Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Bis(indolyl)-coordinated titanium dichlorido complexes were applied for ethylene polymerization. The results showed that [{bis(indolyl)}TiCl2]2 activated by modified methyl aluminoxane (MMAO) exhibited ethylene polymerization activity up to 2494 (kg of polyethylene)/(mol of Ti)·h·atm. This activity is comparable to the highest known activity in catalyst systems based on diamido-supported titanium complexes. The [{bis(indolyl)}TiCl2]2/MMAO catalyst system was also active for propylene polymerization (344 (kg of polypropylene)/(mol of Ti)·h·atm) to furnish atactic polypropylene.
Natural rubber is a biopolymer with unique features widely used in many industrial applications. It is composed mainly by large high-molecular-weight polymeric chains of cis-1,4-polyisoprene with distinct α-terminal groups, which are thought to give natural rubber its specific features. The second most abundant molecule in natural rubber is L-quebrachitol, a cyclic polyol which function is not clear. Here we studied using atomistic simulations the interaction of L-quebrachitol with the hydrophobic natural rubber and its interaction with specific α-terminal groups, suggesting it binds preferentially with specific α-terminal groups.
Disiloxane-linked decathiophene and dodecathiophene polymers were prepared and their optical properties were examined. Compared with the monosilane-linked congeners reported previously, these polymers showed slightly redshifted absorption and PL bands in solution. Interestingly, the PL bands were redshifted when the spectra were measured in film, and the redshifts became pronounced as the silicon linkers were elongated from monosilane to disiloxane. This is likely due to the enhanced aggregation of the oligothiophene units, reflecting the improved flexibility of the silicon linkers.
Time-resolved small-angle X-ray scattering measurements were made for a mixed solution of silica nanoparticles (SiNPs) and atelocollagen (AC) in aqueous media. The scattering intensity from the SiNPs gradually changed and reached asymptotic values approximately 5–20 min after rapid mixing of the two solutions. The obtained time scale to form the complex can be important information to control the aggregating structure of SiNPs with the aid of collagen molecules.
We developed lanoconazole (LCZ)-loaded emulsions stabilized with cellulose nanocrystals grafted with polyphosphoesters (LCZ-loaded CP-PEs). The sustained release of LCZ and superior skin permeation of the LCZ-loaded CP-PEs, likely due to the excellent stability and rigidity of oil droplets, assured prolonged local action. The anti-inflammatory efficacy of the LCZ-loaded CP-PEs was confirmed using a mouse ear model of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation.
We prepared monolayer- and bilayer-type AuNP-containing collagen coatings as a photosensitive cell scaffold in a photoinduced in situ cell detachment system. The monolayer type of AuNP/collagen coatings showed efficient cell detachment with cell damage and may be applied to remove undesired cells. The bilayer-type AuNP/collagen coatings may be applied to collect desired cells because of the low cell damage. We demonstrated the sorting of visually changed transfected CHO-K1 cells and human-induced pluripotent stem cell-derived cardiomyocytes using our system, which is useful for genome editing and regenerative medicine, respectively.
We demonstrate the facile tuning of uniform Bragg reflection color from red to blue by uniaxial compression of gel films containing single-crystalline loosely packed colloidal crystals. The tuned colors can be fixed by photopolymerization of a polymer precursor solution contained in the compressed gel films.
Over the past two decades, intensive efforts have been devoted to the development of group-10 metal catalysts, especially nickel and palladium ligated by unsymmetric bidentate ligands aimed at the copolymerization of olefins with polar monomers. Here we synthesized a palladium complex bearing a methoxyethoxygroup and applied it to the copolymerization of ethylene and methyl acrylate. Higher incorporation of methyl acrylate was detected in the presence of lithium borate such as LiBArF4. The effect was limited to lithium, and the counteranion also affected the catalyst performance.
In this Note, the heat-proofing and anti-plasticizing nature of poly(ethylene carbonate) by the addition of a defibered plant (DP) is presented. The DP was obtained via simple wet-milling treatment for water-dispersed Japanese cedar. The presented results encourage us to use plants as functional fillers without a special chemical/biological reaction.
Catalytic ester-interchange reactions allow new sequence information to be written statistically into poly(ester-imide) chains based on NDI (1,4,5,8-naphthalenetetracarboxylic diimide) units. Insertion of the cyclic ester cyclopentadecanolide (“exaltolide”) into an NDI-based homopolymer and quantitative sequence exchange between two different homopoly(ester-imide)s are both catalyzed by di-n-butyl tin(IV) oxide. Emerging sequences from these reactions are identified using pyrene-d10 as a “reader molecule” that binds rapidly and reversibly to the NDI residues, and amplifies the separation of 1H NMR resonances associated with different sequences via cumulative aromatic ring-current shielding.
A dinuclear Pd(II) complex possessing a cyclic ligand was applied as a coordinative cross-linker of acrylonitrile–butadiene rubber (NBR). Tensile tests revealed that the mechanical properties of the coordinatively cross-linked NBRs were improved compared with those of the original NBR. Increasing the loading amount of the complex enhanced Young’s modulus, tensile strength, tensile strain, and toughness. The cross-linked NBR could be reused with a simple dissolution and drying process, which featured coordinative cross-linking.
We report a novel approach of siloxane bond splitting in organosiloxane using mixture of tris(pentafluorophenyl)borane and dimethyl carbonate. In the first part of this note, depolymerization of polydimethylsiloxane by dimethyl carbonate and with the addition of tris(pentafluorophenyl)borane is studied. Reactions are studied at different concentrations of above-mentioned reagents and temperature while the second part of this note represents theoretical calculation results which explain the mechanism of the depolymerization reaction.
