Precision synthesis of polyorganosiloxanes and temporal control over the polymerization process during ring-opening polymerization (ROP) of cyclosiloxanes remain challenging due to the occurrence of side reactions, e.g., intramolecular transfer (backbiting) and intermolecular chain transfer, and irreversible catalyst transformation.
View Article and Find Full Text PDFPhotocatalytic overall splitting of pure water (HO) without sacrificial reagent to hydrogen (H) and oxygen (O) holds a great potential for achieving carbon neutrality. Herein, by anchoring cobalt sulfide (CoS) as cocatalyst and cadmium sulfide (CdS) as light absorber to channel wall of a porous polymer microreactor (PP12), continuous violent H and O bubbling productions from photocatalytic overall splitting of pure HO without sacrificial reagent is achieved, with H and O production rates as high as 4.41 and 2.
View Article and Find Full Text PDFACS Macro Lett
November 2023
Dispersity () as a critical parameter indicates the level of uniformity of the polymer molar mass or chain length. In the past several decades, the development of explicit equations for calculating experiences a continual revolution. This viewpoint tracks the historical evolution of the explicit equations from living to reversible-deactivation polymerization systems.
View Article and Find Full Text PDFPhotocatalytic hydrogen (H ) production is significant to overcome challenges like fossil fuel depletion and carbon dioxide emission, but its efficiency is still far below that which is needed for commercialization. Herein, we achieve long-term stable H bubbling production from water (H O) and lactic acid via visible-light-driven photocatalysis in a porous microreactor (PP12); the catalytic system benefits from photocatalyst dispersion, charge separation, mass transfer, and dissociation of O-H bonds associated with H O. With the widely used platinum/cadmium-sulfide (Pt/CdS) photocatalyst, PP12 leads to a H bubbling production rate of 602.
View Article and Find Full Text PDFUnique structure representation of polymers plays a crucial role in developing models for polymer property prediction and polymer design by data-centric approaches. Currently, monomer and repeating unit (RU) approximations are widely used to represent polymer structures for generating feature descriptors in the modeling of quantitative structure-property relationships (QSPR). However, such conventional structure representations may not uniquely approximate heterochain polymers due to the diversity of monomer combinations and the potential multi-RUs.
View Article and Find Full Text PDFThe past decades have witnessed an increasing interest in developing advanced polymerization techniques subjected to external fields. Various physical modulations, such as temperature, light, electricity, magnetic field, ultrasound, and microwave irradiation, are noninvasive means, having superb but distinct abilities to regulate polymerizations in terms of process intensification and spatial and temporal controls. Gas as an emerging regulator plays a distinctive role in controlling polymerization and resembles a physical regulator in some cases.
View Article and Find Full Text PDFOil/water separation has inspired much research interest because of the damages caused to our natural environment due to oily wastewater. As a leader of advanced separation materials, electrospun polymeric fibrous mats having the properties of special surface wettability, high specific surface area, and high porosity will be a good membrane material for the separation of oily wastewater. Herein, we first prepared pH-responsive polymer poly(dimethylsiloxane)-block-poly(4-vinylpyridine) (PDMS-b-P4VP) mat using electrospinning technology.
View Article and Find Full Text PDFWastewater contaminated with oil or organic compounds poses threats to the environment and humans. Efficient separation of oil and water are highly desired yet still challenging. This paper reports the fabrication of a smart fiber membrane by depositing pH-responsive copolymer fibers on a stainless steel mesh through electrospinning.
View Article and Find Full Text PDFNovel fluorinated gradient copolymer was designed for smart surface with light-responsive controllable wettability and excellent stability. The switchable mechanism and physicochemical characteristics of the as-prepared surface decorated by designed polymeric material were investigated by ultraviolet-visible (UV-vis) spectrum, scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray photoelectron spectroscopy (XPS). Thanks to the functional film and surface roughening, etched silicon surface fabricated by copolymer involving spiropyran (Sp) moieties possesses a fairly large variation range of WCA (28.
View Article and Find Full Text PDFA "schizophrenic" block copolymer (poly[1'-(2-methacryloxyethyl)-3',3'-dimethyl-6-nitrospiro-(2H-1-benzopyran-2,2'-indoline)]-b-poly(acrylic acid) (PSPMA-b-PAA)) was synthesized by sequential copper(0)-mediated living radical polymerization (Cu(0)-mediated LRP) at 30 °C in an oxygen-tolerant system followed by hydrolysis of the resulting polymer. The solvatechromic behaviors of the PSPMA10-b-poly(t-butyl acrylate)40 (PSPMA10-b-PtBA40) and PSPMA10-b-PAA40 block copolymers in organic solvents were investigated by UV-vis spectroscopy. The PSPMA10-b-PtBA40 stabilizes the nonpolar photoisomer and is not sensitive to the polarity of the solvent, while the PSPMA10-b-PAA40 stabilizes the planar zwitterionic form without irradiation.
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