glueshooter
Harmless
Posts: 17
Registered: 4-9-2008
Location: PA
Member Is Offline
Mood: Spectacular
|
|
Hydrogen bonding preference
I hope that's not a horrible subject line. I have a question about how hydrogen bonds form, and how to estimate which chemical in a solution is more
likely to create the bond, if more than one fluid can do it. I won't be cagey, I'll just ask.
I'm making a solution of water, 1-propanol, and PVP. I'm not going to get into the whys of these being the components, they simply are. Here's my
question.
Both the water and the alcohol can dissolve the PVP, though I would suspect that water is better at it. Here's the thing. I need to get enough alcohol
into the fluid to get a surface tension that's as constant as possible over a dynamic to static range. So that means that I need so much 1P per unit
water, but I also need to account somehow for the waters that bond with PVP, and the alcohol that bonds with the PVP. I think, and I guess this is
something I also don't know, when the alcohol gets trapped by the PVP, it's not 'available' to reduce the surface tension. Am I crazy?
Can anyone tell me how I could go about figuring out what I need to do without making a million fluids?
Thanks, D.
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Hi,
Polyvinylpyrrolidone? (it helps to specify before abbreviating, we're not mind readers).
Dynamic to static range of what? Mechanical (vibration to no vibrations)?
|
|
|
glueshooter
Harmless
Posts: 17
Registered: 4-9-2008
Location: PA
Member Is Offline
Mood: Spectacular
|
|
Hi Blogfast25, yes, polyvinylpyrrolidone. You can read minds! But anyway, dynamic to static surface tension. When you're using surfactants, you see a
range of ST values depending on whether the fluid is sitting still or moving. Water, as I'm sure you know, has a very high ST, while alcohol is very
low. So I use 1-Propanol to enhance the wetting.
What I'm really trying to figure out is how to account for alcohol that 'binds' to the PVP. Bind probably isn't the right word, and I may be wrong to
even think about it. But OK, according to the PVP maker, solution requires about 1/2 mole of water for each chain unit of PVP. I'm inferring that in
the case of 1-Propanol, you probably need more of a 1:1 ratio since it only has one hydrogen site. Oh, and I'm assuming that all of these are hydrogen
bonds. But I'm not a chemist, so I really don't know. The biggest part of the problem, really.
So, if an alcohol creates an H-bond with PVP, is it still available to knock down surface tension? Is there going to be some type of normal
equilibrium between H-bonds from water and H-bonds from 1-Propanol? Is it something that cen be predicted?
Thanks again, D.
|
|
|
gatosgr
Hazard to Others
Posts: 237
Registered: 7-4-2015
Member Is Offline
Mood: No Mood
|
|
https://en.wikipedia.org/wiki/Hansen_solubility_parameter
|
|
|
smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
Member Is Offline
Mood: hmm...
|
|
This paper might get you on the right track -
Surface tension of non-ideal binary and ternary liquid mixtures at various temperatures and p = 81.5 kPa
A.A. Rafati. The Journal of Chemical Thermodynamics. Volume 43, Issue 3, March 2011, Pages 248–254.
http://www.sciencedirect.com/science/article/pii/S0021961410...
You're thinking about the problem correctly, unfortunately I think you need to apply some statistical mechanics. If you really want a good theoretical
calculation to steer you the right way get ready to read some literature and do the math. No one here is going to do that for you. Best wishes
|
|
|
gatosgr
Hazard to Others
Posts: 237
Registered: 7-4-2015
Member Is Offline
Mood: No Mood
|
|
HERE
http://orbit.dtu.dk/fedora/objects/orbit:13360/datastreams/f...
|
|
|
glueshooter
Harmless
Posts: 17
Registered: 4-9-2008
Location: PA
Member Is Offline
Mood: Spectacular
|
|
Thanks guys so much! Totally on the right track! And check this out!
http://hansen-solubility.com/SolventBlends.html
I would have never known to look for this. Thanks!
[Edited on 1-7-2015 by glueshooter]
|
|
|
smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
Member Is Offline
Mood: hmm...
|
|
Very cool web-site. Let us know if you find anything else 
|
|
|
glueshooter
Harmless
Posts: 17
Registered: 4-9-2008
Location: PA
Member Is Offline
Mood: Spectacular
|
|
http://pirika.com/ENG/HSP/E-Book/index.html
Another loaded site. Now I just have to figure out how to apply it properly.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
