Dynamic Thermosetting Resins with Synergistic Enhanced Strength and Toughness through Combination with Rigid and Soft Microdomains.

Preparation of materials that possess highly strong and tough properties simultaneously is a great challenge. Thermosetting resins as a type of widely used polymeric materials without synergistic strength and toughness limit their applications in some special fields. In this report, an effective strategy to prepare thermosetting resins with synergistic strength and toughness, is presented. In this method, the soft and rigid microspheres with dynamic hemiaminal bonds are fabricated first, followed by hot-pressing to crosslink at the interfaces. Specifically, the rigid or soft microspheres are prepared via precipitation polymerization. After hot-pressing, the resulting rigid-soft blending materials exhibit superior strength and toughness, simultaneously. As compared with the precursor rigid or soft materials, the toughness of the rigid-soft blending films (RSBFs) is improved to 240% and 2100%, respectively, while the strength is comparable to the rigid precursor. As compared with the traditional crushing, blending, and hot-pressing of rigid or soft materials to get the nonuniform materials, the strength and toughness of the RSBFs are improved to 168% and 255%, respectively. This approach holds significant promise for the fabrication of polymer thermosets with a unique combination of strength and toughness.

Luminescent Perovskite-Cross-Linked Polymer with Low Shrinkage and Excellent Stability.

When organic cross-linked polymers are combined with metal halide perovskite nanocrystals (PNCs) for realizing luminescent perovskite-polymer display materials, the stability of PNCs is enhanced and their shrinkage is suppressed. This work presents a feasible strategy for preparing CsPbBr3 nanocrystals (NCs) within a polydicyclopentadiene (PDCPD) thermosetting cross-linked resin matrix simultaneously via a one-step reaction. The obtained PDCPD@PNCs composite exhibits narrow peak half-widths (15-20 nm), high light transmittance (80%), low curing volume shrinkage (1.4%), tunable tensile properties, excellent stability, and a photoluminescence quantum yield (PLQY) of 44.3%. The composite material exhibits long-term stability in water, acid, and base solutions for over 90 days, with the PL intensity being maintained at over 90%. Furthermore, the composite is highly resistant to polar organic solvents owing to the insolubility imparted by cross-linking. White LEDs (WLED) fabricated using the as-prepared composite demonstrate excellent potential as light sources in optical devices.

Nanofibrous Photocatalytic Membranes Based on Tailored Anisotropic Gold/Ceria Nanoparticles.

The combination of plasmonic nanoparticles with semiconductor photocatalysts is a good strategy for synthesizing highly efficient photocatalysts. Such binary nanoparticles have demonstrated enhanced catalytic activity in comparison to either plasmonic catalysts or semiconductor catalysts. However, problematic recovery and limited long-term colloidal stability of those nanoparticles in suspension limit their wide use in catalysis. To palliate to such limitations, we embedded binary nanoparticles in polymer fibers to design photocatalytic membranes. First, we used the selective over-growth of crystalline cerium oxide on the gold nanoparticle template with distinct shapes. Gold nanospheres, gold nanorods, and gold nanotriangles were used as the template for the growth of the cerium oxide domains. Then, the resulting nanoparticles were used to catalyze model reactions in suspensions. The gold nanoparticles covered with patches of cerium oxide outperformed the fully covered and naked nanoparticles in terms of catalytic efficiency. Finally, the most efficient binary nanostructures were successfully embedded in nanofibrous membranes by colloidal electrospinning and used in water remediation experiments in a flow-through reactor.

Synthesis of temperature, pH, light and dual-redox quintuple-stimuli-responsive shell-crosslinked polymeric nanoparticles for controlled release.

Herein, we prepared a novel quintuple-stimuli-responsive shell-crosslinked (SCL) nanocontainer in respond to temperature, pH, light, and oxidation or reduction species. The well-defined amphiphilic diblock copolymer poly(2-methacryloyloxyethyl ferrocenecarboxylate)-(5-propargylether-2-nitrobenzyl bromoisobutyrate)-poly(dimethylaminoethyl methacrylate) (PMAEFc-ONB-PDMAEMA) was synthesized via atom transfer radical polymerization (ATRP) and click chemistry. The diblock copolymer self-assembled into spherical micelles with a uniform size in aqueous media as non-crosslinked (NCL) micelles, and then the micelles were crosslinked by N,N'-bis(bromoacetyl) cystamine (BBAC) through quaternization reaction between the nitrogen of DMAEMA and the bromine of BBAC to receive the SCL micelles which shrunk at higher temperature, swelled at acidic pH or a low concentration of hydrogen peroxide (H2O2), decrosslinked by a small amount of DL-dithiothreitol (DTT), and were disrupted with DTT and UV light. The multi-stimuli-sensitive properties of the SCL micelles were characterized in detail by dynamic light scattering (DLS), transmission electron microscopy (TEM), fluorescence spectra, and UV-Vis spectra. Owing to the protective effect of the crosslinked network, light response behaviors of the NCL and SCL micelles were different. In contrast to the single stimulus, the combined stimuli could trigger and regulate the release of hydrophobic drug model more effectively and precisely from the SCL micelles. The obtained multi-stimuli-responsive nanocontainers may lead to a new generation of controlled release in the fields of nanotechnology and biotechnology.