We describe here a method to synthesize ultrasmall nanocapsules with a diameter of 6 nm, exhibiting a well-defined core-shell morphology. Remarkably, the nanocapules are synthesized in a miniemulsion process without the need of large amounts of surfactant as commonly used in the microemulsion process. Ultrasmall nanocapsules with an oil core and a silica shell are formed by the concurrent processes of a sol-gel reaction and Ostwald ripening. Using solvents with different water solubilities and alkoxysilanes with different reactivities, we demonstrate that sizes of obtained nanocapsules depend on the ripening rate and alkoxysilane conversion rate. The method can be also used for encapsulating natural oils such as peppermint oil and limonene. This work shows that the Ostwald ripening phenomenon can be employed beneficially for the preparation of very small colloids.
https://ift.tt/2SGm8oj
I’m slaking quicklime to lime putty. Lime putty undergoes Ostwald ripening with age. Is it possible to accelerate this. If so, how would I go about it?
For supported nanoclusters at typical catalytic temperatures, Ostwald ripening is strongly accelerated by structural fluxionality, even in the regime of cluster size‐selection. Hence, a revision of the theory of Ostwald ripening is proposed.
Abstract
Size selection was demonstrated to suppress Ostwald ripening of supported catalytic nanoparticles. When the supported clusters are subnanometer in size and highly fluxional, such as Pt clusters on the rutile TiO2(110) surface, this paradigm breaks down, and the established theory of sintering needs a revision. At temperatures characteristic of catalysis (i.e. 700 K), sub‐nano clusters thermally populate many low‐energy metastable isomers. As these isomers all have different geometric and electronic structures, and thus, formation and dissociation energies (in lieu of surface energy), Ostwald ripening is not suppressed, despite the size‐selection. However, some clusters arise as magic numbers in terms of sintering stability at the ensemble level. Acceleration of sintering by metastable species persists though weakens in polydisperse cluster systems. We propose a competing pathways theory for sintering, which at the atomistic level describes the found size‐specific sintering behavior.
https://ift.tt/3dMQuO2
Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c10674
Soohyun Park, Tun Naw Sut, Gamaliel Junren Ma, Atul N. Parikh, and Nam-Joon Cho
https://ift.tt/3riX6bq
Hello everyone,
I was looking for some answers concerning the Oswalsd’s viscometer and I haven’t been able to find them in google. These are my questions: What kind of liquids can I use with the oswald’s viscometer? I know that it need to be Newtonian liquids but specifically I’m not quite sure, which lead us to my next question. Are transparent, foaming and liquids with high volatile components the only liquids that we can use? And if so, why?
Thank you and sorry for my level of English, it isn't my first language.
Hi,
I'd like to measure viscosity of some creams for an experiment using an Ostwald's Viscometer (The glass ones)..
How is this done? there's no clear explanation
Trying to read about Ostwald, especially his theory of energetics and his relation to the positivism of Mach.
My German is not good enough for source material really, so hoping there’s some good secondary literature. Anyone heard of any?
Also any good books on the history of positivism more generally would be very much appreciated! Thanks
As I was walking up the steps I accidentally tapped light attack rather than initiate conversation and nicked him for a tiny amount of damage. I thought if I let him kill me he would chill out but no. If it was anyone else I would just run to Ostwald and confess my sins, but he seems to be intent on stabbing me in the face.
Everything online just gives tips on how to kill him, so I figured I might as well ask here
"The Origins and Development of Kanō Jigorō’s Jūdō Philosophies"
By Lance Gatling, from pg 50.
International Judo Federation, The Arts and Science of Judo, 2nd Edition.
https://www.ijf.org/news/show/the-arts-and-sciences-of-judo-second-edition
I don't want to step on anybody's toes here, but the amount of non-dad jokes here in this subreddit really annoys me. First of all, dad jokes CAN be NSFW, it clearly says so in the sub rules. Secondly, it doesn't automatically make it a dad joke if it's from a conversation between you and your child. Most importantly, the jokes that your CHILDREN tell YOU are not dad jokes. The point of a dad joke is that it's so cheesy only a dad who's trying to be funny would make such a joke. That's it. They are stupid plays on words, lame puns and so on. There has to be a clever pun or wordplay for it to be considered a dad joke.
Again, to all the fellow dads, I apologise if I'm sounding too harsh. But I just needed to get it off my chest.
