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Enantioselective conjugate addition of azlactones to ethylene sulfonyl fluoride has been achieved via the cooperative catalysis with (DHQD)2PHAL and a hydrogen-bond donor (HBD). This approach furnishes a facile access to a range of structurally diverse azlactone sulfonyl fluoride derivatives with good to excellent yields and enantioselectivities. The combination of azlactone and sulfonyl fluoride group produces valuable unnatural α-quaternary amino acid derivatives for the drug discovery.

An enantioselective Michael addition between N-2,2,2-trifluoroethylisatin ketimines and ethylene sulfonyl fluoride has been disclosed. This method provides a facile strategy to access a range of structurally diverse isatin-derived α-(trifluoromethyl)imine derivatives with excellent yields and enantioselectivities. The intriguing combination of α-(trifluoromethyl)amine and sulfonyl fluoride groups leads to the valuable candidates for the drug discovery.

Recent progress has seen significant advances in the mechanical performances of synthetic hydrogels. However, the mechanics of hydrogels usually suffer drastic degradation under repetitive mechanical and complicated environmental loadings. Here, we fabricate a class of biocompatible layered poly(vinyl alcohol) hydrogels by simply soaking a preformed poly(vinyl alcohol) gel in sodium silicate. The resulting hydrogels exhibit a combination of superior mechanical performances and good biocompatibility, along with exceptional chemical robustness. The layered structure is composed of a compact cover layer and a porous center layer. Both layers are composed of poly(vinyl alcohol). The network in the cover is crosslinked by ordered polarized H-bonds with swelling stability, while the porous center confines a large volume of interstitial water. The structural and crosslinking metric confers the hydrogels with capabilities to tolerate complicated mechanical and environmental loads. The optimized gel is tough (fracture energy >10 kJ m−2) and strong (fracture stress ≈ 5 MPa). The strengthening mechanism can be correlated to the layered structure, which causes the impeded flow of interstitial water. Their mechanical performance is maintained in strong acidic/alkaline, and concentrated electrolytes, and in the presence of salting-in and H-bond-breaking reagents even at elevated temperatures. We speculate that the dipole–dipole pairings of Oδ−–Hδ+⋯ Oδ−–Hδ+ in the cover layer probably generate hydrophobic microdomains. This swelling-resistant interaction may protect the hydrogels from swelling in complex aqueous envrionments. We also discuss the possible mechanism of the formation of layered structures and their crosslinkings.

Multidrug-resistant biofilms are highly resistant to current antimicrobial therapies. We have developed an antimicrobial platform that integrates the bacteria-killing phytochemical carvacrol into dynamically crosslinked polymer nanocomposites (DCPNs). Taking advantage of a reversibly crosslinked Schiff-base scaffold throughout the engineered emulsions, DCPNs exhibited long-term shelf-life and good stability in serum, while readily disassembling in acidic microenvironments. Furthermore, we demonstrated that DCPNs efficiently penetrate the biofilm matrix, eradicating both Gram-negative/positive bacteria enclosed within. Moreover, DCPNs showed no observable toxicity to fibroblast mammalian cells within the same antimicrobial concentrations necessary to eradicate MDR biofilms. Given their potent antimicrobial and stimuli-responsive dissociation characteristics in a biofilm setting, DCPNs are a suitable therapeutic platform for combating MDR bacterial infections.

In order to find a more environmentally friendly flame retardant, we have designed a novel halogen-free flame-retardant (FR) system consisting of ternary and quaternary sulfonates centered on adamantane. They are named 1,3,5-tri(phenyl-4-sodium sulfonate)adamantane (AS3) and 1,3,5,7-tetrakis(phenyl-4-sodium sulfonate)adamantane (AS4), respectively. Both kinds of FRs were synthesized and compounded with polycarbonate (PC) to study their effects on the properties of PC composites. The results show that the new FR system can improve PC flame retardancy efficiently, and has mechanical strength advantages as well. The PC composites with only 0.1 wt% AS3 or 0.08 wt% AS4 can pass vertical burning tests (UL-94) V-0 level, with increasing the value of limiting oxygen index (LOI) to 31.2% or 32.3%. Moreover, they can maintain ideal mechanical properties compared to neat PC simultaneously. Finally, the flame retardant mechanism of this system was verified via thermal analysis, morphology and chemical structure analysis of the char residues.

A series of chiral polysulfonate cyclohexyldiamine-Ni(II) catalysts were prepared via sulfur (VI) fluoride exchange click-reactions. The catalysts exhibited good catalytic activity and enantioselectivity in the Michael addition of malonates to nitroalkenes. The excellent recyclability of the catalysts was demonstrated via the reuse of the privileged catalyst 7a for ten times. The results provide a new strategy for the immobilization of chiral homogeneous catalysts.

Commercially available polystyrene is coupled with self-healability by exploiting a novel healing chemistry of redox cationic polymerization. In this system, iodonium bis(4-methylphenyl) hexafluorophosphate (IBH)/glycidyl methacrylate (GMA) loaded microcapsules and NaBH4 particles are embedded in the matrix through compression molding. The healant is oxygen insensitive and heat resistant so that it meets the requirement of remendable thermoplastics.

In this work, a multilayered microcapsule is proposed and prepared for use in self-healing polymers. Reactants for atom transfer radical polymerization (ATRP) are separately introduced into different places of the microcapsule to construct a latent ATRP reactor. When a polymer containing these capsules is damaged, crack induced breakage of the tiny vessels would lead to contact of the aforesaid reactants and hence autonomous polymerization of the released monomer, so that the damaged portions are re-bonded. The formation of the microcapsules goes through four steps. Optimum synthetic conditions for each step are carefully explored. The experimental results indicate that the components included in the multilayered microcapsules maintain their room temperature reactivity within the time of interest. The single microcapsule-type microreactor is provided with broad applicability as it can work alone with no need for additional chemicals and can be tailor-made according to the requirements of different polymers to be repaired.

Here in this work we propose a thermally molded self-healing thermoplastic polymer containing a multilayer microcapsule-type microreactor. The latter consists of an isolated monomer and catalyst system. As the first proof-of-concept composites, commercial plastics polystyrene (PS) filled with glycidyl methacrylate (GMA)-loaded microreactors are reported. The specially designed structure of the microreactors enables them to be robust enough to survive the thermal processing already widely used in the plastics industry, like melt mixing under shear and compression molding. Upon damage of the composites and microreactors, the GMA monomer is released to the cracks and its atom transfer radical polymerization is triggered when it passes by the catalyst layer. The polymerized GMA serves as a macromolecular adhesive, which not only fills up the interstitial gap of the cracks but also is anchored to the sub-surface of the matrix forming mechanical interlocking, offering satisfactory healing efficiency at room temperature. By changing the species of healing monomer, catalyst and wall substances, the microreactors can meet the versatile requirements of different polymers, so that the approach is provided with broad applicability.