Mussel-Inspired Adhesive Binders for High-Performance Silicon Nanoparticle Anodes in Lithium-Ion Batteries

Myung-Hyun Ryou, Jangbae Kim, Inhwa Lee, Sunjin Kim, You Kyeong Jeong, Seonki Hong, Ji Hyun Ryu, Taek-Soo Kim, Jung-Ki Park,Haeshin Lee,Jang Wook Choi

Conjugation of mussel-inspired catechol groups to various polymer backbones results in materials suitable as silicon anode binders. The unique wetness-resistant adhesion provided by the catechol groups allows the silicon nanoparticle electrodes to maintain their structure throughout the repeated volume expansion and shrinkage during lithiation cycling, thus facilitating substantially improved specific capacities and cycle lives of lithium-ion batteries.

Efficient Metathesis of Terminal Alkynes

 

Dipl.-Chem. Birte Haberlag, Dr. Matthias Freytag, Dr. Constantin G. Daniliuc, Prof. Dr. Peter G. Jones, Prof. Dr. Matthias Tamm

Now even terminal: The 2,4,6-trimethylbenzylidyne complexes [MesC M{OC(CF3)2Me}3] (M=Mo, W) were synthesized from [Mo(CO)6] and [W(CO)6], respectively. The molybdenum complex is an efficient catalyst for the metathesis of internal and terminal alkynes and also for the ring-closing metathesis of internal and terminal α,ω-diynes at room temperature and low catalyst concentrations.

Surface-Induced Hydrogelation Inhibits Platelet Aggregation

Wenting Zheng †, Jie Gao †, Lijie Song †, Chongyi Chen §, Di Guan †, Zhihong Wang †, Zhibo Li *§, Deling Kong *†, and Zhimou Yang *†

We demonstrate that a tripeptide hydrogelator, Nap-FFG, can selectively self-assemble at the surface of platelets, thus inhibiting ADP-, collagen-, thrombin- and arachidonic acid (AA)-induced human platelet aggregations with the IC50 values of 0.035 (41), 0.14 (162), 0.062 (68), and 0.13 mg/mL (148 μM), respectively. Other tripeptide hydrogelators with chemical structures of Nap-FFX (X = A, K, S, or E) could not or possessed less potencies to inhibit platelet aggregations. We observed higher amounts of Nap-FFG at the platelet surface by the techniques of LC-MS and confocal microscopy. We also observed self-assembled nanofibers around the platelet incubated with the Nap-FFG by cryo-TEM. The ζ potential of Nap-FFG treated platelets was a little bit more negative than that of untreated ones. The amount of Nap-FFG at the surface of NIH 3T3 cells was much less than that of platelets. These observations suggested that Nap-FFG could selectively self-assemble through unknown ligand–receptor interactions and form thin layers of hydrogels at the surface of platelets, thus preventing the aggregation of them. This study not only broadened the application and opened up a new door for biomedical applications of molecular hydrogels but also might provide a novel strategy to counteract infection diseases through selective surface-induced hydrogelations at pathogens, such as bacteria and virus.

Glycans pattern the phase behaviour of lipid membranes

Hydrated networks of glycans (polysaccharides)—in the form of cell walls, periplasms or gel-like matrices—are ubiquitously present adjacent to cellular plasma membranes1, 2, 3, 4. Yet, despite their abundance, the function of glycans in the extracellular milieu is largely unknown5. Here we show that the spatial configuration of glycans controls the phase behaviour of multiphase model lipid membranes: inhomogeneous glycan networks stabilize large lipid domains at the characteristic length scale of the network, whereas homogeneous networks suppress macroscopic lipid phase separation. We also find that glycan-patterned phase separation is thermally reversible—thus indicating that the effect is thermodynamic rather than kinetic—and that phase patterning probably results from a preferential interaction of glycans with ordered lipid phases. These findings have implications for membrane-mediated transport processes6, 7, 8, potentially rationalize long-standing observations that differentiate the behaviour of native and model membranes9, 10, 11, 12, 13 and may indicate an intimate coupling between cellular lipidomes and glycomes.

Liquid-crystal polymers: Exotic actuators

Three-dimensional ordering in liquid-crystalline polymers is induced by the photopolymerization of a mixture of mesogens sandwiched between two patterned substrates. By incorporating an infrared-sensitive dye in the mixture, polymer films that undergo reversible shape deformations on heating are formed.

A New General Synthetic Strategy for Phase-Pure Complex Functional Materials

The ability of ionic liquids to solvate inorganic salts completely has to date never been employed in the synthesis of complex inorganic materials. Here, we demonstrate that complex functional oxides, even those traditionally considered extremely difficult to synthesize in bulk, such as quinternary superconductors, are produced with no impurity phases and on timescales that are much shorter than other synthetic techniques.

Spontaneous Thermoreversible Formation of Cationic Vesicles in a Protic Ionic Liquid

The search for stable vesicular structures is a long-standing topic of research because of the usefulness of these structures and the scarcity of surfactant systems that spontaneously form vesicles in true thermodynamic equilibrium. We report the first experimental evidence of spontaneous formation of vesicles for a pure cationic double tail surfactant (didodecyldimethylammonium bromide, DDAB) in a protic ionic liquid (ethylammonium nitrate, EAN). Using small and ultra-small angle neutron scattering, rheology and bright field microscopy, we identify the coexistence of two vesicle containing phases in compositions ranging from 2 to 68 wt %. A low density highly viscous solution containing giant vesicles (D 30 μm) and a sponge (L3) phase coexists with a dilute high density phase containing large vesicles (D 2.5 μm). Vesicles form spontaneously via different thermodynamic routes, with the same size distribution, which strongly supports that they exist in a true thermodynamic equilibrium. The formation of equilibrium vesicles and the L3 phase is facilitated by ion exchange between the cationic surfactant and the ionic liquid, as well as the strength of the solvophobic effect in the protic ionic liquid.