Dirksen Maxim, Brändel Timo, Großkopf Sören, Knust Sebastian, Bookhold Johannes, Anselmetti Dario, Hellweg Thomas
Department of Chemistry, Physical and Biophysical Chemistry, University Bielefeld Universitätsstraße 25 D-33615 Bielefeld Germany
Department of Physics, Experimental Biophysics, University Bielefeld Universitätsstraße 25 D-33615 Bielefeld Germany.
RSC Adv. 2021 Jun 22;11(36):22014-22024. doi: 10.1039/d1ra03528b. eCollection 2021 Jun 21.
In this study we use poly(-isopropylacrylamide) (PNIPAM) based copolymer microgels to create free-standing, transferable, thermoresponsive membranes. The microgels are synthesized by copolymerization of NIPAM with 2-hydroxy-4-(methacryloyloxy)-benzophenone (HMABP) and spin-coated on Si wafers. After subsequent cross-linking by UV-irradiation, the formed layers easily detach from the supporting material. We obtain free standing microgel membranes with lateral extensions of several millimetres and an average layer thickness of a few hundred nanometres. They can be transferred to other substrates. As one example for potential applications we investigate the temperature dependent ion transport through the membranes resistance measurements revealing a sharp reversible increase in resistance when the lower critical solution temperature of the copolymer microgels is reached. In addition, prior to cross-linking, the microgels can be decorated with silver nanoparticles and cross-linked afterwards. Such free-standing nanoparticle hybrid membranes are then used as catalytic systems for the reduction of 4-nitrophenol, which is monitored by UV/Vis spectroscopy.
在本研究中，我们使用基于聚（N-异丙基丙烯酰胺）（PNIPAM）的共聚物微凝胶来制备独立的、可转移的热响应膜。微凝胶通过NIPAM与2-羟基-4-（甲基丙烯酰氧基）-二苯甲酮（HMABP）共聚合成，并旋涂在硅片上。经过随后的紫外线辐射交联后，形成的层很容易从支撑材料上分离。我们获得了横向延伸几毫米、平均层厚几百纳米的独立微凝胶膜。它们可以转移到其他基板上。作为潜在应用的一个例子，我们研究了通过膜的温度依赖性离子传输——电阻测量显示，当达到共聚物微凝胶的较低临界溶液温度时，电阻会急剧且可逆地增加。此外，在交联之前，可以用银纳米颗粒修饰微凝胶，然后进行交联。这种独立的纳米颗粒混合膜随后用作还原4-硝基苯酚的催化体系，并通过紫外/可见光谱进行监测。
