Supporting Information for Solution Self-Assembly of Block Copolymers Containing a Branched Hydrophilic Block into Inverse Bicontinuous Cubic Mesophases Tae Hyun An, Yunju La, Arah Cho, Moon Gon Jeong, Tae Joo Shin, Chiyoung Park,, * and Kyoung Taek Kim,, * Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST Road, Ulsan 689-798, Korea Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, Korea KIST-UNIST-Ulsan Center for Convergence Materials, Ulsan 689-798, Korea. *Correspondence to: cpark@unist.ac.kr and ktkim@unist.ac.kr S-1
Synthesis of branched macroinitiator with peripheral PEG chains Branched macroinitiators were synthesized in multi-gram quantity by following the literature methods. 1,2 550 3 -Br. 1 H NMR (δ=ppm, 600 MHz, CDCl 3 ) 6.60 (s, 2H), 5.10 (s, 2H), 4.16 (t, 4H, J = 4.8Hz), 4.13 (t, 2H, J = 4.8Hz), 3.86-3.50 (m, -CH 2 CH 2 O-), 3.39 (m, 9H), 1.95 (s, 6H). 13 C NMR (δ=ppm, 150 MHz, CDCl 3 ) 171.2, 152.6, 140.1, 130.8, 107.4, 77.4, 77.1, 76.7, 70.8-70.3, 69.6, 69.6, 68.8, 67.4, 59.0, 55.8, 30.7. M n (GPC) = 2250 g/mol, PDI = 1.03, M n (MALDI-TOF) = 2158 g/mol. 750 3 -Br. 1 H NMR (δ=ppm, 600 MHz, CDCl 3 ) 6.60 (s, 2H), 5.09 (s, 2H), 4.14 (t, 4H, J = 4.8Hz), 4.13 (t, 2H, J = 4.8Hz), 3.86-3.50 (m, -CH 2 CH 2 O-), 3.37 (m, 9H), 1.94 (s, 6H). 13 C NMR (δ=ppm, 150 MHz, CDCl 3 ) 171.3, 152.6, 138.3, 130.7, 107.3, 77.5, 77.2, 76.9, 72.2, 71.8, 70.8-70.2, 69.6, 68.8, 67.3, 58.9, 55.8, 30.7. M n (GPC) = 2762 g/mol, PDI = 1.03, M n (MALDI-TOF) = 2653 g/mol. Scheme S1. Synthesis of branched macroinitiator with peripheral PEG chains (550 3 -Br and 750 3 -Br). S-2
Figure S1. (A) 1 H NMR (600 MHz, CD 2 Cl 2 ) and (B) MALDI-TOF spectra of a 550 3 -Br. S-3
Figure S2. (A) 1 H NMR (600 MHz, CD 2 Cl 2 ) and (B) MALDI-TOF spectra of a 750 3 -Br. S-4
Synthesis of block copolymers (550 3 -PS n and 750 3 -PS n ). Polymerization of styrene was performed with macroinitiators under a standard ATRP condition. 1,2 Representative procedure: CuBr (50 mg, 0.35 mmol) and N,N,N',N'',N''- pentamethyldiethylenetriamine (PMDETA) (108 mg, 0.525 mmol) were mixed with 1 ml of anisole in a 20 ml Schlenk tube with a magnetic bar. The tube was sealed with a rubber septum. This mixture was bubbled with N 2 for 15 min with gentle stirring. To this solution, the solution of styrene (10 ml) and 550 3 -Br (120 mg, 0.035 mmol) was added via a syringe. The green solution was degassed by bubbling N 2 for 20 min. After degassing, the tube was immersed in a preheated oil bath (95 C) and the polymerization was proceed at this temperature. The progress of polymerization was monitored by taking GPC at an interval of 1 h. When the molecular weight of the block copolymer reached to the desired value, the reaction was quenched by exposing the solution to air in an ice/water bath and diluted with CHCl 3 (15 ml). The cooled solution was filtered through a pack of aluminium oxide (basic) with CHCl 3 to remove the Cu catalyst. The filtered solution was concentrated on a rotary evaporator, and the resulting residue was diluted with 20 ml CH 2 Cl 2. This solution was precipitated into methanol (200 ml). White powder was collected by vacuum filtration and dried in vacuo. All block copolymers were characterized by 1 H NMR and GPC to evaluate the molecular weight and the size distribution. The molecular characteristics of the block copolymers are listed in Table 1. Scheme S2. Synthesis of bpeg-pss. S-5
Preparation of 750 3 -(PS n ) 2. Synthesis of methyl-3,5-dipropargyloxybenzoate. A mixture of methyl-3,5- dihydroxybenzoate (10 g, 0.059 mol, 1 eq.) and propargyl bromide (15.2 ml, 0.14 mol, 2.3 eq., 80% in toluene) was stirred for 10 min in acetone (200 ml). K 2 CO 3 (35 g) was then added, and the reaction was stirred for 18 h under reflux. Thereafter, the solid was remove by filtration and acetone was removed by rotary evaporation. Water was added and the mixture was extracted with dichloromethane. The organic phase was dried over MgSO 4 and filtered. The solvent was removed by rotary evaporation and then crystallized in methanol. 1 H NMR (400 MHz, CDCl 3 ) 7.29 (d, J=2.4, 2H), 6.81(t, J=2.4 Hz, 1H), 4.71(d, J=2.4 Hz, 4H), 3.9(s, J=1.6 Hz, 3H), 2.54(t, J=2.4 Hz, 2H). Synthesis of 3,5-dipropargyloxybenzoic acid Methyl-3,5-dipropargyloxybenzoate (1.5 g, 6.1 mmol) was dissolved in methanol (100 ml) and a solution of 2M LiOH in water (15.3 ml) was added. The reaction mixture was stirred at room temperature for 12 h and monitored by TLC. The solvent was removed by rotary evaporation. 2 M HCl was added to the mixture. When ph was dropped to ph 5~6, pale-yellow powder was precipitated. Pale-yellow powder was collected by vacuum filtration and dried in vacuo. 1 H NMR (400 MHz, DMSO-d 6 ) 13.12 (b, 1H), 7.14(d, J=2.3 Hz, 2H), 6.82(t, J=2.3 Hz, 1H), 4.82(d, J=2.3 Hz, 4H), 3.57(t, J=2.3 Hz, 2H). Scheme S3. Synthesis of 3, 5-bisproparyloxybenzoic acid. S-6
Synthesis of 750 3 -bispropargyl ether. 3, 5-Bisproparyloxybenzoic acid (1.8 g, 4.2 mmol, 10 eq.), DCC (0.65 g, 4.2 mmol, 10 eq.), and DMAP (0.051 g, 0.42 mmol, 1 eq.) were dissolved in dry THF (100 ml) at 0. The mixture was dropwise to the CH 2 Cl 2 solution (50 ml) of PEGylated benzyl alcohol (750 3 -OH) (1g, 0.42 mmol, 1 eq.) at 0. The resulting mixture was gradually warmed to room temperature. After 24 h, the crude mixture was cooled, and urea was removed. Then mixture was purified by flash column chromatography (dichloromethane : methanol = 95:5 v/v). 1 H NMR (400 MHz, CDCl 3 ) 7.32(d, J=2.4 Hz, 2H), 6.81 (t, J=2.4 Hz, 2H), 6.66(s, 1H), 5.23(s, 2H), 4.71(d, J=2.4 Hz, 4H), 4.18-4.1(m, 6H), 3.85-3.52(m, -CH 2 CH 2 O-), 3.37(s, 9H), 2.60(t, J=2.4 Hz, 2H). Scheme S4. Synthesis of 750 3 -bispropargyl ether. Synthesis of N 3 -PS. CuBr (40 mg) was charged in Schlenk flask and dried in vacuum for 15 min. N,N,N',N'',N''- pentamethyldiethylenetriamine (PMDETA) (80 mg) dissolved in anisole (1.5 ml) was introduced, and the mixture was stirred under N 2 for 15 min. To this mixture, 1-bromoethyl benzene (100 mg, 0.188 mol) and styrene (7 g, 0.0037 mol) dissolved in anisole were added. After the resulting mixture was bubbled with N 2 for 15 min, the reaction was proceeded at 95. The reaction was quenched by exposing the solution to air in water bath and diluted with chloroform. The cooled solution was filtered through a pack of aluminum oxide (basic) with chloroform to remove the Cu catalyst. The filtered solution was concentrated on rotary evaporation, and then crude products were dissolved in a small amount of dichloromethane and precipitated into methanol. White powder was collected by vacuum filtration and dried in vacuo. Subsequently, the brominated PS (1.5 g, 1.4 mmol, 1 eq.) and sodium azide (0.14 g, 2.1 mmol, 1.5 eq.) were dissolved in DMF (50 ml) and stirred at room temperature. After 10 h, DMF was removed by a S-7
rotary evaporator and precipitated into methanol. The azido terminated PS (N 3 -PS) is dried under vacuum. M n = 5800 g/mol PDI = 1.06 (GPC). M n = 6079.8 g/mol PDI = 1.01 (MALDI-TOF). Synthesis of 750 3 -(PS 57 ) 2. CuBr (40 mg) was dried in vacuum for 15 min. N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) (80 mg) mixed with THF (1.5 ml) was added and the mixture was stirred in N 2 for 15 min. After 750 3 -bispropargyl ether (0.2 g, 0.013 mmol, 1 eq.) and N 3 -PS (2.4 g, 0.4 mmol, 4 eq.) dissolved in THF (3 ml) were added, the mixture was bubbled with N 2 for 15 min. After degassing, the click reaction was proceeded at 40 C. The reaction was quenched by exposing the solution to air in water bath and diluted with chloroform. The cooled solution was filtered through a pack of aluminum oxide (basic) with CHCl 3 to remove the Cu catalyst. The filtered solution was concentrated on a rotary evaporator, and then crude products were dissolved in a small amount of dichloromethane and precipitated into methanol. White powder was collected by vacuum filtration and dried in vacuo. The crude mixture was further purified by preparatory liquid chromatography. M n (GPC) = 14700 g/mol PDI = 1.05 (GPC). Scheme S5. Synthesis of 750 3 -(PS n ) 2. S-8
Figure S3. (A) 1 H NMR (600 MHz, CDCl 3 ) of 750 3 -(PS 57 ) 2. Figure S4. (A) GPC and (B) MALDI-TOF spectra of 750 3 -(PS 57 ) 2. S-9
Preparation of N 3 -PEG 45 -PS 210, NH 2 -PEG 45 -PS 210, and SH-PEG 45 -PS 210. Anionic polymerization of alkyne-terminated PS 210. Distilled styrene was added into 100 ml of dry THF in dry Schlenk round bottom flask. The solution was degassed and charged with N 2 for 20 min. Upon cooling the solution to -76 C, sec-buli solution (cyclohexane, 1 eq.) was instantaneously injected via a syringe. After 1h, the polymerization was quenched by injection of 1-chloro-5-triethylsilyl-4-pentyne (3 eq.) at -76 C. The temperature was raised to room temperature over 2 h. The quenched solution was precipitated into methanol (600 ml), and the white powder was collected. The crude powder was dissolved in THF, and tetrabutylammonium fluoride (TBAF, 10 eq. to the polymer) was added to this solution. The solution was stirred at room temperature for 12 h. The desired product was precipitated in methanol (600 ml) and dried in vacuo. Synthesis of α-functionalized PEG-PSs. Representative procedure: CuBr (30mg, 0.2 mmol) and N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) (53 mg, 0.31 mmol) were mixed with 1 ml of THF in a 20 ml Schlenk tube with a magnetic bar. The tube was sealed with a rubber septum. This mixture was bubbled with N 2 for 15 min with gentle stirring. To this solution, THF solution of alkyne-terminated polystyrene (10 ml, 1.5 eq to PEG macroinitiator) and α-azido PEG was introduced via a syringe. The green solution was degassed by bubbling N 2 for 20 min. After degassing, the tube was immersed in a preheated oil bath (40 C) and the click reaction was proceed at this temperature. The progress of the reaction was monitored by taking GPC. When most of the PEG was react with alkyne-terminated polystyrene, the reaction was quenched by exposing to air and diluted with CHCl 3 (15 ml). The cooled solution was filtered through a pack of basic aluminium oxide with CHCl 3 to remove the Cu catalyst. The filtered solution was concentrated on a rotary evaporator, and the resulting residue was diluted with 20 ml CH 2 Cl 2. This solution was precipitated into methanol (400 ml). White powder was collected by vacuum filtration and dried in vacuo. All block copolymers were characterized by 1 H NMR and GPC to evaluate the molecular weight and the size distribution. NH 2 -PEG 45 -PS 210 was obtained from N 3 -PEG 45 -PS 210 through Staudinger reaction condition. SH- PEG 45 -PS 210 was obtained by deprotection of 2,4-dinitrophenyl moiety in the presence of a large excess ethanethiol and trimethylamine. N 3 -PEG 45 -PS 210. DP n (PS) = 210 ( 1 H NMR). M n = 23,334 g/mol PDI = 1.06 (GPC). NH 2 -PEG 45 -PS 210. DP n (PS) = 210 ( 1 H NMR). M n = 23,024 g/mol PDI = 1.07 (GPC). SH-PEG 45 -PS 210. DP n (PS) = 210 ( 1 H NMR). M n = 23,434 g/mol PDI = 1.06 (GPC). S-10
Scheme S6. Synthesis of α-functionalized PEG-PSs. Synthesis of rhodamine B propargyl ester. The product was obtained according to literature. 3 A mixture of rhodamine B (2.4 g) and EDC (1.535 g) in anhydrous dichloromethane (15 ml) was stirred for 5 min under nitrogen atmosphere, and propargyl alcohol (500 µl) and 4-dimethylaminopyridine (65 mg) were added. The solution was stirred at room temperature for 2 days. The mixture was precipitated in diethyl ether, and subjected to flash column chromatography (MeOH:ethyl acetate = 1:5, v/v). 1 H NMR (600 MHz, CDCl 3 ): 8.31 (d, 1H), 7.82 (m, 2H), 7.3 (m, 1H), 7.2 (d, 2H), 7.05 (d, 2H), 6.8 (d, 2H), 4.62 (s, 2H), 3.6 (q, 8H), 2.4 (s, 1H), 1.3 (t, 12H). S-11
Figure S5. SEM images of the hexasomes of 550 3 -PS 260. S-12
Figure S6. SEM images of (A) vesicles of 750 3 -PS 363, (B) cubosomes of 750 3 -PS 390, and (C) large cubosomes of 750 3 -PS 413, respectively. Figure S7. (A and B) TEM images of the polymer cubosomes of 750 3 -PS 390, showing the thickness of the bilayer membrane consisting of the self-assembled structure. S-13
References 1. Jeong, M. G.; van Hest, J. C. M.; Kim, K. T. Self-Assembly of Dendritic-Linear Block Copolymers with Fixed Molecular Weight and Block Ratio. Chem. Comm. 2012, 48, 3590-3592. 2. La, Y.; Park, C.; Shin, T. J.; Joo, S. H.; Kang, S.; Kim, K. T. Colloidal Inverse Bicontinuous Cubic Membranes of Block Copolymers with Tunable Surface Functional Groups. Nature Chem. 2014, 6, 534 541. 3. Guo, J.; Meng, F.; Jing, X.; Huang, Y. Combination of Anit-Biofoulding and Ino-Interaction by Click Chemistry for Endotoxin Selective Removal from Protein Solution. Adv. Healthcare Mater. 2013, 2, 784 789. S-14