An emulsion was stabilized by silica particles in combination with a charge‐reversible surfactant, which can be converted between anionic, zwitterionic and cationic forms by pH trigger. Not only can rapid demulsification be achieved, but the emulsion can also be reversibly switched between an oil‐in‐dispersion emulsion and a Pickering emulsion. This strategy endows the emulsion with the capacity for intelligent and precise control of stability as well as viscosity and droplet size.
Abstract
A novel charge‐reversible surfactant, (CH3)2N‐(CH2)10COONa, was designed and synthesized, which together with silica nanoparticles can stabilize a smart n‐octane‐in‐water emulsion responsive to pH. At high pH (9.3) the surfactant is anionic carboxylate, which together with the negatively charged silica nanoparticles co‐stabilize flowable oil‐in‐dispersion emulsions, whereas at low pH (4.1) it is turned to cationic form by forming amine salt which can hydrophobize in situ the negatively charged silica nanoparticles to stabilize viscous oil‐in‐water (O/W) Pickering emulsions. At neutral pH (7.5), however, this surfactant is converted to zwitterionic form, which only weakly hydrophobises the silica particles to stabilize O/W Pickering emulsions of large droplet size. Moreover, demulsification can be achieved rapidly triggered by pH. With this strategy particles can be controlled either dispersed in water or adsorbed at the oil‐water interface endowing emulsions with the capacity for intelligent and precise control of stability as well as viscosity and droplet size.
https://ift.tt/3c0yn6e
The dehydration of n‐octanaloxime to n‐octanenitrile catalysed by an aldoxime dehydratase (OxdB) overexpressed in E. coli is carried out in Pickering emulsions stabilised solely with silica particles of different hydrophobicity. The effects of particle wettability and particle concentration are evaluated with respect to the conversion of the reaction.
Abstract
Pickering emulsion systems have emerged as platforms for the synthesis of organic molecules in biphasic biocatalysis. Herein, the catalytic performance was evaluated for biotransformation using whole cells exemplified for the dehydration of n‐octanaloxime to n‐octanenitrile catalysed by an aldoxime dehydratase (OxdB) overexpressed in E. coli. This study was carried out in Pickering emulsions stabilised solely with silica particles of different hydrophobicity. We correlate, for the first time, the properties of the emulsions with the conversion of the reaction, thus gaining an insight into the impact of the particle wettability and particle concentration. When comparing two emulsions of different type with similar stability and droplet diameter, the oil‐in‐water (o/w) system displayed a higher conversion than the water‐in‐oil (w/o) system, despite the conversion in both cases being higher than that in a “classic” two‐phase system. Furthermore, an increase in particle concentration prior to emulsification resulted in an increase of the interfacial area and hence a higher conversion.
https://ift.tt/32ewtK7
A light‐responsive Pickering emulsion was designed and prepared, which could be reversibly switched between stable and unstable upon exposure to visible and UV light, respectively. The reversible, light‐responsive phase behavior of the Pickering emulsion enabled its use as a microreactor, allowing highly efficient catalytic hydrogenation, followed by product separation and emulsifier and catalyst recycling.
Abstract
Pickering emulsions are an excellent platform for interfacial catalysis. However, developing simple and efficient strategies to achieve product separation and catalyst and emulsifier recovery is still a challenge. Herein, we report the reversible transition between emulsification and demulsification of a light‐responsive Pickering emulsion, triggered by alternating between UV and visible light irradiation. The Pickering emulsion is fabricated from Pd‐supported silica nanoparticles, azobenzene ionic liquid surfactant, n‐octane, and water. This phase behavior is attributed to the adsorption of azobenzene ionic liquid surfactant on the surface of the nanoparticles and the light‐responsive activity of ionic liquid surfactant. The Pickering emulsion can be used as a microreactor that enables catalytic reaction, product separation as well as emulsifier and catalyst recycling. Catalytic hydrogenation of unsaturated hydrocarbons at room temperature and atmospheric pressure has been performed in this system to demonstrate product separation and emulsifier and catalyst re‐use.
https://ift.tt/2I6H7uX
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.
Do your worst!
I'm surprised it hasn't decade.
For context I'm a Refuse Driver (Garbage man) & today I was on food waste. After I'd tipped I was checking the wagon for any defects when I spotted a lone pea balanced on the lifts.
I said "hey look, an escaPEA"
No one near me but it didn't half make me laugh for a good hour or so!
Edit: I can't believe how much this has blown up. Thank you everyone I've had a blast reading through the replies 😂
It really does, I swear!
Because she wanted to see the task manager.
They’re on standbi
Pilot on me!!
Nothing, he was gladiator.
Dad jokes are supposed to be jokes you can tell a kid and they will understand it and find it funny.
This sub is mostly just NSFW puns now.
If it needs a NSFW tag it's not a dad joke. There should just be a NSFW puns subreddit for that.
Edit* I'm not replying any longer and turning off notifications but to all those that say "no one cares", there sure are a lot of you arguing about it. Maybe I'm wrong but you people don't need to be rude about it. If you really don't care, don't comment.
When I got home, they were still there.
What did 0 say to 8 ?
" Nice Belt "
So What did 3 say to 8 ?
" Hey, you two stop making out "
I won't be doing that today!
[Removed]
Where ever you left it 🤷♀️🤭
This morning, my 4 year old daughter.
Daughter: I'm hungry
Me: nerves building, smile widening
Me: Hi hungry, I'm dad.
She had no idea what was going on but I finally did it.
Thank you all for listening.
There hasn't been a post all year!
You take away their little brooms
It was about a weak back.
It’s pronounced “Noel.”
After all his first name is No-vac
What, then, is Chinese rap?
Edit:
Notable mentions from the comments:
-
Spanish/Swedish/Swiss/Serbian hits
-
French/Finnish art
-
Country/Canadian rap
-
Chinese/Country/Canadian rock
-
Turkish/Tunisian/Taiwanese rap
There hasn't been a single post this year!
(Happy 2022 from New Zealand)
Nothing, it just waved
Him: I can explain everything!
(It's his best joke yet I think)
Bob
A novel charge‐reversible surfactant, (CH 3 ) 2 N‐(CH 2 ) 10 COONa, was designed and synthesized, which together with silica nanoparticles can stabilize a smart n ‐octane‐in‐water emulsion responsive to pH. At high pH (9.3) the surfactant is anionic carboxylate, which together with the negatively charged silica nanoparticles co‐stabilize flowable oil‐in‐dispersion emulsions, whereas at low pH (4.1) it is turned to cationic form by forming amine salt which can hydrophobize in situ the negatively charged silica nanoparticles to stabilize viscous oil‐in‐water (O/W) Pickering emulsions. At neutral pH (7.5), however, this surfactant is converted to zwitterionic form, which only weakly hydrophobises the silica particles to stabilize O/W Pickering emulsions of large droplet size. Moreover, demulsification can be achieved rapidly triggered by pH. With this strategy particles can be controlled either dispersed in water or adsorbed at the oil‐water interface endowing emulsions with the capacity for intelligent and precise control of stability as well as viscosity and droplet size.
https://ift.tt/3c0yn6e
Pickering emulsion systems have emerged as platforms for the synthesis of organic molecules in biphasic biocatalysis. Herein, the catalytic performance was evaluated for biotransformation using whole cells exemplified for the dehydration of n ‐octanaloxime to n ‐octanenitrile catalysed by an aldoxime dehydratase (OxdB) overexpressed in E. coli . This study was carried out in Pickering emulsions stabilised solely with silica particles of different hydrophobicity. We correlate, for the first time, the properties of the emulsions with the conversion of the reaction, thus gaining an insight into the impact of the particle wettability and particle concentration. When comparing two emulsions of different type with similar stability and droplet diameter, the oil‐in‐water (o/w) system displayed a higher conversion than the water‐in‐oil (w/o) system, despite the conversion in both cases being higher than that in a “classic” two‐phase system. Furthermore, an increase in particle concentration prior to emulsification resulted in an increase of the interfacial area and hence a higher conversion.
https://ift.tt/32ewtK7
Pickering emulsions have been shown to be an excellent platform for interfacial catalysis. However, developing simple and efficient strategies to achieve the goal of product separation and catalyst and emulsifier recovery is still a challenge. Herein, we report for the first time the switchable transition between emulsification and demulsification triggered by UV and visible light in a novel class of light‐responsive Pickering emulsions fabricated from Pd supported silica nanoparticles, azobenzene ionic liquid surfactant, n‐octane and water. It is shown that light‐switchable emulsification and demulsification of the Pickering emulsions is attributed to the adsorption of azobenzene ionic liquid surfactant on the surface of the nanoparticles and the light switched surface activity of the ionic liquid surfactant. This feature enables the Pickering emulsion to be used as an easily controlled micro‐reactor with the functions of catalytic reaction, product separation as well as emulsifier and catalyst recycling. As an example, highly efficient catalytic hydrogenation of some unsaturated hydrocarbons at room temperature and atmospheric pressure has been performed in this system, with product separation and emulsifier and catalyst re‐use achievable in a simple way.
https://ift.tt/2I6H7uX
