Synthesis of Fluorinated Homopolymers by ATRP and the Determination of Their Extent Solubility in CO2 by Light Scattering

1
Synthesis of Fluorinated Homopolymers by ATRP
andthe Determination of Their Extent Solubility
in CO2 by Light Scattering
Tiffani Nicole Baileyi sarah l. folkii, joseph
m. desimoneii,iii
I.Hampton University School of Science Hampton,
VA 23668 II.University of North Carolina at
Chapel Hill Dept of Chemistry, Venable Hall CB
3290 Chapel Hill, NC 27599 III. North Carolina
State University Dept of Chemical
Engineering Raleigh, NC 27695 NSF Science and
Technology Center for Environmentally Responsible
Solvents and Processes
2
Objective

• To determine the relative solubilities of
• a collection of fluorinated Methacrylates
• and Acrylates in CO2 as a function of
• molecular weight and structure.

3
Atom Transfer Radical Polymerization
A CLASSICAL ATRP REACTION SCHEME
4
Polymerization of MMA
5
PMMA GPC results
Sample Mn (gpc) Mn (converted from PS) PDI
Bulk 40,000 754,000 51,500 980,000 1.30 1.41
Diphenyl Ether (50 v/v monomer) 37,400 48,200 1.29
Toluene (50 v/v monomer) 34,400 44,300 1.29
Toluene (33 v/v monomer) 29,400 37,800 1.29
Mn, targeted 22,000g/mol
GPC of PMMA synthesized in toluene (33 v/v
monomer) Eluent THF
6
Polymerization of FOMA
7
PFOMA Monitoring of Conversion
monomer
monomer
polymer
polymer
polymer
monomer
7 6 5 4 3 2
1 0
7 6 5 4 3 2
1 0
7 6 5 4 3 2
1 0
4hr 5min 74.2
1hr 15min 12.8
22hr 30min 93.3
8
PFOMA Molecular Weight Determination
Sample Mn, targeted Mn, NMR
PFOMA 20,000 12,100
PFOMA 50,000 55,000
9
Cloud Point Curve of PFOMA
one phase
two phase
1.2 w/w in CO2
10
Light Scattering

• Conventional solvents
• isorefractive
• too little contrast

• In CO2 we can determine
• Molecular Weight
• Size
• A2 (second virial coefficient)

Comparison of fluorinated homopolymer
solubilities by A2
11
Future Works
25 Branching of Fluorinated Chains
25 Branching of Fluorinated Chains
Perfectly Linear
Perfectly Linear
12
Acknowledgments

• North Carolina at Chapel Hill SPGRE Program/
• National Science Foundation
• Dr. Mireille Adam, Dr. Darlene Taylor,
• Dr. Jason Keiper, and Karen Erford
• This material is based upon work supported in
  part
• by the STC Program of the National Science
• Foundation under Agreement No. CHE-9876674.