title: Effect of the grafting ratio of poly(N-isopropylacrylamide) on thermally responsive polymer brush surfaces.
abstract: Four kinds of poly(N-isopropylacrylamide)-grafted silicas with different grafting ratios and the same grafting density were prepared by atom transfer radical polymerization. The chemical groups in the stationary phase was verified by FTIR spectroscopy, and the content of elements was measured by elemental analysis. The grafting ratio of thermoresponsive chromatographic materials was measured by thermogravimetric analysis and was 2.36-21.10% mg/m2. The retention behaviors of the stationary phase with different grafting ratios were evaluated by separating five kinds of steroids and ten kinds of different hydrophobic properties compounds. With the increase in grafting ratio, the retention time of analytes was prolonged in high-performance liquid chromatography. The results showed that grafting ratio had a significant influence on the separation effect under the same grafting density. And the optimal grafting ratio of poly(N-isopropylacrylamide) was 5.81-13.15%.
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing, P.R. China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Shen
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing, P.R. China.
authors.forename: Lianqing
authors.initials: L
authors.lastname: Dong
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing, P.R. China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Luhe Teaching Hospital, Capital Medical University, Beijing, P.R. China.
authors.forename: Zongjian
authors.initials: Z
authors.lastname: Liu
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing, P.R. China.
authors.forename: Rongji
authors.initials: R
authors.lastname: Dai
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing, P.R. China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Meng
authors.affiliation: School of Life Science, Beijing Institute of Technology, Beijing, P.R. China.
authors.forename: Yulin
authors.initials: Y
authors.lastname: Deng
keywords: Atom transfer radical polymerization; grafting ratio; retention behavior; temperature response