title: Ultrathin, biomimetic, superhydrophilic layers of cross-linked poly(phosphobetaine) on polyethylene by photografting.
abstract: Ultrathin, biomimetic, superhydrophilic hydrogel layers, composed of cross-linked poly(2-methacryloyloxyethyl phosphorylcholine), are formed on low-density polyethylene films via ultraviolet-initiated surface graft polymerization. The layers are 19-58 nm thick as revealed by electron microscopy and have three-dimensional networks; the unique network structure, along with its zwitterionic nature, rather than surface roughness results in superhydrophilicity, that is, the water contact angle around 5°. This superhydrophilicity depends on a variety of factors, including the concentration of the monomer and cross-linker, the type of reaction solvents, the reaction and drying time, the intensity of UV light, and the way of measurement of water contact angles. Superhydrophilicity is obtained under a fixed ratio (e.g., 1/1) of the monomer to cross-linker, a reaction time over 120 s, a short drying time, (75%) ethanol as the reaction solvent, and low-intensity UV light, largely because these factors together generate optimal three-dimensional networks of cross-links.
authors.affiliation: School of Materials Science and Mechanical Engineering, Beijing Technology and Business University , Beijing 100048, P. R. China.
authors.forename: Biao
authors.initials: B
authors.lastname: Yang
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Duan
authors.forename: Jijun
authors.initials: J
authors.lastname: Huang
mesh_terms: D001622:Betaine / Q000737:chemistry*; D040761:Biomimetic Materials / Q000138:chemical synthesis*; D020100:Hydrogels / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D010766:Phosphorylation; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000737:chemistry; D010781:Photography / Q000295:instrumentation; D020959:Polyethylene / Q000737:chemistry*; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry*; D013499:Surface Properties; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D020100:Hydrogels; D011109:Polymethacrylic Acids; C115766:poly(2-methacryloyloxyethyl-phosphorylcholine); D014867:Water; D010767:Phosphorylcholine; D001622:Betaine; D020959:Polyethylene