A facile
synthetic route was developed to prepare a surface-grafted
brush layer of poly(vinyl ethers) (PVEs) directly by a radical mechanism,
with the “naked” Li+ acting as a catalyst.
Density functional theory calculations suggested that complexation
of naked Li+ to VEs significantly reduced the highest unoccupied
molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO)
energy gap from 5.08 to 0.68 eV, providing a better prospect for electron
transfer. The structure, morphology, and surface properties of grafted
polymer layers were characterized using attenuated total reflection
Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray
photoelectron spectroscopy, atomic force microscopy, and dynamic water
contact angle (DCA). Moreover, ellipsometry data indicated that the
thickness of the polymer brushes was in the range of 20–60
nm, which corresponds to the grafting densities of 0.65–1.15
chain/nm2, and DCA decreased from 84.4 to 45.3°. Most
importantly, no hydrolysis was observed for the modified surface after
30 days of exposure to phosphate-buffered saline solution, 0.1 mol/L
NaOH(eq) and 0.1 mol/L HCl(eq), demonstrating excellent hydrolysis
resistance with long service life. In addition, as a proof of concept,
the side hydroxyl groups of grafted PVEs provide active sites for
efficient fixation of bioactive molecules, e.g., glycosaminoglycan
and serum protein.