Electronic Supplementary Material (ESI) for RSC Advances. This journal is The Royal Society of Chemistry 2015 Supporting Information Well-defined polyelectrolyte and its copolymers by reversible addition fragmentation chain transfer (RAFT) polymerization: Synthesis and applications Muhammad Mumtaz 1,2, Karim Aissou 1,2, Dimitrios Katsigiannopoulos 1,2, Cyril Brochon 1,2, Eric Cloutet 1,2 * and Georges Hadziioannou 1,2 * 1 Centre National de la Recherche Scientifique, Laboratoire de Chimie des Polymères rganiques, UMR 5629, IPB/ENSCBP, Allée Geoffroy Saint Hilaire, Bât B8, F-33615, Pessac Cedex, France 2 Université de Bordeaux, Laboratoire de Chimie des Polymères rganiques, UMR 5629, IPB/ENSCBP, Allée Geoffroy Saint Hilaire, Bât B8, F-33615, Pessac Cedex, France Corresponding authors:hadzii@enscbp.fr; cloutet@enscbp.fr 1
Experimental Section Materials: 4-styrenesulfonic acid, sodium salt (90%, Sigma Aldrich), oxalyl chloride (98%, Alfa-Aesar), trifluoromethylsulfonamide (97%, ABCR), Triethylamine (Sigma Aldrich), anhydrous Dimethylformamide (Sigma Aldrich) and methacrylic acid (99% Sigma Aldrich) were used as received. Acetonitrile was purchased from Alfa-Aesar and was distilled over CaH 2. 2,2'-azobisisobutyronitrile (AIBN) (99%, Sigma-Aldrich) was recrystallized twice with methanol and stored in refrigerator at 4 C. Carbon nanotubes (CNT) were kindly supplied by ARKEMA. 2-(Dodecylsulfanylthiocarbonylsulfanyl)-2-methylpropionic acid was prepared according to the literature. 1 4-styrenesulfonyl (trifluoromethylsulfonyl) imide potassium monomer was prepared according to literature data 2 Polymerization of 4-styrenesulfonyl (trifluoromethylsulfonyl) imide potassium salt (see scheme 1b): A sample of PSKTFSI-CTA (run 10, Table 1) was prepared as follow: A 20 ml Schlenk tube was flame dried and charged with STFSIK (2g, 5.66 mmol), 2- (Dodecylsulfanylthiocarbonylsulfanyl)-2-methylpropionic acid (CTA) (36.4 mg, 1 10-1 mmol) AIBN (3.28 mg, 2 10-2 mmol) and 4 ml of anhydrous DMF. The Schlenk tube was subjected to five freeze thaw cycles and placed in an oil bath previously maintained at 65 C. Polymerization reaction was quenched after appropriate time by freezing in liquid nitrogen. The polymer was washed by precipitating twice in ether. The polymer was dried at 60ºC under vacuum for ~24h in order to remove the remaining solvents. The formation of PSTFSIK-CTA was confirmed by 1 H NMR Preparation of poly{4-styrenesulfonyl(trifluoromethylsulfonyl) imide} lithium salt (PSLiTFSI). PSLiTFSI was prepared by ion exchange with already prepared PSKTFSI as described earlier in the literature 2 with slight change in purification method. PSKTFSI (run 10, Table 1) was added into 50 ml of ethanol and an excess of lithium perchlorate (LiCl 4 ) 2
was subsequently introduced. The solution was heated to 45 o C under stirring overnight. Potassium perchlorate white precipitates were filtered out and solvent was removed on rotary evaporator to give a light yellow solid. Remaining lithium perchlorate was removed by solubilization of the solid in methanol followed by precipitation in ether. The resulting polymer was dried under vacuum at 40 C. Synthesis of PS-macroRAFT agent (PS-CTA). A 20 ml schlenk tube was flame dried and charged with styrene (5g, 4.8 10-2 mol) and CTA (2.5 10-4 mol). The Schlenk tube was subjected to five freeze thaw cycles and placed in a preheated oil bath at 120 C. Polymerization reaction was quenched after 8 hours by freezing in liquid nitrogen. The unreacted monomer was removed by double precipitation in methanol. Then the polymer was dried at 40ºC under vacuum in order to remove the remaining solvents. The polymer was characterized by 1 H NMR and SEC. Synthesis of PMMA and PMAA homopolymers Samples of PMMA (M n = ~23000 g/mol, D= 1.2) and PMAA (M n = ~6000 g/mol, D = 1.05) homopolymers were prepared by controlled radical polymerization as mentioned above and were characterized by 1 H NMR and SEC). Synthesis of PSKTFSI-b-PMAA. In a typical experiment (run 1, Table 2), a 20 ml Schlenk tube was flame dried and charged with previously synthesized PSTFSIK-CTA (1g, 1.67 10-4 mol, M n = 6000g/mol), MAA (1g, 1.12 10-2 mol), AIBN (5.5 mg, 3.33 10-5 mol) and 4 ml of DMF. The Schlenk tube was subjected to five freeze-thaw cycles and placed in an oil bath previously maintained at 65 C. Reaction was continued at this temperature under stirring overnight and then stopped by freezing in liquid nitrogen. An aliquot was taken for characterization purpose. The polymer was purified by precipitation in THF. The copolymer was dried at 50 C in an oven under vacuum. 3
Synthesis of PSTFSIK-b-PMMA. In a typical experiment (run 3, Table 2), a 10 ml Schlenk tube was flame dried and charged with previously synthesized PSTFSIK-CTA (400 mg, 3.67 10-5 mol, M n = 10900g/mol), MMA (800 mg, 8.0 10-3 mol), AIBN (1.2 mg, 7.34 10-6 mol) and 2 ml of DMF. The Schlenk tube was subjected to five freeze-thaw cycles and placed in an oil bath previously maintained at 65 C. Reaction was continued at this temperature under stirring overnight and then stopped by freezing in liquid nitrogen. An aliquot was taken for characterization purpose. The polymer was purified by precipitation in ether. The copolymer was dried at 50 C in a oven under vacuum. Synthesis of PS-b-PSTFSIK. In a typical experiment (run 4, Table 2), a 20 ml Schlenk tube was flame dried and charged with previously synthesized PS-CTA (1g, 1.14 10-4 mol, M n = 8800g/mol), STFSIK (1g, 2.83 10-3 mol), AIBN (4.0 mg, 2.44 10-5 mol) and 4 ml of DMF. The Schlenk tube was subjected to five freeze-thaw cycles and placed in an oil bath previously maintained at 65 C. Reaction was continued at this temperature under stirring for 24h and then stopped by freezing in liquid nitrogen. An aliquot was taken for characterization purpose. The polymer was purified by precipitation in ether. The copolymer was dried at 50 C in an oven under vacuum. Characterization: Proton Nuclear Magnetic Resonance ( 1 HMR) spectra were recorded on a Bruker AC-400 (400 MHz) spectrometer in appropriate deuterated solvents. Size exclusion chromatography (SEC) in DMF was used for the characterization of the molecular characteristics of the polymers. The characterization was performed on a PL-50 SEC system with TSK gel TSH (G4000, G3000, G2000 with pore sizes of 20, 75 and 200 Å respectively, connected in series) columns calibrated with polystyrene (PS) standards with DMF as eluent (0.8 ml/min) and toluene as a flow marker at 80 C, in the presence of LiBr (1 g/l) using both refractive index and UV detectors (Varian). For the higher molecular weights 4
was used the same system and conditions but with different columns (one Shodex Asahipak GF-1G 7B column guard and 2 columns Shodex Asahipak GF-7M HQ) and flow rate (0.6 ml/min, calibration standards PS 1-2000 kg/mol). Differential scanning calorimeter (DSC) thermograms were measured using a DSC Q100 apparatus from TA instrument. Tg was calculated from the second heating run. All the runs were performed at the rate of 10 C/min under nitrogen atmosphere. The thermogravimetric analysis (TGA) was performed on a TGA-Q500 system from TA instrument at the heating rate of 3-5 C/min under air. Synthesis of 4-styrenesulfonyl(trifluoromethylsulfonyl) imide potassium salt (Scheme 1a). 4-styrenesulfonyl(trifluoromethylsulfonyl) imide potassium salt was prepared according to reported procedure without using 4-dimethylaminopyrridine (DMAP) as a catalyst 14. xalyl chloride (3g, 23.6 mmol) and DMF (0.087g, 1mmol) were added in 40mL of dry acetonitrile and stirred for five hours to promote the formation of the Vilsmeier Haack complex. When the solution turned yellow, 4-styrenesulfonic acid sodium salt (4.30g, 20.8mmol) was added slowly to the solution under nitrogen atmosphere and at room temperature. This mixture was stirred for 15h. NaCl precipitates were separated by filtration. In another round bottom flask, triethylamine (8.7mL, 62.4mmol) and 2.89g of trifluoromethylsulfonamide (20.8mmol) were added in 40mL of dry acetonitrile under stirring in nitrogen atmosphere. The 4-styrene sulfonyl chloride solution was cooled to 0 C using ice bath and then the mixture of trifluoromethylsulfonamide was added slowly to this solution and placed under stirring for16h. Triethylammonium chloride produced was removed by filtration. The solvent from filtrate was removed by rotary evaporator and the resulting brown solid was dissolved in 50 ml of dichloromethane. This solution was washed twice with 20mL of an aqueous solution of NaHC 3 (4%) and 20mL of hydrochloric acid (1M). After 5
removing the solvents using rotary evaporator and vacuum drying gave a viscous brownish liquid which was identified as 4-styrenesulfonyl(trifluoromethylsulfonyl) imide triethylammonium salt (STFSI-TEA. The structure of STFSI-TEA salt was confirmed by 1 H NMR and 19 F NMR spectra (supporting information S2a) The potassium form of 4-styrenesulfonyl (trifluoromethylsulfonyl) imide was obtained by treating the monomer with a molar excess of K 2 C 3 in water. The resulting suspension was stirred for one hour, filtered and dried to give of a light yellow solid. Recrystallization from water gave white powder (55% yield). The formation of STFSIK was confirmed by 1 H NMR, 19 F NMR and 13 C NMR spectra 6
ESI 1a a H c H b H d e d' e' e,e d,d g DMS h S N S g h f H N c b a H 2 CF 3 f Fig. S1a: I H NMR of (4-styrenesulfonyl(trifluoromethylsulfonyl) imide triethylammonium salt 7
ESI 1b a H c H b H e,e d,d d d' e e' DMS S b a N S K H 2 CF 3 c Fig. S1b: I H NMR of 4-styrenesulfonyl(trifluoromethylsulfonyl) imide potassium salt ESI 2 Fig. S2: I9 F NMR of 4-styrenesulfonyl(trifluoromethylsulfonyl) imide potassium salt 8
ESI 3 d,d,e,e d a b c d' DMS b e f S N S e' K f c a CF g 3 g g g g Fig. S3: 13 C NMR of 4-styrenesulfonyl(trifluoromethylsulfonyl) imide potassium salt (SKTFSI) in d 6 -DMS. 9
ESI 4 Fig. S4: TGA traces of PSKTFSI, and PSLiTFSI (after ion exchange with PSKTFSI), samples. 10
ESI 5 Fig. S5: TGA Traces of PSLiTFSI homopolymer under air and nitrogen atmosphere (heating rate = 5 C/min) 11
ESI 6 Fig. S6: DSC traces for PSKTFSI samples with different molar masses at heating rate of 10 C/min under nitrogen atmosphere. 12
ESI 7 a b e f c c' CHCl 3 d d' CH 3 g g S g DMS N K DMS CDCl 3 d,d S CF 3 c,c H 2 H 2 a,b,e,f a,b,e,f d,d c,c Fig. S7: 1 H NMR of PSKTFSI-b-PMMA in DMS-d 6 /CDCl 3 mixture (run 3, Table 2) at RT. 13
ESI 8 b a RI response 669 769 869 969 1069 1169 Elution Time(Sec) Fig. S8: SEC traces of (a) PSKTFSI (run 7, Table 1) and (b) PSKTFSI-b-PMMA using DMF as an eluent at 60 C (run 3, Table 2) 14
ESI 9 Fig. S9: TGA traces of PSKTFSI-b-PMAA (run 1, Table 2), PSKTFSI-b-PMMA (run 3, Table 2) and PS-b-PSKTFSI (run 1, Table 3) in air at heating rate of 5 C/min] 15
ESI 10 Fig. S10: TGA traces of PMAA, PMMA and PS homopolymers under air at heating rate of 5 C/min 16
ESI 11 Fig. S11: DSC traces of PS-b-PSKTFSI (run 1, Table 3) and PSKTFSI-b-PMMA (run 3, Table 2) at heating rate of 10 C/min 17
ESI 12 Fig. S12. DSC traces of PSKTFSI-b-PMAA (first and 2 nd heating cycles of two different DSC experiments for same sample) and PMAA (2 nd heating cycle) at heating rate of 10 C/min 18
ESI 13 Fig. S13: DSC traces of PS (M n = 8800 g/mol, D = 1.03) and PMMA (M n = 23000 g/mol, D= 1.2) homopolymers at heating rate of 10 C/min 19
ESI 14 a b e f c c' g g' d d' e e' DMS a,b,e,f S N K c,c,e,e,g,g S H 2 CF 3 CHCl3 d,d Fig. S14: 1 H NMR of PS-b-PSKTFSI in DMS-d 6 /CDCl 3 mixture (run 1, Table 3) at RT. 20
ESI 15 b a RI response 769 819 869 919 969 1019 1069 1119 1169 1219 1269 Elution Time (Sec) Fig. S15: SEC traces of (a) PS homopolymer and (b) PS-b-PSKTFSI (run 1, Table 3).using DMF as an eluent at 60 C 21
ESI 16 Table. S1: Solubility of Polymers synthesized Polymer Water DMF THF NMP EG DMS DMS/Chlorofor m Dioxane PSTFSIK +++ +++ + +++ ++ +++ + - PSTFSIK-b-PS - +++ ++ - - + +++ ++ PSTFSIK-b- PMMA - +++ ++ - - + +++ +++ PSTFSIK-b-PMAA - +++ ++ - - + +++ +++ +++: Good solubility, ++: Medium solubility, +: Partial solubility, -: Not Soluble DMF: Dimethylformamide, THF: Tetrahydrofuran, NMP: N-Methyl-2-pyrrolidone, EG: Ethylene glycol, DMS: Dimethyl sulfoxide [1] J. T. Lai, D. Filla, R. Shea, Macromolecules, 2002, 35, 6754-6756. [2] R. Meziane, J.-P. Bonnet, M. Courty, K. Djellab, M. Armand, Elecrochimica Acta, 2011, 57, 14-19. [3] K. Ellmer, Nat. Photonics 2012, 6, 809 817. [4] Sukanta De, Paul J. King, Philip E. Lyons, Umar Khan, and Jonathan N. Coleman, ACS Nano, 2010, 12, 7064 7072. 22