He Jia, Shen Xiuqing, Li Huateng, Yao Ying, Guo Jia, Wang Changchun
State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University, Shanghai 200433, P. R. China.
Laboratory of Advanced Materials, Fudan University, Shanghai 200433, P. R. China.
ACS Appl Mater Interfaces. 2022 Jun 15;14(23):27251-27261. doi: 10.1021/acsami.2c06273. Epub 2022 Jun 3.
In this study, we fabricate a new kind of ultrasensitive humidity-responsive photonic crystal (HPC) films based on emulsion polymerization and the open mill and bending-induced ordering technique (OM-BIOT) method, which is simple and scalable. The HPC film senses relative humidity (RH) from 9 to 98% for the polymer matrix swells up in high RH and shrinks in low RH, leading to a large reflectance shift (81 nm) and distinct color change. Based on the double-peak reflective spectra of the HPC film, we confirm the gradient swelling hypothesis and find that the thickness is another important factor for controlling the sensitivity and response rate of the HPC film. Except for static humidity, the HPC film can also respond to the dynamic humid flow of blowing and polar solvents, which broadens its application potential. This kind of HPC film shows a vivid structural color, and the humidity-responsive behavior is quick, distinct, energy-free, and reversible, having a great prospect for anticounterfeiting application.
在本研究中，我们基于乳液聚合以及开炼机和弯曲诱导有序技术（OM-BIOT）方法制备了一种新型的超灵敏湿度响应光子晶体（HPC）薄膜，该方法简单且可扩展。由于聚合物基体在高湿度下膨胀而在低湿度下收缩，HPC薄膜能够感应9%至98%的相对湿度（RH），从而导致较大的反射率偏移（81 nm）和明显的颜色变化。基于HPC薄膜的双峰反射光谱，我们证实了梯度膨胀假说，并发现厚度是控制HPC薄膜灵敏度和响应速率的另一个重要因素。除了静态湿度外，HPC薄膜还能对吹拂的动态湿气流和极性溶剂作出响应，这拓宽了其应用潜力。这种HPC薄膜呈现出鲜艳的结构颜色，其湿度响应行为快速、明显、无需能量且可逆，在防伪应用方面具有广阔前景。
