c******x
发帖数: 438 | 1 I have an unknown polymer solution ( at least in visible light), the solvent
is deionzied water. can I use DLS (?any kind of DLS or specified DLS) to
measure molecular weight/distribution, or the particle size/distribution. If
OK, how I can do? I don't know the initial concentration, but I can figure
out to measture the solid content in the solution after freeze drying.
Thanks in advance for any suggestion. | c********r
发帖数: 154 | 2 DLS can measure particle size in water of course. But there is an appropriat
e size range. If the size is below several nm or above several micrometer (n
ot sure the exact range), it does not work. And be aware of the measured siz
e. It is the so-called hydrodynamic size. By the way, static light scatterin
g may be better in some way. Good luck!
solvent
If
figure
【在 c******x 的大作中提到】
: I have an unknown polymer solution ( at least in visible light), the solvent
: is deionzied water. can I use DLS (?any kind of DLS or specified DLS) to
: measure molecular weight/distribution, or the particle size/distribution. If
: OK, how I can do? I don't know the initial concentration, but I can figure
: out to measture the solid content in the solution after freeze drying.
: Thanks in advance for any suggestion.
| k*******a
发帖数: 772 | 3 i think
DLS is for size measurement
SLS is for molecular weight measurement
solvent
If
figure
【在 c******x 的大作中提到】
: I have an unknown polymer solution ( at least in visible light), the solvent
: is deionzied water. can I use DLS (?any kind of DLS or specified DLS) to
: measure molecular weight/distribution, or the particle size/distribution. If
: OK, how I can do? I don't know the initial concentration, but I can figure
: out to measture the solid content in the solution after freeze drying.
: Thanks in advance for any suggestion.
| c******x
发帖数: 438 | 4 Many thanks. Actually i later talked to a technician about DLS, he said DLS
is better for monodisperse particle or within very short range. For
polydispersity, he said the data may not be trusted, also dust/containmation
can casue a lot of trouble.I only want to find a short-cut, if no other
choice, may play with zimm-plot.Thanks again. | t***u
发帖数: 20182 | 5 ?
DLS
containmation
【在 c******x 的大作中提到】
: Many thanks. Actually i later talked to a technician about DLS, he said DLS
: is better for monodisperse particle or within very short range. For
: polydispersity, he said the data may not be trusted, also dust/containmation
: can casue a lot of trouble.I only want to find a short-cut, if no other
: choice, may play with zimm-plot.Thanks again.
| m*********s
发帖数: 1188 | 6 you can DLS for sure to see the size. It give hydrodynamic size but for
polymer materials DLS has a well-established method for MW estimation (
should be an included option in your DLS machine). Also, it can give you the
size distribution/MW distribution.
But, be sue you got a good correlation curve for measurement.
I suspect about the opinion of your DLS technician. Because DLS can measure
polydispersity of particles in solution, while SLS can not do it. It's true
that monodisperse solution wil | c******x
发帖数: 438 | 7 If no standard, as I mentioned it is unknown polymer, I still can run GPC? I
already ran the DLS, it gave me good correlation curve. The DLS I used is
for size/zeta-potential measurement, so I only got the data of size and
distribution. I couldn't find the option for MW measurement,maybe I need to
ask somebody again. Thanks for your help.
the
measure
true
【在 m*********s 的大作中提到】
: you can DLS for sure to see the size. It give hydrodynamic size but for
: polymer materials DLS has a well-established method for MW estimation (
: should be an included option in your DLS machine). Also, it can give you the
: size distribution/MW distribution.
: But, be sue you got a good correlation curve for measurement.
: I suspect about the opinion of your DLS technician. Because DLS can measure
: polydispersity of particles in solution, while SLS can not do it. It's true
: that monodisperse solution wil
| m*********s
发帖数: 1188 | 8 You mean you don't have GPC standards or your polymer is not standard? GPC
is used to measure the MW and polydispersity of polymers, right?
As you are using zetasizer, check the data view options on your machine.At
least Malvern's zetasizer can give MWw for polymers.It may give your
estimated values.If you want accurate number, then your need to use
standards like polystyrene and the better you know about the confirguration
of your polymers (globule, rod, line ?) and some other parameters as wel
【在 c******x 的大作中提到】
: If no standard, as I mentioned it is unknown polymer, I still can run GPC? I
: already ran the DLS, it gave me good correlation curve. The DLS I used is
: for size/zeta-potential measurement, so I only got the data of size and
: distribution. I couldn't find the option for MW measurement,maybe I need to
: ask somebody again. Thanks for your help.
:
: the
: measure
: true
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