Chi-How Peng

A series of tralen‐based organometallic complexes incorporating zinc(II), calcium(II), and nickel(II) were synthesized and used for controlling the radical polymerization of vinyl acetate (VAc), N ‐vinylpyrrolidone (NVP), acrylonitrile (AN), and methyl acrylate (MA). The resulting polymerizations demonstrated living characteristics, including linear increases in molecular weight with monomer conversion, molecular weight matching the theoretical values, and the formation of block copolymers. The mechanism studies, supported by NMR spectrum, MALDI‐TOF MS data, and chain extension experiments, indicate that the control of polymerization is governed by a degenerative transfer pathway, with the reactive sites at the γ‐carbon of tropone moieties. The control experiment using EDTA to extract the metal ions from the polymer products confirmed that the polymer chain is bound to the ligand rather than the metal center. This establishes tralen as a non‐innocent ligand that participates in the radical deactivation process.

We have synthesized on-demand degradable hydrogels that firmly attach to porcine skin and are easily removed by using l -cysteine solution.

A stable organic molecule, 4-nitrophenylacetylene, is used as a recyclable photo-initiator for the polymerization of aqueous monomers in water under ambient conditions.

A new strategy, troponoid-mediated radical polymerization, has been applied to the radical polymerization of N-vinylpyrrolidone (NVP), 2-hydroxyethyl acrylate (HEA), and N,N-dimethyl acrylamide (DMA) in aqueous media. The observed living characteristics including the linear increase in molecular weight with monomer conversion and the formation of block copolymers demonstrate the effectiveness of troponoids in controlling radical polymerization in water, but the relatively high dispersity (Đ) implied that the polymerization is partially controlled. Tropone (TP) and its derivatives, tropolone (TP-OH), 2-chlorotropolone (TP-Cl), and 2-methoxytropolone (TP-OMe) were employed to optimize the reaction conditions. The versatility of this approach is further highlighted by the synthesis of PDMA-b-PVP and PHEA-b-PVP block copolymers. Mechanistic insights and kinetic parameters were elucidated through NMR analysis, chain extension experiments, UV/Vis spectroscopy, and computational simulation.

Accurate prediction of polymer-solvent interactions is essential for applications such as polymer processing, drug delivery, and membrane separations. The Flory-Huggins interaction parameter (χ parameter) serves as a key descriptor for polymer-solvent compatibility; however, its experimental determination is often costly and time-consuming. In this study, we develop a machine learning framework based on Directed Message Passing Neural Networks (D-MPNNs) to predict χ parameters directly from molecular structures, temperature, and volume fraction. Our approach systematically evaluates different feature representations, pooling methods, and empirical equation integrations to optimize prediction accuracy. Among the tested models, D-MPNN-TC, which incorporates both temperature and volume fraction, demonstrates strong predictive performance (MAE = 0.092, RMSE = 0.162, R² = 0.926), outperforming descriptor-based models that rely on precomputed molecular fingerprints and handcrafted chemical features. Additionally, integrating the Flory-Huggins equation into the classification framework enables highly accurate miscibility predictions, with F1 scores of 0.915. Further analysis using t-SNE visualization reveals that D-MPNNs effectively capture key structural features, such as aromaticity and cyclic structures, that influence polymer-solvent interactions. Our findings highlight the advantages of graph-based molecular representations over traditional fingerprinting methods and underscore the importance of volume fraction information in predicting polymer-solvent compatibility. This study provides a scalable and interpretable framework for leveraging machine learning in polymer science, facilitating data-driven solvent selection and polymer design.

The emulsion polymerization of vinyl acetate (VAc) is carried out in an aqueous medium containing the anionic surfactant of sodium dodecyl sulfate (SDS) and various troponoids, including tropone (TP), tropolone (TP‐OH), 2‐chlorotropolone (TP‐Cl), and 2‐methoxytropolone (TP‐OMe). This method yields stable latexes of PVAc with characteristics of reversible‐deactivation radical polymerization (RDRP), including predictable molecular weight, smooth shifts in the GPC traces, and molecular weight consistent with the theoretical values. Additionally, block copolymers of poly(vinyl acetate)‐block‐poly(methyl acrylate) (PVAc‐b‐PMA) are prepared and exhibited remarkable stretchability, achieving a strain of 1507% when cast into a film. This innovative RDRP technique offers an environmentally friendly approach for generating PVAc‐based block copolymers suitable for advanced materials applications and potential large‐scale production.