Interfacial Pressure/Area Sensing: Dual-Fluorescence of Amphiphilic Conjugated Polymers at Water Interfaces

Abstract

Exciton migration to emissive defects in π-conjugated polymers is a robust signal amplification strategy for optoelectronic sensors. Herein we report endcapped conjugated polymers that show two distinct emissions as a function of interpolymer distances at the air-water and hydrocarbon-water interfaces. Amphiphilic poly(phenylene ethynylene)s (PPEs) endcapped with perylene monoimides display two distinct emission colors (cyan from PPE and red from perylene), the relative intensity of which depends on the surface pressure applied on the Langmuir monolayers. This behavior produces a ratiometric interfacial pressure indicator. Relative quantum yields are maintained at the different surface pressures and hence display no sign of self-quenching of the excitons in an aggregated state. These polymers can be organized at the micelle-water interface in lytropic liquid crystals, thereby paving the way for potential applications of endcapped amphiphilic conjugated polymers in biosensors and bioimaging.

Rise of Conjugated Poly-ynes and Poly(Metalla-ynes): From Design Through Synthesis to Structure–Property Relationships and Applications

“…Fluorescence switching behavior has also been reported in oligopyridinedecorated 219,222 (vide-infra) and pentiptycene-containing Pt-(II) acetylide complexes 223 as well as in perylene monoimides end-capped oligo-ynes. 224 Amphiphile 130 (Chart 7) displayed two distinct emission colors (cyan from PPE and red from perylene), and the relative emission intensity depends on the surface pressure applied on the Langmuir monolayers. 224 The aqueous solution of lyotropic liquid crystals (LLC) based on 130 was found to be clear and highly emissive with varying colors from cyan to red (Figure 9, panels b and c).…”

Dual Emissions and Thermochromic Luminescence Behavior of Chloroplumbate Organic–Inorganic Hybrid Crystals

“…With respect to other types of sensing techniques, the ratiometric luminescence probe technique shows significant advantages in the aspects of not only improved sensitivity, but also in elimination of the differences in instrumental efficiency, and especially, in complicated analysis systems . Notably, most of the ratiometric luminescence probe materials show dual emissions; moreover, two emission bands display distinct responses to the change of analyte content or environment (e.g., change of temperature or pressure). The change of relative intensity between two emission bands probably results in the distinctive change of the emitted color, which is observable by the naked eye and considered to be a conceivable way to indicate the presence of an analyte or an environmental change .…”

“…Until now, a variety of luminescent organic dyes, quantum dots, coordination polymers (CPs), metal‐organic‐framework (MOFs), and covalent organic framework (COFs) have been developed as the ratiometric luminescence probes for the recognition and sensing of ions/molecules in solution, and molecular species in vapor. However, regarding the study of the detection of widely used analytes, ratiometric luminescence probes have been seldom reported for sensing temperature, the so‐called luminescent thermometer, and for sensing pressure . In contrast to other types of thermometers, a luminescence thermometer possesses unique advantages; for example, fast response, noncontact measurement, nanometric precision, and large‐scale imaging, etc .…”

Amphiphilic Asymmetric Diblock Copolymer with pH-Responsive Fluorescent Properties

“…Fluorescent detecting technology has been widely applied in biological, material, and environmental sciences such as biological imaging, substance detection, and fluorescent switch due to its advantages, including nondestructive detection, selective identification, high sensitivity, and fast response . Fluorescent probes, such as fluorescent proteins, nanoparticles, , organic small molecules, and copolymers can selectively convert microscopic changes into fluorescent signals that can be analyzed and detected.…”