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

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 interface for intelligence systems.

Enantiomeric Switching of the Circularly Polarized Luminescence Processes in a Hierarchical Biomimetic System by Film Tilting

“…For example, a high quantum yield (Φ F ) of 54.2% was obtained by incorporating TPE-EP into crystallized PLLA, which is significantly higher in comparison to the pristine dye powder (Φ F = 41.0%). The highest enhancement could be achieved with more than 2-fold emission efficiency improvement, which might be due to the increased rigidity and restricted intramolecular motions of AIEgens that were confined in between twisted crystallites. ,, Moreover, the solid, continuous, and flexible crystalline PLLA films with stable optical performance can also survive mechanical deformation, which would broaden the photonic applications.…”

Smart Fibers and Textiles for Personal Health Management

“…52,63 Figure 3D shows an integrated fiber that combines a printed fiber-shaped temperature sensor with a printed fiber-shaped asymmetric supercapacitor. 52 Some fibers containing hydrophilic polymers, 64 graphene, or carbon nanotubes (CNTs) 58 ultrasensitive all-textile airflow sensor (Figure 3E) that could be used for detecting airflow and protecting people from potential risk. 49 With the development of advanced materials and manufacturing techniques, fibers and textiles with communication or multifunctional sensing capabilities are becoming increasingly attractive.…”

“…Because fiber conductivity can change with varying temperature, conductive fibers and textiles can be used as temperature sensors. , Figure D shows an integrated fiber that combines a printed fiber-shaped temperature sensor with a printed fiber-shaped asymmetric supercapacitor . Some fibers containing hydrophilic polymers, graphene, or carbon nanotubes (CNTs) can show changes in conductivity upon exposure to environments with different humidity and can therefore work as humidity sensors. In addition, inspired by spiders’ fluff, Wang et al .…”

Fibrous aggregates: Amplifying aggregation-induced emission to boost health protection

“…Fibers, especially synthetic polymer fibers, characterized with high aspect ratio and high surface area [ 25 , 26 ], is a kind of long and thin thread of material that could be knit or woven into a fabric [ 27 , 28 ]. The fluorescent probes are directly embedded into or grafted onto fibers, showing high interface to interact with analytes and thereby exhibiting high sensitivity and fast responsibility, which may have a synergistic effect with polymer matrix [ 29 , 30 ]. Fibrous-based fluorescent sensors are easy-readable, sensitive and flexible to conveniently integrate into portable devices [ 31 ], benefitting for family and individual self-testing.…”