Makromolekulare Chemie II, Universität Bayreuth, D-95440 Bayreuth, Germany.
ACS Nano. 2013 Mar 26;7(3):2284-91. doi: 10.1021/nn3054347. Epub 2013 Feb 22.
A tapping-mode AFM investigation of core-shell cylindrical polymer brushes (CPBs) on mica shows that they can be ruptured upon spin-coating. Three different CPBs were synthesized, having a methacrylate backbone, carrying branches of poly[oligo(ethylene glycol)methacrylate] (POEGMA), POEGMA-block-poly[2-(dimethylamino)ethyl methacrylate] (POEGMA-b-PDMAEMA), and POEGMA-block-poly[2-(methacryloyloxy)ethyl trimethylammoniumiodide] (POEGMA-b-PMETAI). The polymer backbone of core-shell CPB with POEGMA-b-PDMAEMA or POEGMA-b-PMETAI branches is ruptured upon drying on a mica surface, while they are stable in aqueous solution. We propose that the scission behavior is induced by Coulomb interactions between PDMAEMA or PMETAI corona and the solid surface and that this interaction is stronger than one or more carbon-carbon single bonds. We control this scission behavior by tuning the surface interactions through switching the surface nature, varying pH, or adding multivalent counterions. Our study demonstrates that core-shell CPB serves as a template to directly compare the weak intermolecular forces with the strong carbon-carbon covalent bonds.
云母上的核壳圆柱形聚合物刷（CPB）的敲击模式原子力显微镜（AFM）研究表明，它们在旋涂时会发生破裂。合成了三种不同的 CPB，它们具有甲基丙烯酸酯主链，带有聚[聚（乙二醇）甲基丙烯酸酯]（POEGMA）支链、POEGMA-嵌段-聚[2-（二甲基氨基）乙基甲基丙烯酸酯]（POEGMA-b-PDMAEMA）和 POEGMA-嵌段-聚[2-（甲基丙烯酰氧基）乙基三甲基碘化铵]（POEGMA-b-PMETAI）支链。带有 POEGMA-b-PDMAEMA 或 POEGMA-b-PMETAI 支链的核壳 CPB 的聚合物主链在云母表面干燥时会发生断裂，而在水溶液中则稳定。我们提出，这种断裂行为是由 PDMAEMA 或 PMETAI 冠层与固体表面之间的库仑相互作用引起的，这种相互作用比一个或多个碳-碳单键更强。我们通过改变表面性质、改变 pH 值或添加多价抗衡离子来控制这种断裂行为，从而调节表面相互作用。我们的研究表明，核壳 CPB 可作为模板，直接比较弱的分子间力与强的碳-碳共价键。
