Hill Jacob A, Endres Kevin J, Meyerhofer John, He Qiming, Wesdemiotis Chrys, Foster Mark D
Department of Polymer Science, The University of Akron, Akron, Ohio 44325, United States.
Department of Chemistry, Saint Vincent College, Latrobe, Pennsylvania 15650, United States.
ACS Macro Lett. 2018 Jul 17;7(7):795-800. doi: 10.1021/acsmacrolett.8b00394. Epub 2018 Jun 21.
The surface of a blend of 6 kDa polystyrene and 6 kDa polystyrene functionalized with hydroxymethyl ends not only is depleted of the higher energy end groups but also is depleted of any segments belonging to the functionalized chains. This is demonstrated using the emerging technique of surface layer matrix-assisted laser desorption ionization time-of-flight mass spectrometry (SL-MALDI-ToF-MS), which detects entire chains that have any repeat unit at the outer surface, and requires no labeling. Detecting entire chains provides information about the relationship of chain functionalization to surface segregation behavior of entire chains. That the surface is depleted of interior segments of functionalized chains as well as of the ends is remarkable, since the functionality at the single chain end involves less than 0.5 wt % of the functionalized polymer chain.
6 kDa聚苯乙烯与经羟甲基封端的6 kDa聚苯乙烯的共混物表面，不仅缺少高能端基，而且缺少属于功能化链的任何链段。这是通过新兴的表面层基质辅助激光解吸电离飞行时间质谱（SL-MALDI-ToF-MS）技术得以证明的，该技术可检测在外表面具有任何重复单元的完整链，且无需标记。检测完整链可提供有关链功能化与完整链表面偏析行为之间关系的信息。功能化链的内部链段以及链端在表面均缺失，这一点很显著，因为单链端的官能团在功能化聚合物链中所占比例不到0.5 wt%。
