Zamfir Mirela, Rodriguez-Emmenegger Cesar, Bauer Stella, Barner Leonie, Rosenhahn Axel, Barner-Kowollik Christopher
Soft Matter Synthesis Laboratory, Institut für Biologische Grenzflächen (IBG), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
J Mater Chem B. 2013 Nov 28;1(44):6027-6034. doi: 10.1039/c3tb20880j. Epub 2013 Oct 4.
The reversible addition-fragmentation chain transfer polymerization of 2-hydroxyethyl methacrylate (HEMA) from surfaces (S-RAFT) using an R-group-attached chain transfer agent (CTA) is presented. The approach was exploited for the efficient preparation of well-defined PHEMA brushes of up to 50 nm thickness in a controlled fashion without using any cytotoxic catalyst. The chemical composition, morphology and wettability of the samples were assessed by X-ray photoelectron spectroscopy, atomic force microscopy and water contact angle measurements, while the growth kinetics were studied by monitoring the dry thickness via spectroscopic ellipsometry. The mechanism and kinetics of the RAFT polymerization on the surface - in the presence of a sacrificial CTA and of solvent mixtures with different polarities - were investigated. A marked effect of the concentration of the sacrificial CTA on the kinetics was observed. Importantly - and for the first time - the living PHEMA brushes were exploited as macroRAFT agents for chain extension, and thicknesses up to 70 nm were achieved. The prepared PHEMA brushes were challenged with protein solutions demonstrating their resistance to fouling.
本文介绍了使用连接有R基团的链转移剂（CTA）从表面进行甲基丙烯酸2-羟乙酯（HEMA）的可逆加成-断裂链转移聚合反应（S-RAFT）。该方法用于以可控方式高效制备厚度达50 nm的明确定义的聚甲基丙烯酸2-羟乙酯（PHEMA）刷，且无需使用任何细胞毒性催化剂。通过X射线光电子能谱、原子力显微镜和水接触角测量来评估样品的化学成分、形态和润湿性，同时通过椭圆偏振光谱法监测干膜厚度来研究生长动力学。研究了在存在牺牲性CTA和不同极性溶剂混合物的情况下表面RAFT聚合的机理和动力学。观察到牺牲性CTA的浓度对动力学有显著影响。重要的是，首次将活性PHEMA刷用作大分子RAFT试剂进行链延伸，实现了高达70 nm的厚度。用蛋白质溶液对制备的PHEMA刷进行测试，证明了它们的抗污染能力。
