Dübner Matthias, Gevrek Tugce N, Sanyal Amitav, Spencer Nicholas D, Padeste Celestino
†Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
‡Laboratory for Surface Science and Technology, Department of Materials, ETH Zürich, CH-8093 Zürich, Switzerland.
ACS Appl Mater Interfaces. 2015 Jun 3;7(21):11337-45. doi: 10.1021/acsami.5b01804. Epub 2015 May 22.
We demonstrate a new approach to grafting thiol-reactive nanopatterned copolymer-brush structures on polymeric substrates by means of extreme ultraviolet (EUV) interference lithography. The copolymer brushes were designed to contain maleimide functional groups as thiol-reactive centers. Fluoropolymer films were exposed to EUV radiation at the X-ray interference lithography beamline (XIL-II) at the Swiss Light Source, in order to create radical patterns on their surfaces. The radicals served as initiators for the copolymerization of thiol-ene "clickable" brushes, composed of a furan-protected maleimide monomer (FuMaMA) and different methacrylates, namely, methyl methacrylate (MMA), ethylene glycol methyl ether methacrylate (EGMA), or poly(ethylene glycol) methyl ether methacrylate (PEGMA). Copolymerization with ethylene-glycol-containing monomers provides antibiofouling properties to these surfaces. The number of reactive centers on the grafted brush structures can be tailored by varying the monomer ratios in the feed. Grafted copolymers were characterized by using attenuated total reflection infrared (ATR-IR) spectroscopy. The reactive maleimide methacrylate (MaMA) units were utilized to conjugate thiol-containing moieties using the nucleophilic Michael-addition reaction, which proceeds at room temperature without the need for any metal-based catalyst. Using this approach, a variety of functionalities was introduced to yield polyelectrolytes, as well as fluorescent and light-responsive polymer-brush structures. Functionalization of the brush structures was demonstrated via ATR-IR and UV-vis spectroscopy and fluorescence microscopy, and was also indicated by a color switch. Furthermore, grafted surfaces were generated via plasma activation, showing a strongly increased wettability for polyelectrolytes and a reversible switch in static water contact angle (CA) of up to 18° for P(EGMA-co-MaMA-SP) brushes, upon exposure to alternating visible and UV-light irradiation.
我们展示了一种通过极紫外（EUV）干涉光刻技术在聚合物基底上接枝硫醇反应性纳米图案化共聚物刷结构的新方法。共聚物刷被设计为含有马来酰亚胺官能团作为硫醇反应中心。含氟聚合物薄膜在瑞士光源的X射线干涉光刻光束线（XIL-II）处暴露于EUV辐射，以便在其表面产生自由基图案。这些自由基用作由呋喃保护的马来酰亚胺单体（FuMaMA）和不同的甲基丙烯酸酯，即甲基丙烯酸甲酯（MMA）、乙二醇甲基醚甲基丙烯酸酯（EGMA）或聚（乙二醇）甲基醚甲基丙烯酸酯（PEGMA）组成的硫醇-烯“可点击”刷共聚合的引发剂。与含乙二醇的单体共聚合为这些表面提供了抗生物污损性能。接枝刷结构上的反应中心数量可以通过改变进料中的单体比例来调整。通过衰减全反射红外（ATR-IR）光谱对接枝共聚物进行了表征。反应性甲基丙烯酸马来酰亚胺（MaMA）单元用于通过亲核迈克尔加成反应共轭含硫醇部分，该反应在室温下进行，无需任何金属基催化剂。使用这种方法，引入了多种功能以产生聚电解质以及荧光和光响应性聚合物刷结构。通过ATR-IR、紫外可见光谱和荧光显微镜证明了刷结构的功能化，并且还通过颜色变化表明了这一点。此外，通过等离子体活化产生了接枝表面，对于聚电解质显示出润湿性大大增加，并且对于P（EGMA-co-MaMA-SP）刷，在交替暴露于可见光和紫外光照射时，静态水接触角（CA）可逆变化高达18°。
