b S Supporting Information' INTRODUCTION Fluorescent materials with protein sensing capability are of scientific significance and economic interest because of their vial applications ranging from proteomics, to medical diagnostics, and to pathogen detection. 1 Owing to their higher structural complexity and environmental sensitivity relative to other biomolecules, effective protein sensing materials should not only bear appropriate receptors for efficient binding with target proteins but also possess perturbable functionalities for sensitive transduction of recognition events. 2 Conjugated polyelectrolytes (CPEs) composed of π-conjugated fluorescent backbones with amenable water-soluble side chains well fulfill these requirements. 3 For instance, the electron-delocalized backbones of CPEs facilitate rapid intrachain and interchain exciton migrations, bringing in amplified signals and improved sensitivity as compared to small fluorophores, 4 while their numerous charged side chains along fluorescent backbones orchestrate their electrostatic behaviors in aqueous media, resulting in efficient multiple interactions with proteins. CPEs thus hold great promise in protein sensing. 5 Fluorescent quenching, 6 colorimetric, 7 and fluorescence resonance energy transfer (FRET) properties 8 of CPEs have been utilized for protein detection. In comparison with fluorescence quenching and colorimetric assays, FRET-based sensing strategy has the unique advantage of dual-channel signal collection, consequently leading to reduced possibility of false-positive signals. 9 Array-based and specific proteins assays have been developed by taking advantage of distance-sensitive FRET between CPEs and dye-labeled probes. Recently, label-free FRET protein assays have also been developed using CPEs with energy donorÀacceptor architecture. 10 The working mechanism relies on the hypothesis that three-dimensional interchain FRET is more efficient than one-dimensional intrachain FRET due to the stronger electronic coupling of the former. 11 Upon CPE/ protein complexation, polymer aggregation occurs to favor FRET from the donor segments to the acceptor units, giving to fluorescent color variation. The efficiency of such aggregationenhanced FRET is strongly dependent on the nature of proteins such as net charges, inorganic components, and hydrophobicity, consequently making protein discrimination possible.Despite the usability of aggregation-enhanced FRET for protein sensing, CPEs with energy donorÀacceptor architecture ABSTRACT: Cationic conjugated polyelectrolytes (CPEs) containing an iridium complex ((ppy) 2 Ir(FlPy)) as the energy acceptor were synthesized via Suzuki coupling reaction. The polymer with 12 mol % (ppy) 2 Ir(FlPy) (P4) shows efficient intrinsic fluorescence resonance energy transfer (FRET) in aqueous solution due to the solubility-limitation-caused polymer aggregation. Thus, at a relatively high concentration, P4 emits dual-emissive red phosphorescence upon donor excitation. Investigation of the emission responses of P4 toward pr...

Superhydrophobic and oleophilic sponges have been demonstrated as promising candidates for oil/water separation. However, there are still challenges in large-scale fabrication of superhydrophobic sponges with low cost and feasible method for industrial applications. Herein, we report a superhydrophobic and oleophilic melamine sponge functionalized by a uniform polydimethylsiloxane (PDMS) film that can be easily coated onto the sponge skeleton through UV-assisted thiol–ene click reactions. The PDMS films are characterized by a hierarchically striped microstructure with an average distance less than 2 μm. Because of the striped microstructure and the hydrophobic property of silicone, a high contact angle of 156.2° was achieved. Importantly, the interconnected open-cell structure of the melamine sponge was preserved by adapting the thickness of the PDMS film. The PDMS-coated melamine sponge exhibited a desirable absorption capacity of 103–179 times its own weight with oils and organic solvents. The excellent mechanical properties of melamine and the flexibility of PDMS enable the PDMS-coated melamine sponges to be squeezed repeatedly without collapsing. This study offers a robust and effective approach in large-scale preparation of a superhydrophobic sponge for large-scale oil spill containment and environmental remediation by the inexpensive commercial polymethylvinylsilicone and facile dip-coating/UV-curing method.

The photoinduced solid-to-liquid transitions property of azobenzene-containing polymers (azopolymers) enables azopolymers with various promising applications. However, a general lack of knowledge regarding the influence of structure of the azobenzene derivatives on the photoinduced liquefaction hinders the design of novel azopolymers. In the present study, a series of azopolymers with side chains containing azobenzene unit bearing alkyl electron-donating groups were synthesized. The photoisomerization and photoinduced liquefaction properties of newly synthesized azopolymers were investigated. Alkyl-based electron-donating group significantly facilitate the photoisomerization process of azopolymers in solution, as the electron-donating ability of substituents increased, the time required for photoisomerization of azopolymers continually deceased. Meanwhile, the electron-donating group can drastically accelerate photoinduced solid-to-liquid transitions of azopolymers, the liquefaction rate of obtained azopolymers gradually getting quicker as the electron-donating ability of substituents increased. This study clearly demonstrates that the electron-donating group that bearing in the azobenzene group of polymer side chain play an essential role on the photoinduced solid-to-liquid transitions of azopolymers, and hence, gives an insight into how to design novel azopolymers for practical applications.

A series of rosin‐based cationic gemini surfactants with different spacer length (n = 2, 3, 4) were synthesized and characterized. Surface activity and micellization parameters including the critical micelle concentration, the degree of counterion dissociation, and thermodynamic functions of micellization in aqueous solutions have been investigated. Free energy perturbation was performed to study the enthalpy‐entropy compensation of the synthesized gemini surfactants in aqueous solutions. The experimental results showed that the micellization of rosin‐based gemini surfactants in aqueous solutions is a spontaneous and entropy‐driven process. The micellization process was found to follow the entropy–enthalpy compensation phenomenon.

In situ studies of the aggregation behavior of traditional surfactants at the liquid interface using spectroscopic methods are often significantly affected by the large volume of fluorescent groups, such as pyrene. Fluorescent‐Gemini surfactants provide an ideal solution since the fluorescent block can be designed as a spacer or a tail. In this work, we report the synthesis of a new fluorescent‐Gemini surfactant with a rigid spacer (referred to as 8‐TBT‐8). The aggregation behavior and application in cell‐membrane imaging were investigated. The unique aggregation behavior in an organic solvent and aqueous solution was studied using spectroscopy. UV–vis and photoluminescence spectra of 8‐TBT‐8 revealed that this new fluorescent surfactant forms H aggregates in organic solution to give blue emission, whereas it forms J aggregates in aqueous solution to give green fluorescence under UV light. In addition, the fluorescence intensity of 8‐TBT‐8 increases abruptly at concentrations higher than the critical micellization concentration. Good photostability and a unique structure make the synthesized Gemini surfactant very suitable for membrane imaging.