We report for the first time the influence of the particle size of a porous sulfur host on the sulfur utilization and cycling stability of Li–S batteries.
Isophthalate with the simple chemical structure is identified as an effective phosphor for room temperature phosphorescent (RTP) materials. With −Br, −CH 3 , and −CHCH 2 at the 5-position of the benzene ring of didecyl isophthalate, the three crystalline small molecules of DDIP-Br, DDIP-CH 3 , and DDIP-CHCH 2 demonstrate ultralong RTP with lifetime of 236, 650, and 184 ms, respectively, although no specific interactions are recognized in the crystals. Radical polymerization of DDIP-CHCH 2 readily results in Poly-1, which is the first RTP liquid crystalline polymer.Direct attachment of isophthalate phosphor to every repeating unit of polyethylene backbone through a single carbon−carbon bond leads to a significant side-chain jacketing effect, greatly reducing the motion of phosphor moieties. Poly-1 renders a columnar LC phase constructed by parallel packing of the supramolecular column that is composed of two Poly-1 chains. In the column, the isophthalate phosphor is confined in between the core of polymer backbones and the shell of decyl tails, and thus the nonradiative process is further suppressed. The materials design of Poly-1 can be widely applied for developing new RTP polymers.
Long-chain
molecules can self-assemble into ordered and functional
structures through chain folding. In crystalline polymers, chain folding
leads to lamellar crystals that are extremely important to the ultimate
properties. Understanding chain folding at the molecular level remains
a great challenge. Here, we report that a dynamic helical cis-poly(phenylacetylene) bearing a bulky side group (P1), which is a side-chain liquid crystalline polymer, can
also form folded chain lamellae in the hexagonal columnar phase. Our
atomic force microscopy (AFM) experiments on P1 thin
films directly visualized the adjacent and nonadjacent folds at the
liquid crystal–amorphous interface. While the helical segments
of P1 with a diameter of 2.2 nm closely pack in the hexagonal
lattice, the disorder strands that connect the helices could compose
the folds. Furthermore, we monitored the lamellar growth from the
amorphous state using AFM. We demonstrate experimentally for the first
time that the lamellar growth may obey the kinetics of Ostwald ripening.
It is also found that with the initial lamellar thickness close to
the persistence length of P1, the lamellae show simultaneous
lateral extension and thickening.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.