{
    "protocol": "A series of copolymers consisting of hydrophilic hydroxyethyl methacrylate (HEA), hydrophobic methyl methacrylate (MMA), and benzophenone-based acrylate (BP-Acrylate) units were synthesized by thermally triggered radical polymerization. The hydrophilic-hydrophobic balance of the copolymers can be adjusted by varying the molar ratio of HEA to MMA. After synthesis, the copolymers were coated on the surface of PC plates, followed by exposure to UV light to achieve covalently bonded anti-fogging coatings.A series of acrylate copolymers were synthesized via free radical copolymerization containing HEA (3.0g), MMA (7.0g), and 4-BP acrylate (0.5g) with AIBN (0.21g, ~2% of total mass weight of monomers). The monomers were dissolved in 10 mL DMF to form a homogeneous solution. The mixture was maintained at 60°C for 12 hours and then dialyzed against distilled water using 5 kDa MWCO dialysis tubing with a regenerated cellulose membrane for 24 hours with 3 water changes to remove the organic solvent and unreacted monomer. The sample was labeled as P-30% according to the mass percentage of HEA (30 wt.%) to the total mass weight of HEA and MMA. Other products with different mass percentages of HEA (50, 70, and 90 wt.%) were prepared and labeled as P-50%, P-70%, and P-90% accordingly. The purified copolymers (P-30%, P-50%, P-70%, P-90%) were dissolved in D6-DMSO to form a uniform solution. 1H-NMR measurements were conducted on a 400 MHz NMR spectrometer, with ~100 mg of polymer dissolved in 1 mL D6-DMSO solvent. The chemical structures were characterized by the 1H NMR spectra, and the monomer unit ratios were calculated from the peak integration values of the spectra. Number-average molecular weights (Mn) and molecular weight distributions (PDI = Mw/Mn) were determined by gel permeation chromatography (GPC) using linear Tskgel Super columns (AW3000 and AW5000), with OPTILAB DSP Interferometric Refractometer as the detector. The eluent was DMF at a flow rate of 1.0 mL min-1. Monodispersed polystyrene standards were used to generate the calibration curve, yielding Mn of the copolymers in the range of 63.4 to 79.1 kDa and PDI ranging from 1.3 to 1.6.Cut PC plates into rectangular pieces (2.5x7.5 cm), sonicate in ethanol and water, and dry completely in a vacuum oven. Dissolve resultant copolymers in acetone to create 10 wt.% solutions. Immerse PC plates into the copolymer solution for 60 s, then suspend in air for 20 s. Illuminate the copolymer coated PC plates with a UV lamp for 3 minutes (300 W, 360 nm) to obtain UV curable coatings. Wash prepared coatings with acetone and dry in a vacuum oven at 80 °C, naming them C-30%, C-50%, C-70%, C-90% respectively.The copolymers were synthesized through a thermally triggered free-radical polymerization reaction using hydrophilic HEA, hydrophobic MMA, and 4-BP-acrylate units. The 4-BP-acrylate groups function as a UV photo-initiator to immobilize the copolymer on the PC substrate surface. Under UV irradiation, the BP-based groups are excited to a singlet state, then jump to a triplet state, undergoing a hydrogen-abstracting reaction from the substrates, followed by a coupling reaction that covalently bonds the copolymers to the substrate surface. The mass percentages of HEA and MMA can be adjusted to control the surface zwitter-wettable behaviors. The desired molar ratios of HEA/MMA/4-BP acrylate in copolymers are monitored and confirmed through 1H NMR analysis. Post-UV treatment, the coatings are cleaned to remove unbonded copolymers and are evaluated by ATR-FTIR spectroscopy for characterization."
}