Synthesis of an Anionically Chargeable, High-Molar-Mass, Second-Generation Dendronized Polymer and the Observation of Branching by Scanning Force Microscopy
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- 作者：Edis Kasë ; mi ; Wei Zhuang ; Jü ; rgen P. Rabe ; Karl Fischer ; Manfred Schmidt ; Martin Colussi ; Helmut Keul ; Ding Yi ; Helmut Cö ; lfen ; and A. Dieter Schlü ; ter
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：April 19, 2006
- 年：2006
- 卷：128
- 期：15
- 页码：5091 - 5099
- 全文大小：341K
- 年卷期：v.128,no.15(April 19, 2006)
- ISSN：1520-5126
文摘
An efficient synthesis of a methacrylate-based, second-generation (G2) dendronized macromonomer and its free radical polymerization to the corresponding high-molar-mass G2 dendronizedpolymer are described. The molar mass is determined by gel permeation chromatography (GPC), light-scattering, and analytical ultracentrifugation and compared with values estimated from a scanning forcemicroscopy (SFM) contour lengths analysis of individualized polymer strands on mica. The polymer carriesterminal tert-butyl-protected carboxyl groups, the degree of deprotection of which with trifluoroacetic acidis quantified by NMR spectroscopy using the highest molar mass sample. SFM imaging of both protected(noncharged) and unprotected (charged) dendronized polymers on solid substrates reveals mostly linearchains but also some with main-chain branches. The nature of these branches is investigated and thedegree roughly estimated to which they are formed. Finally, a synthetic model experiment is describedwhich sheds some light on the aspect of whether chain transfer, a process that could lead to covalentbranching, is of importance in the synthesis of the present dendronized polymers.