Neutron Reflectivity Study on the Postpolymerization Modification of Poly(2-hydroxyethyl methacrylate) Brushes

详细信息    查看全文

• 作者：Nicolas Schu虉wer ; Thomas Geue ; Juan Pablo Hinestrosa ; Harm-Anton Klok
• 刊名：Macromolecules
• 出版年：2011
• 出版时间：September 13, 2011
• 年：2011
• 卷：44
• 期：17
• 页码：6868-6874
• 全文大小：924K
• 年卷期：v.44,no.17(September 13, 2011)
• ISSN：1520-5835

文摘

Postpolymerization modification reactions are widely employed to prepare functional polymer brushes. Relatively little is known, however, about the distribution of functional groups in such postmodified brushes. Using neutron reflectometry and UV鈥搗is spectroscopy as principal tools, this article investigates the p-nitrophenyl chloroformate (NPC)-mediated postpolymerization modification of poly(2-hydroxyethyl methacrylate) (PHEMA) brushes, prepared via surface-initiated atom transfer radical polymerization, with D-10 leucine and D-3 serine. The neutron reflectometry experiments indicate that the postpolymerization modification depends both on brush thickness and grafting density. Whereas for dense brushes, postpolymerization modification with D-10 leucine is limited to the top 200 脜 of the brush, independently of the brush thickness, the extent of postmodification can be significantly enhanced by decreasing the grafting density of the brush or by using the more hydrophilic and sterically less demanding D-3 serine, which reflects the ability of this amino acid to more readily penetrate the brush. UV鈥搗is experiments revealed that the NPC activation is also nonuniform, but brush thickness and grafting density dependent, which adds to brush thickness and density and the nature of the amino acid as another of a complex set of variables that determine the final distribution of functional groups in postmodified brushes.