This application provides a
polymer brush, its preparation method, and its application in fluid drag reduction. The preparation method includes: preparation of an initiator layer; preparation of a PNIPAM
brush: under a
nitrogen atmosphere, N-isopropylacrylamide, pentamethyldiethylenetriamine, and
acrylic acid are added to a mixed
solvent of
methanol and deionized water, and then cuprous
bromide is added to obtain a
polymerization reaction solution. A substrate material coated with an initiator layer is immersed in the
polymerization reaction solution to perform a SI-ATRP reaction, and a PNIPAM
brush is obtained on the surface of the substrate material. Preparation of a DM-PNIPAM brush: 4-dimethylaminobutamine and an activator are dissolved in N,N-
dimethylformamide to obtain a modified
solvent. The substrate material grafted with the PNIPAM brush is immersed in the modified
solvent and reacted to obtain the
polymer brush, i.e., the DM-PNIPAM brush. The
polymer brush provided by this application improves its stability and durability as a drag-
reducing agent in fluid drag reduction.