8 results match your criteria: "University of Sheffield Dainton Building[Affiliation]"

The inductive effect is a central concept in chemistry and is often exemplified by the p values of acetic acid derivatives. The reduction in p is canonically attributed to the reduction in the electron density of the carboxylate group through the inductive effect. However, wave functional theory calculations presented herein reveal that the charge density of the carboxylate group is not explained by the inductive effect.

View Article and Find Full Text PDF
Article Synopsis
  • Polymerization-induced self-assembly (PISA) is an effective method for creating self-assembled AB diblock copolymer nano-objects in water, which can be further modified through chain extension with various monomers.
  • The study explores how using poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methacrylate) vesicles as seeds leads to the formation of different structures (like worms or spheres) depending on the type of polymerization and concentration.
  • This research demonstrates that incorporating a specific block (POEGMA) into the copolymer can enhance thermoresponsive properties in the resulting ABC triblock nano-objects, offering new opportunities for designing materials with customizable features.
View Article and Find Full Text PDF

This study is focused on the formation of polymer/silica nanocomposite particles prepared by the surfactant-free aqueous emulsion polymerization of 2,2,2-trifluoroethyl methacrylate (TFEMA) in the presence of 19 nm glycerol-functionalized aqueous silica nanoparticles using a cationic azo initiator at 60 °C. The TFEMA polymerization kinetics are monitored using H NMR spectroscopy, while postmortem TEM analysis confirms that the final nanocomposite particles possess a well-defined core-shell morphology. Time-resolved small-angle X-ray scattering (SAXS) is used in conjunction with a stirrable reaction cell to monitor the evolution of the nanocomposite particle diameter, mean silica shell thickness, mean number of silica nanoparticles within the shell, silica aggregation efficiency and packing density during the TFEMA polymerization.

View Article and Find Full Text PDF

Polymerization-induced self-assembly (PISA) is exploited to design hydrogen-bonded poly(stearyl methacrylate)-poly(benzyl methacrylate) [PSMA-PBzMA] worm gels in -dodecane. Using a carboxylic acid-based RAFT agent facilitates hydrogen bonding between neighboring worms to produce much stronger physical gels than those prepared using the analogous methyl ester-based RAFT agent. Moreover, tuning the proportion of these two types of end-groups on the PSMA chains enables the storage modulus (') of a 20% w/w worm gel to be tuned from ∼4.

View Article and Find Full Text PDF

It is well-known that treatment of β-octaethylporphyrin with H O /conc. H SO converts it to a β-oxochlorin as well as all five constitutional isomers of the corresponding β,β'-dioxo-derivatives: two bacteriochlorin-type isomers (β-oxo groups at opposite pyrrolic building blocks) and three isobacteriochlorin-type isomers (β-oxo-groups at adjacent pyrrolic building blocks). By virtue of the presence of the strongly electronically coupled β-oxo auxochromes, none of the chromophores are archetypical chlorins, bacteriochlorins, or isobacteriochlorins.

View Article and Find Full Text PDF

Dilute dispersions of poly(lauryl methacrylate)-poly(benzyl methacrylate) (PLMA-PBzMA) diblock copolymer spheres (a.k.a.

View Article and Find Full Text PDF

It is well-known that pluripotent human embryonic stem cells (hPSC) can differentiate into any cell type. Recently, we reported that hPSC colonies enter stasis when immersed in an extremely soft hydrogel comprising hydroxyl-functional block copolymer worms (I. Canton, N.

View Article and Find Full Text PDF

Fallen leaves are the main issues for train operations in the autumn season due to their low friction coefficient (COF), leading to signals being passed dangerously and amended timetables. The main aim of this study was to elucidate the mechanism of low friction due to black leaf films, which are often seen on leaf-contaminated rails. A black material was successfully synthesised in the laboratory with water extracts from sycamore leaves and a plate of R260 rail steel.

View Article and Find Full Text PDF