Low-temperature resistant perfluoropolyether-based magnetic liquid and preparation method thereof

A preparation method of a perfluoropolyether-based magnetic liquid, comprising:

• S1, dispersing magnetic nanoparticles coated with graphene oxide into a solution of N,N-dimethylformamide to obtain solution A;
• S2, dispersing a surfactant into dichloromethane, and adding triethylamine as a cosolvent to obtain solution B;
• S3, mixing the solution A and the solution B uniformly, heating them under reflux and stirring them for a modification reaction;
• and after the modification reaction is completed, washing and drying a reaction product to obtain the modified magnetic nanoparticles coated with the graphene oxide;
• S4, dispersing the modified magnetic nanoparticles coated with the graphene oxide into a base carrier liquid to prepare the perfluoropolyether-based magnetic liquid;
• wherein the surfactant is a perfluoroalkylamine;
• and the base carrier liquid is a perfluoropolyether oil;
• a mass ratio of the magnetic nanoparticles coated with the graphene oxide to the surfactant is from 20:1 to 1:1;
• the modification reaction is performed at a temperature of 50 to 120° C. for a time period of 20 to 50 hours.