School of Physics and Technology, Nanjing Normal University, Nanjing 210000, People's Republic of China.
ACS Appl Mater Interfaces. 2020 Sep 9;12(36):40979-40984. doi: 10.1021/acsami.0c13618. Epub 2020 Aug 25.
Materials with specific wettability properties have aroused enormous interest and research for their broad application prospects in chemical reaction, medical diagnosis, biological analysis, etc. Here, inspired by the unique Janus wettability of lotus leaf and Bragg stacks of beetles, we present a free-standing film with Janus wettability and tunable structural color for water quality monitoring. This film is constructed by using a flexible polymer polyurethane (PU) to pack poly(-isopropyl acrylamide-bis-acrylamide-acrylic acid) (P(NiPAAm-bis-AA))/TiO one-dimensional photonic crystals (1DPCs) into a free-standing state with Janus wettability and tunable structural color. The outer top surface of the film could achieve vivid structural color and a superhydrophobic ability; meanwhile, the outer lower surface could achieve a superhydrophilic ability. Owing to the outstanding pH-sensitive property of the P(NiPAAm-bis-AA), the Janus films could switch its structural color under different pH conditions. This imparts the free-standing film with stability and an antirotation property on the air-water interface. Based on this phenomenon, we have demonstrated a Janus wettability film, together with tunable structural color for water quality monitoring, which gives the bioinspired materials high potential applications in environmental protection.
具有特定润湿性的材料因其在化学反应、医学诊断、生物分析等方面的广泛应用前景而引起了极大的兴趣和研究。在这里，受荷叶独特的双面润湿性和甲虫布拉格堆的启发，我们提出了一种具有双面润湿性和可调结构色的自支撑膜，用于水质监测。该薄膜是通过使用柔性聚合物聚氨酯（PU）将聚（异丙基丙烯酰胺-双-丙烯酰胺-丙烯酸）（P（NiPAAm-bis-AA））/TiO 一维光子晶体（1DPCs）包装成具有双面润湿性和可调结构色的自支撑状态来构建的。薄膜的外顶表面可以实现生动的结构色和超疏水性；同时，外底表面可以实现超亲水性。由于 P（NiPAAm-bis-AA）具有出色的 pH 敏感性，因此 Janus 薄膜可以在不同的 pH 条件下切换其结构颜色。这赋予了自支撑膜在空气-水界面上的稳定性和抗旋转性。基于这一现象，我们展示了一种具有双面润湿性和可调结构色的自支撑膜，用于水质监测，这为仿生材料在环境保护方面的应用提供了巨大的潜力。
