Ji Dengxin, Song Haomin, Chen Borui, Zhang Feng, Cheney Alec R, Zhang Nan, Zeng Xie, Atkinson John D, Zhou Chi, Cartwright Alexander N, Gan Qiaoqiang
Department of Electrical Engineering, Department of Industrial and Systems Engineering, and Department of Civil, Structural and Environmental Engineering, The State University of New York at Buffalo, Buffalo, New York 14260, United States.
ACS Omega. 2017 Aug 23;2(8):4838-4844. doi: 10.1021/acsomega.7b00901. eCollection 2017 Aug 31.
Frozen tofu is a famous Asian food made by freezing soft bean curds, which are naturally porous to store flavor and nutrients. When the narrow pores of the soft bean curd are saturated with water and then frozen, pore widths expand to generate a completely new porous structure-frozen tofu has visibly wider pores than the initial bean curd. Intriguingly, this principle can be generalized and applied to manipulate micro/nanopores of functional porous materials. In this work, we will manipulate the pore size of nanoporous polymeric photonic crystals based on the phase change between water and ice. Wet-drying and freeze-drying methods were applied to shrink or expand the pore size intentionally. This principle is validated by directly observing the optical reflection peak shift of the material. Owing to the change in pore size, the reflection peak of the polymeric photonic crystal structure can be permanently, and intentionally, tuned. This simple but elegant mechanism is promising for the development of smart materials/devices for applications ranging from oil/water membrane separations, health monitoring, and medical diagnostics to environmental monitoring, anticounterfeiting, and smart windows.
冻豆腐是一种著名的亚洲食品，由冷冻软豆腐制成，软豆腐天然多孔，可储存风味和营养物质。当软豆腐的细孔充满水然后冷冻时，孔径会扩大，形成一种全新的多孔结构——冻豆腐的孔明显比初始豆腐的孔宽。有趣的是，这一原理可以推广并应用于操纵功能性多孔材料的微/纳米孔。在这项工作中，我们将基于水和冰之间的相变来操纵纳米多孔聚合物光子晶体的孔径。采用湿干法和冷冻干燥法有意缩小或扩大孔径。通过直接观察材料的光反射峰位移来验证这一原理。由于孔径的变化，聚合物光子晶体结构的反射峰可以被永久且有意地调节。这种简单而巧妙的机制对于开发智能材料/设备很有前景，这些应用范围包括油/水膜分离、健康监测、医学诊断、环境监测、防伪和智能窗户等。
