Synthesis of Arylene Ether-Type Hyperbranched Poly(triphenylamine) for Lithium Battery Cathodes

We synthesized a new poly(triphenylamine), having a hyperbranched structure, and employed it in lithium-ion batteries as an organic cathode material. Two types of monomers were prepared with hydroxyl groups and nitro leaving groups, activated by a trifluoromethyl substituent, and then polymerized via the nucleophilic aromatic substitution reaction. The reactivity of the monomers differed depending on the number of hydroxyl groups and the A2B type monomer with one hydroxyl group successfully produced poly(triphenylamine). Based on thermal, optical, and electrochemical analyses, a composite poly(triphenylamine) electrode was made. The electrochemical performance investigations confirmed that the lithium-ion batteries, fabricated with the poly(triphenylamine)-based cathodes, had reasonable specific capacity values and stable cycling performance, suggesting the potential of this hyperbranched polymer in cathode materials for lithium-ion batteries.

Enhancing Toughness and Impact Strength of Epoxy Resins by Using Hyperbranched Polymers

Toughened epoxy has been widely used in industrial areas such as automotive and electronics. In this study, nanosized hyperbranched polymers (HBPs) as a flexibilizer are synthesized and embedded into epoxy resin to enhance the toughness and flexibility. Two different HBPs, hyperbranched poly(methylacrylate-diethanolamine) (poly(MA-DEA)) and poly(methylacrylate- ethanolamine) (poly(MA-EA)), were prepared and blended with both epoxy and polyetheramine, a curing agent. The molecular size of HBPs was estimated to be 6 ~ 14 nm in diameter. The molecular weight of HBPs ranges from 1500(1.5 K) to 7000(7.0 K) g/mol. In cured epoxy/HBP blends, no phase separations are occurred, indicating that HBPs possess sufficient miscibility with epoxy. The tensile toughness of the blends increased with changing the molecular weight of HBPs without sacrificing tensile strengths. The impact strength of the blends increases stiffly until the loading % of HBPs in the blends reaches 10 wt%. In addition, the experimental studies showed that impact resistance also increased with an increase in molecular weight of HBPs. The obtained impact resistance of the epoxy/HBP blends with 10 wt% was 270% more effective compared to that of cured neat epoxy.

A Reduction Active Theranostic Nanoparticle for Enhanced Near-Infrared Imaging and Phototherapy by Reducing Glutathione Level in Cancer Cells

Facile preparation of a tumoral-stimuli-activated theranostic nanoparticle with simple constituents remains a challenge for tumor theranostic nanosystems. Herein we design a simple reductionresponsive turn-on theranostic nanoparticle for achieving fluorescent imaging and phototherapy combination. The theranostic nanoparticle is prepared by a simple one-step dialysis method of reduction active amphiphilic hyperbranched poly(β-amidoamines) and a near-infrared (NIR) dye indocyanine green (ICG). The fluorescence of ICG is quenched by the aggregation-caused quenching (ACQ) effect. The fluorescent intensity of free ICG at 816 nm was ∼40 times as high as that of particulate ICG. After reductive nanoparticles incubated with dithiothreitol (DTT), the size of the nanoparticles increased from 160 nm to 610 nm by Dynamic light scattering (DLS). As nanoparticles were internalized by cancer cells, the disulfide bonds would be cleaved by intracellular reduction agents like glutathione (GSH), leading to the release of entrapped ICG. The released ICG regained its fluorescence for self-monitoring the release and therapeutic effect of ICG by fluorescence spectra and the quantitative evaluation of NIR fluorescence intensity. Remarkably, nanoparticles can also reinforce antitumor efficacy through photodynamic therapy and GSH depletion property. This study provides new insights into designing turn-on theranostic systems.