Direct C-H Arylation Derived Ternary D-A Conjugated Polymers: Effects of Monomer Geometries, D/A Ratios, and Alkyl Side Chains on Photocatalytic Hydrogen Production and Pollutant Degradation.

Donor-acceptor (D-A) conjugated polymer (CP) featuring high charge mobility and widely tunable energy bands have shown promising prospects in photocatalysis. In this work, a library of ternary D-A CPs (22 polymers) based on benzothiadiazole, bithiophene, and fluorene derivatives (i.e., fluorene [Fl], 9,9-dihexylfluorene [HF], and 9,9'-spirobifluorene [SF]) with and without alkyl side chains, and with 3D geometry are designed and synthesized via atom-economical direct C-H arylation polymerization to explore the synergetic effects of stereochemistry, D/A ratio, and alkyl chains on the properties and photocatalytic performances, which reveal that 1) the cross-shaped 3D spirobifluorene (SF) building block shows the highest hydrogen evolution rates (HER) owing to the sufficient photocatalytic active sites exposed, 2) the alkyl-free linear polymer (FlBtBT0.05 ) exhibit the highest photocatalytic pollutant degradation performance owing to its superior charge separation, and 3) the alkyl side chains are redundances that will exert detrimental effects on the aqueous photocatalysis owing to their insulating and hydrophobic property. The structure-property-performance correlation results obtained will provide a desirable guideline for the rational design of CP-based photocatalysts.

Renewable plant-derived lignin for electrochemical energy systems.

Lignin, as one of the most abundant natural polymers, has been proved to be a promising material for the construction of high-performance electrochemical energy systems, including electrodes, electrolytes, and separators, because of their low-cost and sustainable natures and unique structure with abundant functional group. In this review article, we outline some key contributions in this field such as fundamental principles and various electrochemical energy systems including rechargeable batteries, supercapacitors, solar cells, and fuel cells. At the same time, we also point out the significant scientific discussion and critical barriers for lignin-based materials for electrochemical energy systems and also provides feasible strategies for preparing new sustainable energy materials.

Multifunctional phototheranostic nanoplatform based on polydopamine-manganese dioxide-IR780 iodide for effective magnetic resonance imaging-guided synergistic photodynamic/photothermal therapy.

Multifunctional phototheranostics combining diagnostic and therapeutic modalities may provide a revolutionary opportunity for cancer treatment. As a promising tumor phototheranostic molecule, IR780 iodide (IR780) shows excellent photodynamic and photothermal performance under near-infrared laser irradiation; however, its hydrophobicity and instability limit its further use in organisms. This work demonstrates the design and development of a multifunctional nanoplatform (PMIDA, referring to polydopamine (PDA)-manganese dioxide (MnO2)-IR780) for imaging-guided phototherapy. The good biocompatibility of PDA greatly improves the water solubility and photostability of IR780, and its excellent photothermal properties make PMIDA a dual photothermal therapy (PTT). MnO2-induced generation of oxygen in the tumor microenvironment improves the hypoxia effect and photodynamic therapy (PDT) of IR780. Moreover, Mn2+ serves as a decent T1-weighted magnetic resonance imaging (MRI) probe to guide treatment. Notably, in relevant cellular assays, PMIDA shows high photodynamic and photothermal effects contributing to the final therapeutic effect. The MRI-guided PDT/PTT synergistic therapy effect in vivo is demonstrated by precise tumor diagnosis and complete tumor elimination outcomes. Based on these experiments, PMIDA nanoparticles display promising effects in facilitating intravenous injection of IR780 and achieving magnetic resonance imaging (MRI)-guided phototheranostic efficacy for tumor treatment.

Size-Controlled and Super Long-Term Stable Lignin Nanospheres through a Facile Self-Assembly Strategy from Kraft Lignin.

In diverse fields, much attention has been concentrated on the preparation of lignin nanospheres with various structures. Here we report a facile self-assembly strategy for preparing super long-term stable hollow and solid nanospheres based on lignin fractionation. We found that different lignins obtained at different pHs during fractionation can form nanospheres with different particle sizes and structures. The self-assembled and formation mechanisms of the nanospheres were surveyed by dynamic light scattering (DLS), elemental analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The analysis results showed that the phenolic hydroxyl groups and the intermolecular π-π interaction play a decisive effect in the formation of nanospheres. This study can not only facilitate the advance of lignin-based nanotechnologies but also provide a broad prospect for the use of black liquor.