Covalently cross-linked polymers have many technological applications for their excellent properties, but they suffer from the lack of processability and adaptive properties. We report a simple, efficient method of generating adaptive cross-linked polymers via olefin metathesis. By introducing a very low level of the Grubbs' second-generation Ru metathesis catalyst, a chemically cross-linked polybutadiene network becomes malleable at room temperature while retaining its insolubility. The stress relaxation capability increases with increasing level of catalyst loading. In sharp contrast, catalyst-free control samples with identical network topology and cross-linking density do not show any adaptive properties. This chemistry should offer a possibility to combine the dimensional stability and solvent resistance of cross-linked polymers and the processability/adaptibility of thermoplastics.

In this article, we demonstrate transition-metal-catalyzed olefin metathesis as a simple, effective method for healing polymers via dynamic exchange of strong carbon-carbon double bonds. Upon introducing a very low level of the Grubbs' second-generation Ru metathesis catalyst into cross-linked polybutadiene (PBD) network, the material self-heals effectively at various conditions under moderate pressures. In sharp contrast, catalyst-free control samples with identical network topology and cross-linking density show minimal healing. The healing efficiency of the materials was carefully investigated under different concentrations of the Ru catalyst, compression pressures, and temperatures. It is demonstrated for the first time that a bulk polymer could effectively heal via dynamic covalent bond formation at sub-ambient temperature. The Ru-loaded PBD samples not only heal well with themselves but also with control samples without any catalyst. Furthermore, a completely Ru-free PBD network can heal effectively upon simply applying a very small amount of Ru catalyst only at the fracture surface. The simplicity and effectiveness of this self-healing approach make it potentially applicable to a wide range of olefin-containing polymers.

Perovskite quantum dots (PeQDs) have been regarded as an alternative to traditional phosphor color converters in the backlit display to improve the color gamut and rendition of LCD. However, the pending barriers of aggregation quenching and structure instability are hindering their practical applications. Herein, high-quality CsPbX3 (X = Br, Br/I) PeQDs were in situ precipitated inside glass to produce nanocomposites with superior optical performance and stability. The highest photoluminescence quantum yield (PLQY) of ∼100% for CsPbBr3@glass is ascribed to the elimination of the inner filter effect via a physical dilution approach to restore its apparent value to an intrinsic one, and the exceptional photostability and water/heat resistance are benefited from their effective isolation from the external environment by the surrounding glass network units. Employing the PeQDs@glass@PDMS monolithic film, a high-performance backlit LCD was designed, and its color gamut reached 152% of commercial LCD and 103% of NTSC, demonstrating a great potential in the optoelectronic industry.

Inspired by arylamide-based oligomeric foldermers that are stabilized by intramolecular hydrogen bonding, a series of polyamides with intramolecular hydrogen-bonding motifs were synthesized via polycondensation reactions. These polymers can fold into helical conformation different from their linear control. The chirality of helical conformation can further be tuned via acid-base complexation using chiral residues.

A novel family of giant pi-conjugated dendrimers (G0, G1, and G2) solely constructed by 5,5,10,10,15,15-hexahexyltruxene units has been developed in a convergent manner through a Suzuki cross-coupling reaction. The overall yields to such large rigid conjugated dendrimers are quite satisfying. The structures and purity of these nanosize rigid dendrimers are verified by 1H and 13C NMR, MALDI-TOF MS, and elemental analysis.