{
    "protocol": "Synthesis of hydrophilic polymers with functional groups was achieved through a UV-assisted cross-linking method, incorporating quaternary ammonium groups into the polymer network. The process involved creating a dual-cross-linked structure using pMDHAB−AA−aziridine and PEGDA networks.Synthesis of the Prepolymer pDMAEMA−AA Copolymer: A total of 40 g of DMAEMA and 4 g of AA were added to a 250 mL flask, followed by the addition of 44 g of o-xylene and 0.44 g of AIBN (1 wt % with respect to the total monomer mass) as the thermal initiator. The polymerization was conducted at 80 °C in an oil bath with magnetic stirring for 12 h. After the reaction, the final copolymer was precipitated by hexane, and the pure pDMAEMA−AA copolymer was obtained by washing three times with hexane and drying in a vacuum oven for 24 h at 60 °C. Preparation of Quaternary Ammonium Salt: 4 g of pDMAEMA−AA copolymer and 6.24 g of 1-bromoheptane were introduced to 30 mL of acetonitrile, followed by stirring at 80 °C for 12 h. Solid residues were collected through vacuum rotary evaporation after cooling to room temperature. The products were purified and washed with hexane three times, then dried in a vacuum oven at 60 °C for 24 h to obtain the pure quaternary ammonium copolymer (pMDHAB−AA). Preparation of the Dual-Cross-Linked pMDHAB−AA/PEGDA Coating: 1.2 g of quaternary ammonium copolymer was dissolved in 8 g of deionized water with stirring for 12 h. Added 0.236 g of APA and stirred for 2 h, then added 0.024 g of PEGDA and 0.0024 g of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, stirring for 1 h. The solution was drop-coated on a clean PET film treated with oxygen plasma, followed by UV curing at 365 nm for 30 min. Single PEGDA coatings were prepared using the same UV-curing method without pMDHAB−AA and APA, while the single APA coating was cured at room temperature for 24 h."
}