Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
The precise synthesis of poly(alkenyl boronate)s was achieved through RAFT polymerization of isopropenyl boronate pinacol ester (IPBpin) and subsequent terminal olefination by cobalt catalysis. Experimental and computational investigation on the compatibility of IPBpin with chain transfer agents revealed its conjugated-monomer type behavior that is ascribed to empty p-orbital of boron. Terminal olefination in post-polymerization reaction improved the stability of resulting polymers, enabling the analysis for molecular structure of poly(IPBpin) by MALDI-TOF-MS spectroscopy as well as thermal properties by DSC.
Selective adsorption of trialkylaluminums (R3Al) in modified methylaluminoxane (MMAO) onto crosslinked terpolymer bearing bulky phenoxy groups was performed. The phenoxy groups on the terpolymer can more selectivity react with R3Al than the hydroxy groups on SiO2, and some R3Al was physically adsorbed into the terpolymer. As a result, more efficient removal of R3Al from MMAO solution was achieved. The propylene polymerization using terpolymer-treated MMAO as a cocatalyst was free from chain transfer reaction, which is generally derived from the residual R3Al.
UV light-induced polymerization is one of the most efficient methods to produce pressure-sensitive adhesives in lamination processes, as it is simple and easily scalable. Acrylates and/or methacrylates are typically used as the main components, however, O2 inhibitors are needed, which increases the final cost. In this work, we exploit the oxygen insensitivity of thiol-click reactions, evaluate their potential for use in fast and inexpensive UV curable resins, and demonstrate the design of a formulation with competitive adhesive performance compared to conventional acrylic PSAs.
Alcohol end-functionalized poly(3-hexylthiophene) (P3HT-OH) is a high-value material mainly used for the generation of P3HT-containing block copolymers. However, the synthesis of P3HT-OH has required effort-intensive postpolymerization modifications and additional protecting group techniques. Thus, to overcome the issue, we developed the direct one-pot synthesis of P3HT-OH by Suzuki-Miyaura catalyst-transfer polycondensation. Mild reaction conditions with good functional group tolerance allowed the preparation of well-defined P3HT-OH without protective groups or postmodification processes. Under optimized reaction conditions, low to high molecular weight P3HT-OH can be prepared with high precision and productivity.
Fluoride anions-catalyzed cage scrambling and gelation of POSS-pendant random copolymers was investigated. A series of POSS-pendant random copolymers was prepared using POSS-containing methacrylates and several vinyl monomers. FT-IR, solid-state 29Si-NMR, and swelling experiments of the gelation products showed that the pendant POSS groups underwent intermolecular cage-scrambling reaction, which proceeds via transient siloxane cleavage. Chloride and bromide anions also catalyzed the scrambling reaction under modified reaction conditions. Gelation properties depended on various factors such as the comonomers, reaction solvents, vertex substituents, POSS contents, and catalyst feeds.
In this study, novel water-soluble polyimides and hydrogels were synthesized and evaluated. The water-soluble polyimides were synthesized from biobased 4-aminocinnamic acid dimer and appropriate tetracarboxylic dianhydrides by reaction with aqueous potassium hydroxide. A polyimide hydrogel was prepared using a crosslinking agent with 4-aminophenylalanine or 4-aminocinnamic acid dimer, which are also biobased amino acids, resulted in a fully biobased polyimide hydrogel. This hydrogel exhibits stimulus responsiveness, accompanied by a pH-dependent volume change because of the effect of carboxylate group derived from the polyimide side chain and crosslinking agent.
Surface oxidation method using chlorine dioxide radical (ClO2•) for poly(phenylene sulfide) (PPS) was developed. During the oxidation reaction, sulfonyl groups and sulfite groups were successfully introduced to the surface of the PPS films. The water contact angle of the surface of the PPS film decreased dramatically after the oxidation, indicating that the surface hydrophilicity was improved. Electroless plating demonstrates that typical metals could be tightly deposited on the surface of oxidized PPS film and cannot be removed. This method provides an effective, clean, energy-saving treatment for super engineering plastics.
Near-infrared (NIR) absorptive and emissive poly(p-phenylene vinylene) (PPV)-type π-conjugated polymers based on hypervalent tin-fused azobenzene (TAz) complexes were demonstrated. The synthesized polymers, TAz-PPVs, showed absorption and emission in wavelength regions of >750 and 810 nm in diluted solution, respectively, because of the inherent narrow-energy gap of TAz complexes originating from the three-center four-electron (3c-4e) bond and nitrogen–tin (N–Sn) coordination. Through this research, we revealed that π-conjugated systems including hypervalent bonds were able to expand π-conjugation.
The real-time structural changes of thermoresponsive polymer vesicles upon cooling were investigated by small-angle X-ray scattering and confocal laser scanning microscopy. The disassembly process of the vesicles consists of multiple steps: 1) pore formation, 2) opening and shrinkage of the membrane, and 3) dissolving in the solvent. We also demonstrated that the vesicles can be used as compartments for the controlled release of proteins. This study provides the basis for the mechanism of the disassembly process of thermoresponsive vesicles and a guideline for their use as controlled-release medical devices.
This study presents a simple and general platform for the efficient loading and delivery of proteins using a methoxy-poly(ethylene glycol)-block-poly(L-phosphotyrosine) (mPEG-b-PpY)-templated calcium phosphate (CaP) hybrid nanoparticle. Recombinant proteins bearing a histidine tag can be conveniently loaded onto the hybrid CaP nanoparticles doped with Zn2+ (CaP-Zn) by coordination. Nanoparticle can be protected the protein from proteolytic degradation and effectively delivered to intracellular spaces. This work may open up opportunities for intracellular delivery of recombinant protein therapeutics.
The construction of a deep learning model and visualization of judgment regions were conducted for wide-angle X-ray diffraction and small-angle X-ray scattering images of aliphatic polyesters. The classification models based on convolutional neural networks (CNNs) for the X-ray images to predict the types of polymers and several crystallization temperatures were successively constructed. The judgment regions of the X-ray images used by the CNNs were visualized using the Grad-CAM, LIME, and SHAP methods. This result may contribute to developing important features in deep learning models, such as the recognition of structure–property relationships.
For n-type organic semiconductors, low thermoelectric conversion properties are an issue that needs to be resolved, moreover current manufacturing methods are not compatible with printing technology. In this communication, we report the systematic preparation of carbon nanotube (CNT) sheets containing dopant polymers using a drop-casting method that enhances thermoelectric performance. The inclusion of 1,2-diphenylhydrazine as a secondary dopant significantly improved the ZT value of poly(N-vinyl-2-pyrrolidone)-poly(vinyl alcohol) graft copolymer/CNT, from 5.26 × 10−3 for the undoped system to 1.34 × 10−2. The developed approach, which is expected to provide on-demand manufacturing through printed electronics technologies.
A fluorescent microarray comprising polythiophene-based chemosensors functionalized with pyridinium boronic acid has been developed for the detection of the components of sake such as glucose and pyruvate. The sensor microarray was fabricated on a glass chip for on-site detection utilizing imaging analysis and pattern recognition. The selected four nondiluted sake samples were discriminated by the cross-reactive response pattern. Moreover, the facile chemosensor array realized the prediction of unknown concentrations of glucose and pyruvate in the diluted sake, which indicated its usability for drink analysis.
