Enhancements in Emission and Chemical Resistance of Substituted Acetylene Polymer via in Situ Sol−Gel Reaction in Film

Enhancements in Emission and Chemical Resistance of Substituted Acetylene Polymer via in Situ Sol−Gel Reaction in Fil

Fluorescent Viscosity Sensor Film of Molecular-Scale Porous Polymer with Intramolecular π-Stack Structure

Fluorescent Viscosity Sensor Film of Molecular-Scale Porous Polymer with Intramolecular π-Stack Structur

Fluorescent Viscosity Sensor Film of Molecular-Scale Porous Polymer with Intramolecular π-Stack Structure

Fluorescent Viscosity Sensor Film of Molecular-Scale Porous Polymer with Intramolecular π-Stack Structur

Fluorescent Viscosity Sensor Film of Molecular-Scale Porous Polymer with Intramolecular π-Stack Structure

Fluorescent Viscosity Sensor Film of Molecular-Scale Porous Polymer with Intramolecular π-Stack Structur

Swelling-Induced Emission Enhancement in Substituted Acetylene Polymer Film with Large Fractional Free Volume: Fluorescence Response to Organic Solvent Stimuli

Swelling-Induced Emission Enhancement in Substituted Acetylene Polymer Film with Large Fractional Free Volume: Fluorescence Response to Organic Solvent Stimul

One-Step Synthesis of Hollow Dimpled Polystyrene Microparticles by Dispersion Polymerization

The design and preparation of hollow nonspherical microparticles are of great significance for their potential applications, but the development of a facile synthetic method using only one production step remains a great challenge. In the current work, a new template-free method based on dispersion polymerization was successfully developed to produce anisotropic hollow polystyrene (PS) microparticles in a single step. In the synthesis, ammonium persulfate (APS) played a critical role in the formation and growth of highly uniform and stable hollow PS microparticles. By varying the concentration of APS and that of the stabilizer used, polyvinylpyrrolidone, we were able to control the average size of the PS particles and their degree of concavity. Based on our results and observations, a plausible mechanism for formation of these unusually shaped PS microparticles was proposed

Fluorescence Response of Conjugated Polyelectrolyte in an Immiscible Two-Phase System via Nonelectrostatic Interaction with Surfactants

This paper reports a unique fluorescence (FL) response and diverse applications of conjugated polyelectrolyte (CPE) through nonelectrostatic interaction with appropriate (bio)­surfactants in an immiscible two-phase system. A sulfonated microporous conjugated polymer (SMCP) with a conformation-variable intramolecular stacked structure was used as the CPE film. Despite the extremely high hydrophilicity, the SMCP film responded significantly to the hydrophobic circumstances, either physicochemically or electronically, in the presence of water-in-oil (w/o)-type nonionic surfactants with appropriate hydrophile–lipophile balance (HLB) values. The polymer film became fully wet with hydrophobic solvents due to the addition of small amounts of (bio)­surfactant to reveal remarkable FL emission enhancement and chromism. Microcontact and inkjet printing using the SMCP film (or SMCP-adsorbed paper) and the surfactant solution as substrate and ink, respectively, provided high-resolution FL images due to the distinctive surfactant-induced FL change (SIFC) characteristic. Moreover, the additional electrostatic interaction of SMCP film with oppositely charged surfactants further enhanced the FL emission. Our findings will help comprehensive understanding of the nonelectrostatic SIFC mechanism of CPEs and development of novel SIFC-active materials

Emission Enhancement, Photooxidative Stability, and Fluorescence Image Patterning of Conjugated Polymer Film via <i>in Situ</i> Hybridization with UV-Curable Acrylate Monomers

An acetylene–acrylate polymer hybrid film with enhanced emission, chemical resistance, and photooxidative stability was successfully prepared by the photopolymerization of acrylates in situ in poly[1-phenyl-2-(p-trimethylsilyl)phenylacetylene] (PTMSDPA) film. An acrylate mixture of methyl acrylate (MA) and trimethylol propanetriacrylate (TMPTA) easily diffused into PTMSDPA film, and simultaneously, the emission of the PTMSDPA film significantly increased. Subsequently, when the acrylate-deposited PTMSDPA film was irradiated by UV light at the appropriate irradiation power, the acrylate monomers were readily polymerized in situ in PTMSDPA film. The hybrid film still retained enhanced emission after the photopolymerization. Moreover, the hybrid film hardly dissolved in toluene even after immersing for several minutes, whereas the PTMSDPA film immediately dissolved in toluene. The hybrid film also showed photooxidative stability in air, as compared to the PTMSDPA film, due to the oxygen-blocking effect of the acrylate components. Photomasked UV irradiation of the acrylate-deposited PTMSDPA film led to a highly resolved, fluorescent image pattern on the hybrid film

Solvent-to-Polymer Chirality Transfer in Intramolecular Stack Structure

Solvent-to-polymer chirality transfer was examined using conjugated polymer with intramolecular stack structure (IaSS). When achiral poly­(diphenylacetylene)­s (PDPAs) dissolved in limonene, the solvent chirality was successfully transferred to the side phenyl stack structure, leading to intramolecular axial chirality. The phenyl–phenyl IaSS was under thermodynamic control to readily undergo asymmetric changes in chiral limonene, leading to optical activity in the isotropic structure between the main chain and resonant side phenyl rings. The axial chirality was significantly affected by the chain length and substitution position of the side alkyl groups. The longer alkyl chains and bulkier alkyl group prevented direct intermolecular interactions between the side phenyl rings and the chiral limonene molecules. PDPA with sterically congested, highly stable, and regulated IaSS was not favorable for efficient solvent-to-polymer chirality transfer

Reusable, Ultrasensitive, Patterned Conjugated Polyelectrolyte–Surfactant Complex Film with a Wide Detection Range for Copper Ion Detection

Conjugated polyelectrolytes (CPEs) are emerging as promising materials in the sensor field because they enable high-sensitivity detection of various substances in aqueous media. However, most CPE-based sensors have serious problems in real-world application because the sensor system is operated only when the CPE is dissolved in aqueous media. Here, the fabrication and performance of a water-swellable (WS) CPE-based sensor driven in the solid state are demonstrated. The WS CPE films are prepared by immersing a water-soluble CPE film in cationic surfactants of different alkyl chain lengths in a chloroform solution. The prepared film exhibits rapid, limited water swellability despite the absence of chemical crosslinking. The water swellability of the film enables the highly sensitive and selective detection of Cu2+ in water. The fluorescence quenching constant and the detection limit of the film are 7.24 × 106 L mol–1 and 4.38 nM (0.278 ppb), respectively. Moreover, the film is reusable via a facile treatment. Furthermore, various fluorescent patterns introduced by different surfactants are successfully fabricated by a simple stamping method. By integrating the patterns, Cu2+ detection in a wide concentration range (nM–mM) can be achieved