Thin film fabricated from solution-dispersible porous hyperbranched conjugated polymer nanoparticles without surfactants

Advanced Nanostructured Conjugated Microporous Polymer Application in a Tandem Photoelectrochemical Cell for Hydrogen Evolution Reaction

Solar energy conversion through photoelectrochemical cells by organic semiconductors is a hot topic that continues to grow due to the promising optoelectronic properties of this class of materials. In this sense, conjugated polymers have raised the interest of researchers due to their interesting light-harvesting properties. Besides, their extended π-conjugation provides them with an excellent charge conduction along the whole structure. In particular, conjugated porous polymers (CPPs) exhibit an inherent porosity and three-dimensional structure, offering greater surface area, and higher photochemical and mechanical stability than their linear relatives (conjugated polymers, CPs). However, CPP synthesis generally provides large particle powders unsuitable for thin film preparation, limiting its application in optoelectronic devices. Here, a synthetic strategy is presented to prepare nanostructures of a CPP suitable to be used as photoelectrode in a photoelectrochemical (PEC) cell. In this way, electronic and photoelectrochemical properties are measured and, attending to the optoelectronic properties, two hybrid photoelectrodes (photoanode and photocathode) are designed and built to assemble a tandem PEC cell. The final device exhibits photocurrents of 0.5 mA cm^-2 at a 0.7 V in the two electrode configuration and the hydrogen evolution reaction is observed and quantified by gas chromatography, achieving 581 µmol of H₂ in a one-hour reaction.

Construction of dual-functional nitrogen-enriched fluorescent porous organic polymers for detecting m-dinitrobenzene, picric acid and capturing iodine

Two novel nitrogen-enriched porous organic polymers (POPs), HBP and TBP, were constructed via nucleophilic substitution reactions with high nitrogen contents up to 24.91% and 32.92% for sensing to nitroaromatic compounds (NACs) and adsorbing iodine. They were all systematically characterized by solid-state ¹³C NMR, FT-IR, elemental analysis, solid-state UV-Vis, and other material analysis methods. The experimental data proved that both POPs possess high chemical and thermal stability, excellent fluorescence performance, and porous properties with Brunauer-Emmett-Teller (BET) specific surface areas of 32.88 and 68.00 m² g^-1. The two POPs have dual functions of fluorescence sensing and adsorption. On the one hand, due to their excellent conjugated properties and nitrogen-enriched structures, HBP and TBP exhibited incredibly high sensitivity to m-dinitrobenzene (m-DNB) and picric acid (PA) with K_SV values of 2.57 × 10⁵ and 4.93 × 10⁴ L mol^-1 and limits of detection of 1.17 × 10^-11 and 6.08 × 10^-11 mol L^-1, respectively. On the other hand, owing to the plenty of nitrogen affinity sites, they exhibited excellent volatile iodine adsorption with 2.23 and 2.66 g g^-1, respectively.

Two-dimensional conjugated microporous polymer films: fabrication strategies and potential applications

This review describes the latest advances in the preparation and application of two-dimensional conjugated microporous polymers, as well as the future research directions of this field.

Recent advances in polymerizations in dispersed media

Advances in chemistry heterophase polymerizations reflect new developments in polymer chemistry. Although some few polymerization reactions cannot be performed in dispersed media, new polymerization reactions can still benefit from advantages of heterophase reactions, which are fast kinetics due to high local concentration of reagents and advantageous heat exchange. We describe here advances in heterophase polymerizations, with a focus on miniemulsion polymerization, which are mainly driven by academic interest for biomedicine and energy science. Click-reactions in dispersion are particularly interesting because they are bioorthogonals. Synthesis of highly crosslinked polymer colloids, especially with conjugated polymers, has found applications in gas storage, catalysis, and production of energy. Finally, we show how spatial segregation in heterophase polymerization can help to obtain polymer materials with unique structures.

Study of the mechanoluminescence and ‘aggregation-induced emission enhancement’ properties of a new conjugated oligomer containing tetraphenylethylene in the backbone: application in the selective and sensitive detection of explosive

D–π-A based ‘Aggregation-Induced Emission Enhancement (AIEE)’ active conjugated oligomer (oTPETP) exhibits an abnormal blue shifting mechanoluminescence and selective and sensitive detection of explosive.

High-Stability, High-Efficiency Organic Monoliths Made of Oligomer Nanoparticles Wrapped in Organic Matrix

Oligomer nanoparticles (OL NPs) have been considered unsuitable for solid-state lighting due to their low quantum yields and low temperature stability of their emission. Here, we address these problems by forming highly emissive and stable OL NPs solids to make them applicable in lighting. For this purpose, we incorporated OL NPs into sucrose matrix and then prepared their all-organic monoliths. We show that wrapping the OL NPs in sucrose significantly increases their quantum yield up to 44%, while the efficiency of their dispersion and direct solid-film remain only at ∼6%. We further showed ∼3-fold improved temperature stability of OL NP emission within these monoliths. Our experiments revealed that a physical passivation mechanism is responsible from these improvements. As a proof-of-concept demonstration, we successfully employed these high-stability, high-efficiency monoliths as color converters on a blue LED chip. Considering the improved optical features, low cost, and simplicity of the presented methodology, we believe that this study holds great promise for a ubiquitous use of organic OL NPs in lighting and possibly in other photonic applications.

Fiber-optic detection of nitroaromatic explosives with solution-processable triazatruxene-based hyperbranched conjugated polymer nanoparticles

Solution-processable triazatruxene-based hyperbranched conjugated polymer nanoparticles have been developed as homogeneous, transparent fluorescent films coated on glass substrates and on optic-fiber tips for the detection of TNT vapor.

Poly(triphenyl ethene) and poly(tetraphenyl ethene): synthesis, aggregation-induced emission property and application as paper sensors for effective nitro-compounds detection

This paper reports two structurally unique aggregation-induced emission (AIE) polymers that are fully constructed by AIE luminogen tetraphenyl or triphenyl ethene units. Their applications as paper sensors are studied.

Signal enhancement of sensing nitroaromatics based on highly sensitive polymer dots

A new, rapid, sensitive, selective and portable fluorescence detection method for nitroaromatics based on polymer dots (Pdots) had been successfully developed not only in aqueous media but also in the solid state with test strips. The fluorescence quenching rates were proportional to the concentrations of 2,4,6-trinitrophenol (TNP) in the range of 0.2-20.0 μg mL(-1) and p-nitrophenol (PNP) in the range of 0.05-6.0 μg mL(-1), when Pdots were used as ratiometric fluorescent sensors in aqueous solution. The 3σ limit of detection of PNP reached 18.8 ng mL(-1). Compared with polymer-based detection for nitroaromatics in the organic phase, the signal enhancement effect was initially found when Pdots were used to detect nitroaromatics in the aqueous phase. The mechanism of the interaction between Pdots and nitroaromatics was revealed as an electron transfer phenomenon from the electron-rich chromophoric probe to the electron deficient nitroaromatics. The results indicated that Pdots-based detection was particularly suitable for on-site qualitative detection and quantitative analysis of nitroaromatics.

Intramolecular charge-transfer emission from conjugated polymer nanoparticles: the terminal group effect on electronic and optical properties

Efficient tuning of electronic and optical properties of conjugated polymer nanoparticles by intramolecular charge transfer between the core and the terminal groups is demonstrated for the first time.

Fabrication of porous organic polymers in the form of powder, soluble in organic solvents and nanoparticles: a unique platform for gas adsorption and efficient chemosensing

Tetraphenyl-5,5-dioctylcyclopentadiene based porous organic polymers were fabricated in the form of powder, soluble in organic solvents and nanoparticles and were explored for gas adsorption and chemosensing.

Effect of monomer dosing rate in the preparation of mesoporous polystyrene nanoparticles by semicontinuous heterophase polymerization

The semicontinuous heterophase polymerization of styrene in the presence of cross-linking and porogen agents was carried out. Latexes with close to 20% solid content, which contained mesoporous nanoparticles with 28 nm in average diameters, up to 0.5 cm3/g in porosity and 6-8 nm in pore diameters were obtained. By varying the monomer dosing rate over the micellar solution, an unexpected direct dependence of instantaneous conversion on the monomer dosing rate was found. This was ascribed to the higher average number of radicals per particle attained in the polymerization at the higher dosing rate, which in turn would arise from the higher gel percentage in the polymer. It is believed that the cross-linked chains prevent encounters between radicals, delaying the bimolecular termination reactions and allowing the existence of more than one radical inside the particles, which in turn increases the propagation rate.