Preparation method of composite luminescent thin film of sulfonated poly (p-phenylene) and layered double hydroxides

A process for preparing a composite luminescent film of sulfonated poly(p-phenylene) anion/layered double hydroxides (LDHs), comprising:

• 1) preparing nitrate-intercalated LDHs by a coprecipitation method or an ion-exchange method, wherein the coprecipitation method comprises:
• preparing a mixed nitrate solution containing a soluble divalent metal cation M2+ and a soluble trivalent metal cation M3+with a molar ratio M2+/M3+of 2-4 and M2+concentration of 0.1-1 mol/L;
• preparing a solution of NaOH or KOH, wherein the molar ratio of NaOH or KOH to the sum of M2+and M3+being 2-2.5;
• and
• under stirring, slowly dropwise adding the mixed nitrate solution into the NaOH of KOH solution under N2 protection, regulating the pH of the resulting solution to 7-10 with 1-5 mol/L NaOH solution, crystallizing at 60° C-70° C. for 12-24 hours, and recovering the nitrate-intercalated LDHs from the crystallization product, and wherein the ion-exchange method comprises:
• preparing a mixed nitrate solution containing a soluble divalent metal cation M2+ and a soluble trivalent metal cation M3+with a molar ratio M2+/M3+ of 2-4 and M2+ concentration of 0.1-1 mol/L;
• preparing a urea solution, wherein the molar ratio of urea to the sum of M2+ and M3+is 3-5;
• reacting the mixed nitrate solution and the urea solution at 100° C.-150° C. for 12-36 hours in a PTFE-lined pressure reactor, and recovering carbonate-intercalated LDHs from the reaction product;
• and
• carrying out an ion-exchange reaction between sodium nitrate and the carbonate-intercalated LDHs at a mass ratio of 200:1-500:1 for 12-24 hours under inert gas protection, and recovering nitrate-intercalated LDHs from the reaction product;
• 2) stirring, in formaldehyde solvent per 100 mL, 0.05-0.2 g of nitrate intercalated LDHs at 3,000-5,000 rpm for 12-36 hours to delaminate, centrifuging the delaminated LDHs solution and discarding the precipitate to obtain a clear transparent colloidal solution;
• 3) preparing 0.1-1 g/L sulfonated poly(p-phenylene) solution;
• 4) subjecting a substrate to hydrophilic treatment, soaking said treated substrate in the colloidal solution for 10-20 min, fully washing with deionized water, then placing the substrate in the sulfonated poly(p-phenylene) solution, and soaking it for 10-20 min, and fully washing with deionized water to obtain a one-cycle composite film of sulfonated poly(p-phenylene)/LDHs;
• and
• 5) repeating soaking the substrate in the colloidal solution for 10-20 min, fully washing with deionized water, then placing the substrate in the sulfonated poly(p-phenylene) solution, and soaking it for 10-20 min, and fully washing with deionized water, to obtain a multilayer composite film of sulfonated poly(p-phenylene)/LDHs.