HSP Application note #59
Hansen Solubility Parameters (HSP) and Poly(vinylidene fluoride) swelling2010.11.13
HSPiP Team Senior Developer, Dr. Hiroshi Yamamoto
Poly(vinylidene fluoride) PVdF is used as binder resin for anode of Lithium Ion battery.
I found very interesting report written Japanese chemical company, Hitachi Chemical co..
Anode Binder Resin for Lithium Ion Batteries
http://www.hitachi-chem.co.jp/japanese/report/045/45_r1.pdf
They say, the swelling of binder resin disrupt conductive networks.
Let’s analyze this phenomena with Hansen Solubility Parameters (HSP).
Hansen Solubility Parameters (HSP)Hansen Solubility Parameters(HSP) were developed by Charles M. Hansen as a way of predicting if one material will dissolve in another and form a solution. They are based on the idea that "like dissolves like" where one molecule is defined as being 'like' another if it bonds to itself in a similar way.
What can perhaps be surprising is that one can assign HSP to so many different things. Gases like carbon dioxide, solids like carbon-60, sugar, and biological materials like human skin, depot fat, DNA, and even some proteins all have HSP. The list can be continued with drugs, polymers, plasticizers, and in fact any organic material and even many inorganic materials like salts. The only requirement for an experimental confirmation is that the material must behave differently in a sufficient number of test solvents upon contact. Pirika JAVA Demo Applet calculate HSP. HSPLight is available here. |
Binder Resin swelling -> Reduce Carbon black contact.
At first, I checked solubility of PVdF.
Solubility Parameters of Poly(vinylidene fluoride)
Journal of Polymer Science: Part B: Polymer Physics, Vol. 26,785-794(1988)
BOWINO, G. CAPANNELLI,*S. MUNARI, and A. TURTURRO
For 46 type of solvent, they list S: Good solvent, GSA: Good Swelling Agent, PSA: Partially Swelling Agent, NS: Not Solvent
And I appended several solvents information from Polymer HandBook.
| Name | dD | dP | dH | Score | Vol |
| acetaldehyde | 14.7 | 12.5 | 7.9 | 0 | 56.5 |
| acetic acid | 14.5 | 8 | 13.5 | 0 | 57.6 |
| acetone | 15.5 | 10.4 | 7 | 0 | 73.8 |
| acetonitrile | 15.3 | 18 | 6.1 | 0 | 52.9 |
| acetyl chloride | 16.2 | 11.2 | 5.8 | 0 | 71.3 |
| aniline | 20.1 | 5.8 | 11.2 | 0 | 91.6 |
| benzyl alcohol | 18.4 | 6.3 | 13.7 | 0 | 103.8 |
| butanol | 16 | 5.7 | 15.8 | 0 | 92 |
| butyl acetate | 15.8 | 3.7 | 6.3 | 0 | 132.6 |
| ethyl formate | 15.5 | 8.4 | 8.4 | 1 | 80.9 |
| hexamethyl phosphoramide | 18.5 | 11.6 | 8.7 | 1 | 175.7 |
| methyl acetate | 15.5 | 7.2 | 7.6 | 1 | 79.8 |
| methyl ethyl ketone | 16 | 9 | 5.1 | 1 | 90.2 |
| N-methyl-2-pyrrolidone | 18 | 12.3 | 7.2 | 1 | 96.6 |
| Propylene Carbonate | 20 | 18 | 4.1 | 1 | 85.2 |
| tetrahydrofuran | 16.8 | 5.7 | 5.7 | 1 | 81.9 |
| Tetramethylurea | 16.7 | 8.2 | 11 | 1 | 120.4 |
| triethyl phosphate | 16.7 | 11.4 | 9.2 | 1 | 170.8 |
| trimethyl phosphate | 15.7 | 10.5 | 10.2 | 1 | 116.6 |
I got 52 solvents data.
Score =1 (red square) are Good Solvents or Good Swelling Agents.
Score =0 (blue lozenge) are PSA or NS.
Plot these solvents in Hansen Space, all Good Solvents and Good Swelling Solvents are coming together and make Sphere.
Hansen SphereTo determine if the parameters of two molecules (usually a solvent and a polymer) are within range a value called interaction radius (R0) is given to the substance being dissolved. This value determines the radius of the sphere in Hansen space and its center is the three Hansen parameters.
From version 3.1.X, Double Spheres function is available. Pirika provide JAVA 3D Demo Applet to browse the Sphere(s). |
And the center of Sphere is determined as PVdF’s HSP.
This case dD=19.4, dP=15.9, dH=11.3 are PVdF’s HSP and write as [19.4, 15.9, 11.3].
And the radius of sphere is 9.6.
There are 7 exceptions. All of them are Wrong out (Distance from PVdF is long even though, they dissolve PVdF).
We need apply Double Spheres technique for this problem. See the end of this article.
As Electrolyte Solution, Ethylene Carbonate : DiEthyl Carbonate : DiMethyl Carbonate =1:1:1 is most popular.
HSP of Solvents mixture can calculate with this scheme.
HSP of Solvents Mixture[dDm, dPm, dHm]=[(a*dD1+b*dD2), (a*dP1+b*dP2),(a*dH1+b*dH2)]/(a+b)
Volume base ratio. Pirika Java demo applet design solvents mixture. GSD is available here. |
Solvent=EC:DEC:DMC=1:1:1->[16.2, 12.2, 6.1]
EC: Ethylene Carbonate [18, 21.7, 5.1]
DEC: DiEthyl Carbonate [15.1, 6.3, 3.5]
DMC: DiMethyl Carbonate [15.5, 8.6, 9.7]
So, Solvent[16.2, 12.2, 6.1] to Polymer[19.4, 15.9, 11.3] HSP distance become 9.04 (Sphere Radius 9.6), and this means PVdF will dissolve or Swell by this solvent.
In Hitachi Chemical report, they did not reveal co-monomer.
But they said, they tried to increase polarity of polymer. The PVdF polymer already have very large dP value. So, they might try to increase dH.
How can we increase polymer dH?
You can easily increase dH if you introduce Hydroxy group into polymer.
HSP of Poly(vinyl alcohol) PVA is [15.9,8.1,18.8] by estimation. Then we can calculate mixture HSP of PVdF [19.4, 15.9, 11.3] and PVA [15.9,8.1,18.8].
The distance from solvents should larger than 9.6, PVdF ratio should lower than 40%.
You can get above chart, if you use spreadsheet and make below table.
| PVdF | PVA | MixdD | MixdP | MixdH | DistfromSolvent |
| 0 | 100 | 15.9 | 8.1 | 18.8 | 13.36 |
| 1 | 99 | 15.935 | 8.178 | 18.725 | 13.26 |
| 2 | 98 | 15.97 | 8.256 | 18.65 | 13.16 |
| 3 | 97 | 16.005 | 8.334 | 18.575 | 13.07 |
| 4 | 96 | 16.04 | 8.412 | 18.5 | 12.97 |
| 5 | 95 | 16.075 | 8.49 | 18.425 | 12.87 |
| 6 | 94 | 16.11 | 8.568 | 18.35 | 12.78 |
| 95 | 5 | 19.225 | 15.51 | 11.675 | 8.87 |
| 96 | 4 | 19.26 | 15.588 | 11.6 | 8.90 |
| 97 | 3 | 19.295 | 15.666 | 11.525 | 8.93 |
| 98 | 2 | 19.33 | 15.744 | 11.45 | 8.96 |
| 99 | 1 | 19.365 | 15.822 | 11.375 | 9.00 |
| 100 | 0 | 19.4 | 15.9 | 11.3 | 9.04 |
Then how we can get such polymer?
In many case, PVA is made by hydrolysis of poly(vinyl acetate) PVac.
So vinylidene fluoride and vinyl acetate co-polymerization is one of the answer.
But introduction of each monomer is depend on monomer reactivity ratios.
If radical polymerization simulator is still working, please try.
Radical polymerization simulator.
vinylidene fluoride Q-Value 0.015, e-value 0.50
vinyl acetate Q-Value 0.026, e-Value 0.88
so, we get reactivity ratios by Alfrey and Price Qe Theory.
I made Monte Carlo (MC) simulator, and analyzed.
If you start VdF:Vac=40：60, in polymer will introduce 33.5 : 66.5
Monte Calro Simulation ver. 2008.12.17
A:Vdf
B:VAC
rij (Kii/kij)
1.0 0.697644
1.2406635 1.0
1% polymerization Image of Polymer
BAABBAABABBABBBBAABBBBBABBBABBBABBBABAABBABAAAAAB
BBBBBBBBABABBBBAABBBBBBBABBBBABBBBBAAABBAAABBBBBA
BBBAABABBBABBBBABBABBAABABBAAABABBABBBBBBABBABBAA
BBAABBBBABBABBBBBBBBBAABABBBBABBBBABABABBBBABABBB
BBBBBBABABBBBBABBBABBABAABBBBBBBBBABBBBBBAAAABBAB
BBBABBBABABBBBBBBABAAABBABBBBBABAABBBABAABAABBAAB
AABBBBBBBABBBBBBABABAAABBBBBABBBBBABBAABBABBABBBB
ABBABABAAABBBABBABABBAABBBABBBABBBBABBABBBBABBABA
BABBBBBBBBBABABBBBBBAAABABAABABBABABBABABABBABBBA
BBABBBBBBAAABBBABBABBABABBABBBBBBBABBABBBBAAABBBA
Monomer mol% ratio
A: 40.0
B: 59.9
In polymer
A: 33509 (33.5%)
B: 66492 (66.49%)
Diad
A-A: 10581 (10.58%)
A-B: 22927 (22.92%)
B-A: 22928 (22.92%)
B-B: 43564 (43.56%)
Initial mol ratio is set to VdF:Vac=46.7：53.2
BAAABAABABABABBABBABBBBBBAAABABABBABBAABBABBBABBB
ABBAAAABBABBBBBABBABAABAABBBAABAABBABBABBBBBABBAB
BAAABABBABBBABABBABABBBBABABBBBBABBBAAAABBBBAAABB
BBABBBABBABBAABAABABABABBBBBBBAAABABBBAAABAABAABA
BABBAABBAABBBBBBBBAAABABAABBBBABBABBAABBBABAABBBA
BBBBAAABBBBABBBBBBBBBABBBBBABBBBBAABBBAAAAABABBBA
BABBABBBBBABABABBBABBBABBBBBBAABAABABBBAABAAABBBB
BBBBABBBBBBBBBAABBBABABBBABABAABABBABBABAABBAABAA
BBBABBBBAAABBBABBBBABBBBBBAABBAABBAABABBBABBBBBBB
BBBBABABABAAAAABBBABABBBBAAABAABBBBBAAABBBBBABBAB
The ratio of introduced monomer become VdF:Vac=40:60
Then hydrolysis PVA part.
Maybe you would better reduce Vac ratio and make several polymer and find most suitable ratio in real work.
If you try to use Hydroxy ethyl Methacrylate(HEMA), you need care.
A:Vdf
B:HEMA
rij (Kii/kij)
1.0 0.007975998
123.86824 1.0
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBABBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBABBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
BBBBBBBBBABBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB
Monomer mol% ratio
A: 50.0
B: 50.0
In polymer
A: 804 (0.8%)
B: 99197 (99.19%)
Initial monomer ratio VdF:HEMA=50:50, 99％HEMA polymer will produce.
If we use HSPiP and Pirika simulator, we can design real materials.
HSPiP(Hansen Solubility Parameters in Practice)The first edition of HSPiP that appeared in November, 2008, greatly enhanced the usefulness of the Hansen solubility parameters (HSP). The HSP values of over 1200++ chemicals and 500 polymers are provided in convenient electronic format and have been revised and updated using the latest data sources in the second edition (March, 2009). A third edition of the HSPiP appeared in March, 2010. There are now 10,000 compounds in the HSP file which also includes data on density, melting point, boiling point, critical parameters, Antoine constants and much more. The user is able to carry out many different sorts of optimisations of solubility, evaporation, diffusion, adhesion, create their own datasets (automatically if required) and explore the huge range of applications for HSP in coatings, paints, nanoparticles, cosmetics, pharma, organic photovoltaics and much more. The 3rd Edition v3.1 was released on 12 December 2010. Current users can upgrade free (now v3.1.09) by downloading the latest .msi installer from http://hansen-solubility.com The 4th Edition v4.0.x was released on 2 Jan. 2013. The Current users can upgrade with free charge. 2013.1.28 The Visual How to manual of HSPiP. You can understand what HSPiP can do. |
I used usual one Sphere (with option GA), I got [19.4, 15.9, 11.3] and Green Sphere radius is 9.6. You can see 7 exceptions (Blue Sphere out of Green Sphere) left down to Green Sphere.
Drag=Rotate, Drag+Shift=Larger/Smaller, Drag+Alt or Command(Window key)=Translate.
If you are using HTML5 enable browser such as Chrome, Safari or FireFox (IE9 is out of support), you will see the Canvas. If you pick solvent, solvent name will appear.
Drag=Rotate, Drag+Shift=Larger/Smaller, Drag+Alt or Command(Window key)=Translate.
If you are using HTML5 enable browser such as Chrome, Safari or FireFox (IE9 is out of support), you will see the Canvas. If you pick solvent, solvent name will appear.
I used Double Spheres.
1st Large Green Sphere, [19.1, 15.6, 10.2] Radius 8.45
2nd Small Green Sphere, [17.5, 6.3, 9.0] Radius 4.63
The exceptions solvents reduce to 2.
And we can understand PVdF solubility phenomena more easily.
This Double Spheres algorithm will be implemented to HSPiP ver. 3.1.X
Why PVdF have double natures?
The VdF monomer (CH2=CF2) will polymerize like
-CH2-CF2-CH2-CF2-CH2-CF2- (maybe Large Green Sphere)
but PVdF case, it is said that about 10% of abnormal bonding exist.
-CH2-CF2-CF2-CH2-CH2-CF2- (maybe Small Green Sphere)
Preparation of PVdF-base membranes.
Electric Conducting Sulfur Containing Polymer for Solar Cell.
