydroxide solution having a concentration of 0.5-1.5 M to prepare quaternary ammonium chitosan acetic acid solution, where the diquaternary cation molecules of maleic monomers are alkylene group of diethyl bis(octyl dimethyl ammonium bromide or chloride).