Preparation method of polydopamine-based modified composite polymer diaphragm

The invention relates to a polydopamine-based modified composite polymer diaphragm which is characterized in that a preparation method specifically comprises the following steps: (a) soaking nonwoven fabric with the size of 10cm*15cm in 10mmol/L dopamine solution for 24h to obtain polydopamine-pretreated nonwoven fabric; (b) meanwhile, treating the polydopamine-pretreated nonwoven fabric with a mixed system containing water, polymer particles and a water-based binder to obtain a diaphragm, wherein the ratio of the water-based binder to the water to the polymer particles is (0.5-5g):50g:(0.1-0.5g); and (c) performing vacuum drying on the diaphragm at 70-85 DEG C to obtain a polydopamine-based modified composite polymer particle diaphragm. Aiming at the shortcomings of an existing diaphragm, after the nonwoven fabric is treated by dopamine, the diaphragm surface is in a hydrophilic state from a hydrophobic state, and the adopted water-based binder is environmentally-friendly; the added polymer particles can imp