Macromolecular Chemistry II and Bayreuth Center for Colloids and Interfaces, Universität Bayreuth, Universitätsstraße 30, 95440, Bayreuth, Germany.
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China.
Macromol Rapid Commun. 2018 May;39(10):e1800082. doi: 10.1002/marc.201800082. Epub 2018 Apr 20.
In this paper, preparation method and actuation properties of an innovative composite membrane composed of thermo- and pH-responsive poly(N-isopropylacrylamide-co-acrylic acid) fibers (average diameter ≈ 905 nm) embedded within a passive thermoplastic polyurethane (TPU) matrix at different angles with degree of alignment as high as 98% are presented. The composite membrane has a gradient of TPU along the thickness. It has the capability of temperature- and pH-dependent direction-, and size-controlled actuation in few minutes. The stresses generated at the responsive fiber and nonresponsive matrix provide actuation, whereas the angle at which fibers are embedded in the matrix controls the actuation direction and size. The temperature has no effect on actuation and actuated forms at pH 7 and above, whereas the size of the actuated forms can be controlled by the temperature at lower pH. The membranes are strong enough to reversibly lift and release ≈426 times weight of their own mass (2.47 g metal ring is lifted by a 5.8 mg membrane). Soft actuators are of interest as smart scaffolds, robotics, catalysis, drug release, energy storage, electrodes, and metamaterials.
本文介绍了一种创新的复合膜的制备方法和驱动特性，该复合膜由热响应和 pH 响应的聚（N-异丙基丙烯酰胺-co-丙烯酸）纤维（平均直径约为 905nm）组成，嵌入在具有高达 98%的高度取向度的被动热塑性聚氨酯（TPU）基质中，以不同的角度排列。复合膜在厚度上具有 TPU 的梯度。它具有在几分钟内进行温度和 pH 依赖性的方向和尺寸控制驱动的能力。在响应纤维和非响应基质之间产生的应力提供了驱动，而纤维在基质中的嵌入角度控制了驱动的方向和尺寸。在 pH 值为 7 及以上时，温度对驱动和驱动形式没有影响，而在较低的 pH 值下，可以通过温度来控制驱动形式的尺寸。这些膜足够坚固，可以可逆地举起并释放自身质量约 426 倍的重量（由 5.8mg 的膜举起 2.47g 的金属环）。软致动器作为智能支架、机器人技术、催化、药物释放、能量存储、电极和超材料很有吸引力。
