Solid-state intramolecular motions in continuous fibers driven by ambient humidity for fluorescent sensors

Yunmeng Jiang; Yanhua Cheng; Shunjie Liu; Haoke Zhang; Xiaoyan Zheng; Ming Chen; Michidmaa Khorloo; Hengxue Xiang; Ben Zhong Tang; Meifang Zhu

doi:10.1093/nsr/nwaa135

Solid-state intramolecular motions in continuous fibers driven by ambient humidity for fluorescent sensors

Natl Sci Rev. 2020 Jun 17;8(4):nwaa135. doi: 10.1093/nsr/nwaa135. eCollection 2021 Apr.

Authors

Affiliations

¹ State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, International Joint Laboratory for Advanced Fiber and Low-Dimension Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China.
² Department of Chemistry, the Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, and Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
³ Beijing Key Laboratory of Photoelectronic/ Electrophotonic Conversion Materials, Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.

Abstract

One striking feature of molecular rotors is their ability to change conformation with detectable optical signals through molecular motion when stimulated. However, due to the strong intermolecular interactions, synthetic molecular rotors have often relied on fluid environments. Here, we take advantage of the solid-state intramolecular motion of aggregation-induced emission (AIE) molecular rotors and one-dimensional fibers, developing highly sensitive optical fiber sensors that respond to ambient humidity rapidly and reversibly with observable chromatic fluorescence change. Moisture environments induce the swelling of the polymer fibers, activating intramolecular motions of AIE molecules to result in red-shifted fluorescence and linear response to ambient humidity. In this case, polymer fiber provides a process-friendly architecture and a physically tunable medium for the embedded AIE molecules to manipulate their fluorescence response characteristics. Assembly of sensor fibers could be built into hierarchical structures, which are adaptive to diverse-configuration for spatial-temporal humidity mapping, and suitable for device integration to build light-emitting sensors as well as touchless positioning interfaces for intelligence systems.

Keywords: aggregation-induced emission; fibers; humidity sensors; solid-state molecular motion.